Estimating KWh electicity billing using clamp-on amp meter
Home Guy
service.
The billing meter is in a locked cabinet (for which the local utility
has a key) and out of this cabinet run 4 large cables (each about 1 or
1.25 inches in diameter) that run to their own insulator or terminal
blocks where smaller cables (3/8" diameter) connect to them and run to
separate panels and switch boxes.
All of these large cables are black, and one of them is (I believe) a
neutral or ground (it has a white stripe running down it's length).
A voltage reading from this neutral wire to each of the other 3 terminal
blocks is 120 vac, and voltage readings between the 3 terminal blocks is
about 212 vac.
I have a hand-held amp meter (Fluke 31 true RMS clamp meter) which looks
exactly like this:
http://www.tequipment.net/ProductImages/Fluke/33_ap_w.jpg
I don't know exactly how old this meter is, but I believe it's at least
10 years old and quite possibly 15 years old.
The electrical devices in the building are typical for an office with
some very light manufacturing. About 15 desktop computers, many with
small UPS backup, telephone system, some networking switches and
routers, a few printers, flourescent lighting, a few soldering irons,
microwave, coffee maker, fridge, water cooler / distiller. At this time
or year neither the building's furnace (forced air natural gas) or AC
unit is running (the breaker powering the outdoor AC unit is off).
When I put the meter clamp around each of the 4 large cables, I read
anywhere from 10 to 20 amps on them during normal day-time electrical
usage inside the building. During a test when all computers, monitors,
printers and lights are turned off (but all UPS's are still turned on) I
read a total sum of about 4 or 5 amps across all 4 power cables.
So my questions are:
1) when coming up with a total current measurement, do I include the
current flowing on the neutral line? Should I indeed measure any
current on that line at all - or should the current on the neutral be
equal to the sum of the currents on the other 3 lines?
2) I am not computing the instantaneous power as a product of the
instantaneous voltage and current because I don't know the phase
relationship between the current I'm measuring with the clamp-on meter
and the AC line voltage. But if I take the meter's RMS amp reading (or
the sum of the 3 or 4 readings for each cable) and multiply that by 120,
will I get a power or wattage measurement that is AT WORST the highest
possible energy consumption number I can have (ie - equivalent to if all
the loads were resistive and not inductive) ?
3) There are (on average) 30.4 days in a month, and therefore 730 hours
in a month. If I take the above wattage calculation (120 x
total_current) and multiply it by 730, then divide by 1000, I should get
a quantity energy measurement (KWh) that should match (or approximate)
my bill from the local utility - assuming that the load in use at the
time of the readings are representative of daily or continuous use. If
this method of obtaining a representative monthly KWh measurement is not
correct (or needs more refinement) then please state what, why or how.
RBM
"Home Guy" <Ho...@Guy.com> wrote in message news:4DE03EFD...@Guy.com...
**You're not going to be the least bit accurate trying to calculate that
way. There is no reason that you shouldn't be able to look at the electric
meter. If you really need to self meter the service get an "emon demon" for
3 phase 4 wire 208 volts
Home Guy
> > 3) There are (on average) 30.4 days in a month, and therefore 730
> > hours in a month. If I take the above wattage calculation (120 x
> > total_current) and multiply it by 730, then divide by 1000, I
> > should get a quantity energy measurement (KWh) that should match
> > (or approximate) my bill from the local utility - assuming that
> > the load in use at the time of the readings are representative of
> > daily or continuous use. If this method of obtaining a
> > representative monthly KWh measurement is not correct (or needs
> > more refinement) then please state what, why or how.
>
> **You're not going to be the least bit accurate trying to calculate
> that way.
I want to establish several use-case situations, primarily a
"worst-case" KWh monthly usage by assuming that all the devices that are
normally on during a week-day 9-am to 5-pm work day and turned off at
all other times are instead left on continuously 24/7.
I can also get current readings for other use-case situations (evenings
and week-ends) that should give me a more closer-to-reality current
reading and factor in their time-of use over the course of a month.
This is a small office - not a home. There are fewer variable involved.
> There is no reason that you shouldn't be able to look at the
> electric meter.
The meter is in a locked cabinet. The only time I get to see it is when
the meter-reader guy comes around once a month to read it.
I suspect the meter is in a locked cabinet to prevent tampering / bypass
(the meter is inside the utility / furnace room of the building and is
not accessible from the outside).
And besides, having the ability to lay my eyes on the meter won't tell
me anything about the accuracy of the meter, or the real-time current
consumption.
All I want to know is - should the current readings from a clamp-on
meter (when extrapolated across the 730 hours of a typical month) jive
with the accumulated KWh reading as measured by a typical billing
meter? Do I have to do any "special" math to the wattage I calculate
with the meter to arrive at what the billing meter is measuring?
Mark
yes you are correct you can get a rough reading this way..
you need to measure and sum only the 3 black cables, do not include
the white striped cable in the sum.
Add up the 3 currents and multiply by 120 and this is your VAs and the
actual Watts will be equal to or less then the VAs.
Multiply by hours and you have Watt Hours.
Divide by 1000 and you have kWh which is how you are billed.
Mark
hr(bob) hofmann@att.net
>
> - Show quoted text -
You may be lucky and only have an error of 10 - 20%, but I wouldn't
be surprised if your error was as much as 25%.
RBM
"Mark" <mako...@yahoo.com> wrote in message
news:aceeb9d6-2cfb-40b1...@w36g2000vbi.googlegroups.com...
Mark
This is a commercial service and metering equipment. How is he going to
guestimate demand?
RBM
"Home Guy" <Ho...@Guy.com> wrote in message news:4DE04639...@Guy.com...
**You need to put 3 clamp on meters on the wires and monitor them
continuously over the desired period of time, which still won't be accurate
because they won't give you the peak demand. If you have some reason to
believe that the utility company equipment is faulty, you can request that
the utility company hang a testing meter to verify the accuracy
Home Guy
by full-quoting:
> You may be lucky and only have an error of 10 - 20%, but
> I wouldn't be surprised if your error was as much as 25%.
When you speak of this error, do you mean
a) an error between (what the billing meter is reading in terms of KWh
for some arbitrarily short time span) AND (what my amp-meter derived
watt-measurement would give for the same arbitrarily short time span)
or
b) an error between (the monthly power use of the office derived from
several different measurements with various devices and appliances
turned on or off as per time-of day and day-of-week) AND (the actual or
real pattern of device usage over the course of a real month).
What is the error you speak of?
Ed Pawlowski
"Home Guy" <Ho...@Guy.com> wrote
>
.>
> The meter is in a locked cabinet. The only time I get to see it is when
> the meter-reader guy comes around once a month to read it.
>
> I suspect the meter is in a locked cabinet to prevent tampering / bypass
> (the meter is inside the utility / furnace room of the building and is
> not accessible from the outside).
>
> And besides, having the ability to lay my eyes on the meter won't tell
> me anything about the accuracy of the meter, or the real-time current
> consumption.
>
> All I want to know is - should the current readings from a clamp-on
> meter (when extrapolated across the 730 hours of a typical month) jive
> with the accumulated KWh reading as measured by a typical billing
> meter? Do I have to do any "special" math to the wattage I calculate
> with the meter to arrive at what the billing meter is measuring?
There is no special math, but I'd wonder just how accurate your number is
going to be. Don't for get about seasonal changes too, more lighting in
winter, AC in summer, etc. At work, I take readings on some of our
utilities daily, others, monthly, and can spot a trend when correlated with
material used on a given day, etc. This will often tip you off as to
problem areas and waste when you see aberrations from the norm.
Have you talked to the utility company? Some will do the work for you and
put a recording meter on the line for a week or two to get you want you
want. Your approach, of course, is in the interest of energy conservation.
They are big on selling you less these days.
Reading the meter on a daily basis would be a help to determine trends also.
Perhaps they will allow a window to the meter so you can take readings.
Home Guy
full-quoting:
> This is a commercial service and metering equipment. How is he
> going to guestimate demand?
Demand (or load) doesn't have to be guestimated.
There are a fixed set of lights, appliances and devices in this office,
as well as a relatively fixed schedule of use for them. We have a basic
week-day and week-end pattern, and for the week-days we have diurnal
(day - night) pattern of usage. Since the average month has 730 hours,
comprised of 4.34 weeks, we know that there will be 209 "week-end" hours
and 521 "week-day" hours. The week-day hours can be further decomposed
as 217 "day-time, week-day" hours and 304 "night-time, week-day" hours.
So we have 3 different loading conditions where the energy consumption
during each condition is assumed to be constant: Week-day day-time,
week-day night-time, and week-ends. If a current measurment is
performed once for each of the 3 conditions, and then extrapolated over
their projected duration over the course of a month (217, 304 and 209
hours respectively) then if the three total are summed the result should
approximate what the billing meter should measure if that same exact
device and appliance usage pattern is replicated during a typical month.
The exact hours of each loading condition can be exactly specified to
match a given utility bill if the meter-reading dates are known for the
bill in question (that will tell us how many week-end and week-days
actually occurred during the billing month of interest).
Based on 5 years of previous bills, about 75% of the monthly meter
readings are between 1750 and 2250 kwh. Very few go higher than 3000,
and only 2 have ever gone above 4000.
Metspitzer
>**You need to put 3 clamp on meters on the wires and monitor them
>continuously over the desired period of time, which still won't be accurate
>because they won't give you the peak demand. If you have some reason to
>believe that the utility company equipment is faulty, you can request that
>the utility company hang a testing meter to verify the accuracy
>
They make clamp on amp meters that graph usage over time. I have no
idea how much they cost to buy or rent.
We took amp measurements on a parallel run of 3-500. I was amazed
that supposedly equal lengths of copper varied as much as 25 amps on
the same phase.
Home Guy
> Have you talked to the utility company?
Yes, I have contacted the "front-line" customer service people and
expect to hear more from someone more technical or in more authority (or
at least someone more "male") next week.
Our last bill was for 5,160 kwh, with a billing period from april 5 to
May 4.
The previous month (March 5 - April 4) was 1915 kwh.
Infact, looking at the last 12 bills I see some very suspicious things:
5162.41 April
1915.26 March
1582.17 Feb (meter changed end of Feb)
1998.53 Jan 2011
1915.26 Dec
2081.8 Nov
2664.7 Oct
1498.9 Sept
3414.15 Aug
3913.78 July
1998.53 June
2248.34 May
1915.26 April
1915.26 March
5162.86 Feb
3247.61 Jan 2010
2331.62 Dec 2009
Our meter is always read on the first business day of each month. The
meter was changed at the end of February. The old meter was electronic
(it had a digital LCD readout). The new meter *I believe* is different
in that it can do time-of-use measuring and it can do RF (wireless) data
transmission. Time-of-use billing is not yet being performed in our
area, and at least for our new meter a person is still coming around to
read it.
I note that I see 1915.26 show up suspiciously 4 times during the past
year (what are the odds that we'd use the exact same amount of
electricity for any 2 months, let alone 4?).
It was the large jump from 1915 to 5162 that tweaked me on this and I
had an assistant enter all previous numbers from other bills in a
spreadsheet. The large spike back in Feb 2010 to almost exactly the
same number of 5162 is also suspicious.
I would have expected our electricity use to decline from March to April
given a reduced furnace on-time in April vs March.
I have no idea what remedy or proceedure my utility company follows in
disputes of this nature. I have the vague idea that they circle the
wagons and defend their meters to the last drop of their blood, and that
the laws or service contracts may favor them and not the customer. We
shall see.
Smitty Two
Why do you want to do this?
Ed Pawlowski
"Home Guy" <Ho...@Guy.com> wrote
>
> Our last bill was for 5,160 kwh, with a billing period from april 5 to
> May 4.
> The previous month (March 5 - April 4) was 1915 kwh.
>
> Infact, looking at the last 12 bills I see some very suspicious things:
>
> 5162.41 April
> 1915.26 March
> 1582.17 Feb (meter changed end of Feb)
> 1998.53 Jan 2011
> 1915.26 Dec
> 2081.8 Nov
> 2664.7 Oct
> 1498.9 Sept
> 3414.15 Aug
> 3913.78 July
> 1998.53 June
> 2248.34 May
> 1915.26 April
> 1915.26 March
> 5162.86 Feb
> 3247.61 Jan 2010
> 2331.62 Dec 2009
>
> Our meter is always read on the first business day of each month. The
> meter was changed at the end of February.
> year (what are the odds that we'd use the exact same amount of
> electricity for any 2 months, let alone 4?).
>
> It was the large jump from 1915 to 5162 that tweaked me on this
> I have no idea what remedy or proceedure my utility company follows in
> disputes of this nature. I have the vague idea that they circle the
> wagons and defend their meters to the last drop of their blood, and that
> the laws or service contracts may favor them and not the customer. We
> shall see.
You are correct in being suspicious. My findings from tracking electric,
July and August are the highest, January is second highest. There will be a
curve on the months between. Winter is high because of running heat and more
lighting, then it comes down as you approach spring, then goes up again as
the AC use kicks in. Then in September, it comes down then back up for
winter use.
I can understand with the old meter that you'd possibly get 4 identical
readings if the meter was not read and the bill was estimated. Actual
readings, I'd say "no way" you'd have that situation at that use. We do have
one tenant that uses very little electric and the meter was originally
installed for some machines. It has a multiplier Most bills are the same,
in increments of $18. A few a year are $36. Another has bills in the $400
to $800 range and follows the curves a I outlined.
A couple of possibilities I can think of. The meter is incorrect. (yes, it
really does happen) A tenant is carelessly leaving on a space heater. a
tenant is running both heat and AC out of stupidity, not a maintenance
problem. You have some other pump or device that is running all the time.
Good luck and please keep us posted on what happens.
k...@att.bizzzzzzzzzzzz
>"hr(bob) hof...@att.net" used improper usenet message composition style
>by full-quoting:
>
>> You may be lucky and only have an error of 10 - 20%, but
>> I wouldn't be surprised if your error was as much as 25%.
>
>When you speak of this error, do you mean
>
>a) an error between (what the billing meter is reading in terms of KWh
>for some arbitrarily short time span) AND (what my amp-meter derived
>watt-measurement would give for the same arbitrarily short time span)
An amp meter measures amps, not watts. Even if you assume 120V, you're still
calculating volt-amps, not watts.
>or
>
>b) an error between (the monthly power use of the office derived from
>several different measurements with various devices and appliances
>turned on or off as per time-of day and day-of-week) AND (the actual or
>real pattern of device usage over the course of a real month).
>
>What is the error you speak of?
c) The error between Volt-Ampere-hours and Watt-hours.
The errors you mention above will likely be even bigger, though. Surprisingly,
a watt-hour meter (it's already there) is the real way to measure watt-hours.
;-)
Tony Hwang
Hi,
I am wondering why you are trying to do this? First what is the power
factor in this circuit? If your goal is to increase efficiency to result
in savings, look into that. If you suspect meter is inaccurate you can
request for a replacement. Newer digital meters are more dependable and
accurate. Even my cabin located in the boondogs have digital power,
natural gas meters. You already know typical power consumption pattern.
So what is the purpose?
Smitty Two
"Ed Pawlowski" <e...@snetnospam.net> wrote:
>
> A couple of possibilities I can think of. The meter is incorrect. (yes, it
> really does happen) A tenant is carelessly leaving on a space heater. a
> tenant is running both heat and AC out of stupidity, not a maintenance
> problem. You have some other pump or device that is running all the time.
>
> Good luck and please keep us posted on what happens.
Something seems a tad fishy, but I don't think sampling some current
readings is going to help sort it out. 400 amps of 3-phase is a lot of
juice to run a few computers, lights, and soldering irons. I know the
type of usage that leads to $5000 electric bills, and that ain't it.
OP needs to spend less time fantasizing about how many hours are in a
month and more time inventorying the equipment in the building, talking
to its occupants, and looking for wires running off across the parking
lot to a secret garage lab that glows in the dark.
harry
Yes you can determine the power being consumed but only at the isntant
you have taken a reading. The meters monitor the power constantly.
The three large cables are the phases.
The neutral is smaller because it only carries the "out of balance
current". You can ignore this cable for your purposes.
Multiply the current by the voltage (120 in your case) for each of
the three cables and then add them together & divde by 1000
This actually gives Kva. If there is only heating/incandescent
lighting in the building, this is the same as Kilowatts.
If there are electric motors or uncorrected fluorescent lights, the
Kva needs to be multiplied by the "power factor" to get Kw which you
don't know. In practice it could be anywhere between 1 (unity) or
0.7. For office premises, you could assume 0.9
So there you have it. Current in each phase X 120 X 0.9
Add the three together.
RBM
"Metspitzer" <kilo...@charter.net> wrote in message
news:vir0u6trib0ho62di...@4ax.com...
** That's the sort of meter that the utility company hangs on the service to
test the accuracy of their equipment
Ed Pawlowski
"Smitty Two" <prest...@earthlink.net> wrote in message
news:prestwhich-B7E90...@news.eternal-september.org...
I can visualize someone having a hobby that requires an induction furnace of
some sort. You take all sorts of readings, day and night, and this guy
fires up the furnace on Sunday mornings while you take the family to church
and breakfast..
tra...@optonline.net
My first guess would be that the logical explanation for 1915.26
showing
up 4 times would be that it is some form of an ESTMATED reading
used when they didn't take an actual reading. The odds of that number
showing up 4 times from a true reading would be very low. And if it
has, I'd suggest using it to play the lottery.
Tony Hwang
Hmmm,
Oh, no! Grow op?, LOL
Home Guy
> Something seems a tad fishy, but I don't think sampling some
> current readings is going to help sort it out.
It's a start.
> 400 amps of 3-phase is a lot of juice to run a few computers,
> lights, and soldering irons.
The main disconnect switch before the meter is name-plate rated at 400
amps. It doesn't mean we're going to ever draw that much.
> OP needs to spend less time fantasizing about how many hours are
> in a month and more time inventorying the equipment in the building
I know exactly what equipment is in the building - I work there.
> talking to its occupants
I talk to them every day.
> and looking for wires running off across the parking
> lot to a secret garage lab that glows in the dark.
What-ever.
Another example of a usenet post that starts with a question, and
devolves into "why are you asking?".
I have to waste more time explaining why I want to do something or why I
want certain information about measurement techniques, and instead I get
a bunch of arm-chair blow-hardts that think they know better.
Home Guy
> Yes you can determine the power being consumed but only at the
> instant you have taken a reading.
So I shouldn't assume that, say, a bank or three of florescent lights
won't necessarily draw a constant amount of current?
Or a dozen PC's?
> The three large cables are the phases.
> The neutral is smaller because it only carries the "out of balance
> current".
The neutral is not smaller (physically) than the other 3 cables. It's
the same size.
Most charts I see only go as large as AWG guage size OOOO (almost 1/2
inch diameter). In my case, the cables running from the meter to the
distribution blocks (a run of about 7 or 8 feet) are at least 1 inch
diameter (OD). The conductor diameter is at least 7/8".
> Multiply the current by the voltage (120 in your case) for each of
> the three cables and then add them together & divde by 1000
> This actually gives Kva. If there is only heating/incandescent
> lighting in the building, this is the same as Kilowatts.
> If there are electric motors or uncorrected fluorescent lights,
> the Kva needs to be multiplied by the "power factor" to get Kw
> which you don't know. In practice it could be anywhere between
> 1 (unity) or 0.7. For office premises, you could assume 0.9
So if I don't multiply my VA number by the power factor, then I'm
OVER-ESTIMATING my KWh calculation by 5 or 10%.
Tangent:
Why does my utility apply (add) a 5% "correction factor" to the KWh
measurement that comes from the meter?
George
Poor you and that incredible amount of time you wasted reading three
posts after you clearly described you already know and presented
everything anyone needs to know and everyone didn't catch on that no
questions are allowed and no opinions are wanted..
Home Guy
> My first guess would be that the logical explanation for 1915.26
> showing up 4 times would be that it is some form of an ESTMATED
> reading used when they didn't take an actual reading.
A meter reader always pays a visit to the building either on the first
or second work-day of the month. He reads both the electric and water
meter (both are inside the building and can't be read from the
outside). I know that because we have to escort the reader to the
utility room, and I'm the one that does it about 1/2 the time, and when
someone else does it they tell me they did it.
There is never a month that goes by without someone coming to read the
meter.
Home Guy
> An amp meter measures amps, not watts. Even if you assume 120V,
> you're still calculating volt-amps, not watts.
A volt-amp is a watt, when the load is resistive.
If I perform high-speed sampling of both the voltage and current, and if
I multiply each reading together to get VA for each sample, and if
integrate those VA samples over time, I will get the actual watts or KWh
that I should be billed for. That would correctly take into account
reative / inductive loads (like motors, light ballasts, computer power
supplies, etc).
If I simply calculate watts as equal to VA based on the current
measurement from a clamp-on meter, then I'm over-estimating what the
billing meter is "seeing" because I'd be assuming that all my loads are
resistive. In other words, my calculation of watts = VA can't help but
assume that current and voltage are in phase with each other.
The billing meter knows how to calculate wattage correctly when the
current and voltage is out of phase.
I guess a clamp-on amp meter that also had a couple of voltage probes so
that it could simultaneously measure the voltage could measure true
wattage would be needed.
> The errors you mention above will likely be even bigger, though
> Surprisingly, a watt-hour meter (it's already there) is the real
> way to measure watt-hours. ;-)
As long as the watt-hour meter is working correctly.
Which seems highly suspect given all the info I've been posting here.
Home Guy
> > I have to waste more time explaining why I want to do something or
> > why I want certain information about measurement techniques, and
> > instead I get a bunch of arm-chair blow-hardts that think they
> > know better.
>
> Poor you
No. Poor usenet.
Poor every future poster to any newsgroup that asks a simple technical
question and gets told by the peanut gallery that it's important to know
all the ancilliary circumstances surrounding the question when in
reality in the end those circumstances have no bearing on the question
or it's answer.
dpb
> "k...@att.bizzzzzzzzzzzz" wrote:
>
...
>> The errors you mention above will likely be even bigger, though
>> Surprisingly, a watt-hour meter (it's already there) is the real
>> way to measure watt-hours. ;-)
>
> As long as the watt-hour meter is working correctly.
>
> Which seems highly suspect given all the info I've been posting here.
Far too little real data to infer that (at least yet)... :)
I'd figure it's likely a combination of estimated or leveled billing w/
a catchup period annually and some tenant or group of tenants w/ loads
you're unaware of.
Not that there aren't errors both in manual reading and that the meter
can fault but generally those get caught in routine maintenance checks
and if the meter were, as you say, replaced recently it's not a high
probability.
--
Tony Hwang
Home Guy wrote:
> harry wrote:
>
>> Yes you can determine the power being consumed but only at the
>> instant you have taken a reading.
>
> So I shouldn't assume that, say, a bank or three of florescent lights
> won't necessarily draw a constant amount of current?
>
> Or a dozen PC's?
>
>> The three large cables are the phases.
>> The neutral is smaller because it only carries the "out of balance
>> current".
>
> The neutral is not smaller (physically) than the other 3 cables. It's
> the same size.
>
> Most charts I see only go as large as AWG guage size OOOO (almost 1/2
> inch diameter). In my case, the cables running from the meter to the
> distribution blocks (a run of about 7 or 8 feet) are at least 1 inch
> diameter (OD). The conductor diameter is at least 7/8".
>
>> Multiply the current by the voltage (120 in your case) for each of
>> the three cables and then add them together& divde by 1000
>> This actually gives Kva. If there is only heating/incandescent
>> lighting in the building, this is the same as Kilowatts.
>> If there are electric motors or uncorrected fluorescent lights,
>> the Kva needs to be multiplied by the "power factor" to get Kw
>> which you don't know. In practice it could be anywhere between
>> 1 (unity) or 0.7. For office premises, you could assume 0.9
>
> So if I don't multiply my VA number by the power factor, then I'm
> OVER-ESTIMATING my KWh calculation by 5 or 10%.
>
> Tangent:
>
> Why does my utility apply (add) a 5% "correction factor" to the KWh
> measurement that comes from the meter?
Hmmm,
You know what? You ought to monitor frequency. Usually it is not 60Hz,
the lower it shows power factor is getting worse. Ideally load should be
pure resistive which does not exist in real world. They are mostly
inductive load. There is such a thing called Pf correcting device to
improve efficiency. My SIL owns/operates mechanical moulding business
based on CAD/CAM. His average monthly bill is pretty constant. The
amount of monthly bill is pretty predictable. Other source of energy his
plant use is NG, mainly for heating.
hr(bob) hofmann@att.net
> "hr(bob) hofm...@att.net" used improper usenet message composition style
BOTH
hr(bob) hofmann@att.net
I agree the billing usage numbers look very suspicious.. I would
contact the power company, bypassing the regular customer service, by
calling the chairman's office and working from there. You can usually
get that sort of information from the investor information section of
the stock listing for the company.
mike
You're pushing a very big rock up a hill to nowhere.
Your meter will give you little useful information.
You need to KNOW the phase.
Sticking your finger in your favorite orifice and pulling out a power
factor number is just that...a useless number. You don't
even want to think about the orifices you find here.
Why do you care?
A decision tree is often helpful.
If you think the equipment is faulty, you should enlist the power company.
I've found 'em to be very knowledgeable and helpful. They have the
equipment to determine whether your meter is faulty. A friendly
conversation with customer service should get you a call from
a real engineer. If it turns out to be faulty, make sure you
get calibration numbers off the old system so you can negotiate
a refund.
If you think they're intentionally screwing you, you need to hire
an electrician with the equipment to measure WATTS. That's what you
pay for. Measuring VA is an exercise in futility. Your "finger"
ain't gonna hold up in court anyway.
You might be able to get some advice from the local electrical
inspector.
If you think one of the tenants is charging their electric car
when you're not looking, your amp meter can point you in the right
direction.
I've used current clamps into a computer to log AMPS. Useful
for determining relative consumption from the same load...in
my case it was a water heater.
RMS amps is better than peak or average amps, but still not
a short path to WATTS...well, in the case of a water heater,
it is, but that's a special case of resistive load.
Depending on how the power meter's made, you can get cheap wireless
monitors that you might get the utility to let you clamp
on the meter...but that will have the same systematic
errors that the meter has. But it might help you find
any clandestine loads at odd hours.
Newer digital readout meters have an infrared light that blinks in concert
with the load. Mine is one blink per watt-hour. I programmed
a pda to read out and log consumption in real time. Again, for
my relative use. It has same systematic errors as the meter.
But you still gotta be able to "see" the meter...or put a fiber
optic cable to the outside.
You can buy clamp-on current transformers that also hook to the volts
and measure REAL power accurately. But it's much easier to pick up
the phone and have the power company help you.
The question about the 5% adder is one for customer service.
Did I mention...rock..hill...futility?
Home Guy
> > > You may be lucky and only have an error of 10 - 20%, but
> > > I wouldn't be surprised if your error was as much as 25%.
> >
> > When you speak of this error, do you mean
> BOTH
> > a) an error between (what the billing meter is reading in terms of
> > KWh for some arbitrarily short time span) AND (what my amp-meter
> > derived watt-measurement would give for the same arbitrarily short
> > time span)
That error should be no higher than 10%. The billing meter is measuring
power (watts) that is phase-corrected. My method (of just measuring
current) is not phase corrected. So my calculation of watts will always
be higher by 5 or 10%. If all the loads in the building were purely
resistive, then my method should exactly match the billing meter.
> > b) an error between (the monthly power use of the office derived
> > from several different measurements with various devices and
> > appliances turned on or off as per time-of day and day-of-week)
> > AND (the actual or real pattern of device usage over the course
> > of a real month).
The variability or error in actual device or appliance usage is (I would
think) quite low, given that this is an office environment where the
duty cycle (ie the on/off power cycle pattern) of all of the 15 or so
computers is very regular and known, as are the lights.
The lights and computers probably account for 50 to 75% of the
electricity usage, the rest being fixed electronic infrastructure
(networking routers / switches / DSL modem, multi-function printer-fax,
multi-line phone system) a few low-power exit lights, a couple out-door
75 watt out-door mercury vapor lights (on a mechanical timer), an 18 CF
refrigerator, small microwave, a small capacity water distiller /
chiller (instead of bottled water), a toaster, a couple of small
bathroom ventillation fans wired to the bathroom light switches, the
furnace fan (granted it's a large motor, 220 VAC and probably 1 hp) but
it's not running all the time, a couple of radios.
Smitty Two
No bearing on the question or its answer? If there ever was an answer
(how much current is running through a wire at a given moment in time)
that has no bearing on the question (why does my electric bill
occasionally come in at 3x normal), you certainly postulated it. Some of
us are trying to steer you towards relevancy, and you keep on chasing
nonsensical "tests" that could hardly be less informative.
tra...@optonline.net
Then I'd have a conversation with the electric company and
ask them to explain how 4 months in a year can have
the exact same usage, down to the hundreth of a kwh. And how
there are two other month pairs where the usage is exactly
the same down to less than 1 kwh. It's possible but the
probablities are clearly very low. Even if you had a truly fixed
load that never varied, you'd expect more variation than
that due to some months having more days.
possible and we could calcu
Home Guy
full-quoting:
> You're pushing a very big rock up a hill to nowhere.
I should not see a huge spike in monthly usage during a month when our
hvac usage is practically zero. Investigating the reasons for this
spike is not path to nowhere.
> Your meter will give you little useful information.
An unnecessarily dramatic statement.
To say that a clamp-on amp meter can't give useful information is
hyperbole.
> You need to KNOW the phase.
To the extent that my aggregate power factor is less than .95 or .9,
yes, then I need to know the phase.
Are you suggesting that my effective power factor is likely to be less
than .9?
What is the power factor of 10 to 20 year-old florescent lamp ballasts?
Or a 1 hp, 220 VAC fan motor? Or a 10 year old refridgerator? Or a
typical desktop PC power supply?
Those are the largest (and probably only) non-resistive loads in
question here.
> Why do you care?
Because I pay the bills. What a stupid ass question that was.
> If you think the equipment is faulty, you should enlist the power
> company.
I've already stated that I've contacted them, and that I expect to
encounter difficulty in having them ever admit that their metering
equipment could be faulty or even undertake a process to evaluate the
meter, but I will pursue every course of action and give them every
chance to determine that.
> I've found 'em to be very knowledgeable and helpful.
In the pages and pages of materials and contracts that exist for this
utility, describing all manner of service obligation and liability,
billing, etc, I find nothing in print that defines a process whereby a
billing meter is tested or what is done if a meter is found to be
defective.
There is absolutely nothing I can find in writing even contemplating the
possibility of a meter that does not measure correctly.
I believe that issue is a political "hot potatoe" for all municipal
electricity suppliers, something they'd rather not have to deal with and
hence they largely remain silent about it.
> If you think they're intentionally screwing you,
I believe that they never "intentionally" screw anyone, but that instead
they put up a front that their meters are always correct, all the time,
and reinforce that by not mentioning the possibility of erroneous meter
operation anywhere in any printed material they make available, let
alone define in writing a process or methods to test a meter that the
client believes is suspect.
> Measuring VA is an exercise in futility.
The worst I can do by measuring VA is to OVER-ESTIMATE my watts used by
5 or 10% - unless you think it's likely that my aggregate power factor
is less than 90%.
> Your "finger" ain't gonna hold up in court anyway.
Making my own measurements would be a first-step. I never said I'd use
those measurement in court (that is your hyperbole again).
If indeed it got that far, then I would investigate my options have
having an acredited third-party measurement performed, and that would
only happen if my local utility did not perform their own tests that I
was satisfied was unbiased and accurate.
mm
>
>
>All I want to know is - should the current readings from a clamp-on
>meter (when extrapolated across the 730 hours of a typical month) jive
Jibe.
I know I sound pedantic, but I want you to look your best when
complaining to the electric company, should it come to that point.
>with the accumulated KWh reading as measured by a typical billing
>meter? Do I have to do any "special" math to the wattage I calculate
>with the meter to arrive at what the billing meter is measuring?
Metspitzer
You should ask for a refund
bob haller
with friends watching building.
I had a customewr at a local shopping mall they had electrical
troubles and found a connection from their meter powering public
spaces in the mall, seemingly left over from the malls construction in
the 60s. Tenants on that meter had been paying a big chunk of the
malls electric bill..
This was identified one night when the customer had a fire. The fire
department pulled the meter blacking out a big piece of the mall.
The mall claimed no knowledge:( I believe there was a lawsuit,,,,,,
Evan
@Home Guy:
It is a poor craftsman that blames the tools...
Ask a question based in this reality (rather than your fantasy which
is filled with gaps in your practical knowledge that someone could
drive a box truck through) and you can get an answer...
Ask a fishy question that doesn't sound right to people who *do*
know, and they will want to know more about the situation before
they chime in with their opinion...
You very poorly defined your "issue" to begin with and then you
focused on techno-babble and ill-advised methods to attempt
to monitor your power usage... When there are devices that
are purpose made and could be bought and installed in any
panel whose power consumption you wish to monitor...
~~ Evan
Evan
@Home Guy:
Ah, the true picture emerges -- an accounts payable rep who thinks
that because they pay the bills they understand how everything
works...
You clearly lack the technical expertise to do anything about this
on YOUR side of the meter...
You seem to not understand the regulations which protect consumers
and control how power is sold in your state -- therefore you are
unaware
of your potential remedies in this "situation" if one really exists...
Instead of spending your time researching something actually useful
which might shed some light on what is actually going on (if anything
really is at all) you have chosen to ask stupid questions which are
clearly not on the proper wavelength to make any sense to someone
who actually understands electrical issues AND you are chasing after
something *YOU* can do which would support *YOUR* claim that
your electrical meter is not functioning correctly when there may
in fact be a procedure to follow which has already been defined by
the public utilities commission (or equivalent in your state) which
would almost always involve bringing in an uninterested third
party with the proper credentials and equipment to assess what
if anything is happening in this whole convoluted story...
It seems whenever you get some sound advise that would make
sense in the real world, you attack the contributor because the
person didn't respond with the specific answer you were looking
for in your especially preferred format... So you critique based
on newsgroup etiquette and posting format rather than the
supplied content -- keep doing that and you will be properly
labeled as a troll and written off as such...
~~ Evan
Evan
@bob haller:
That doesn't sound like it was a professionally managed "mall"...
Sounds more like it was being run by people like Home Guy...
All the malls I have seen inside of have entirely separate
switchgear to power tenant versus house circuits...
~~ Evan
Evan
@Home Guy:
You are the one being the UseNet douche here guy...
Commercial electricity is metered based on peak demand
I don't care where you are in the US, it is the way federal
laws on the buying and selling of energy are written...
That first given established, you totally blew off the source
of the *most* qualified electrical advice on this newsgroup
supplied by RBM because you didn't like the 'format' of
his posting method and so called 'etiquette' violations
when your postings actual content is way out in orbit
of some other planet...
Now let us address the specific issues you seem to
be experiencing:
-- Your electrical meter is locked within a cabinet
enclosure where *you* the consumer are unable
to observe the cumulative readings on it at various
points during the billing period to determine any
abnormal usage issues...
That is *highly* abnormal for a meter to be locked
inside a cabinet like that where the indicator of
the amount of electricity you are going to be billed
for is concealed from you... I would place a call
to the local public utilities official and explain your
situation and that your meter is hidden away from
you where you can not read it but once a month
when the power company unlocks its cabinet,
that install does not sound kosher -- at the very
least an observation hole can be made in the
cabinet so you can see your meter...
-- Is there only *one* tenant in this "building"
as it sounds like there is only one meter...
That is an abnormal way to pay for electricity
in a commercial building if there are multiple
tenants irregardless of whether the lease
terms are gross or net (NN) (NNN)...
With one meter all you would be able to do
legally without some sort of sub-metering
involved (the emon demon that RBM mentioned)
is divide the total cost by the square footage
of the building and apportion it to the tenants
based on the tenant's square footage...
-- You are so caught up in the minutiae of how
you can home brew a way to calculate your
power use by simply calculating all the wattage
of all the devices and appliances used in your
occupancy that you seem blissfully unaware
that many things require a "starting current"
like your furnace motor and the ballasts for
those exterior light fixtures on the mechanical
timer -- with a commercial electrical service you
get billed for the highest simultaneous demand
for current as well as the simple kWh of usage...
It sounds to me like you have a lot to learn before you
even attempt to dispute anything with anyone...
It is also waaaay to late to dispute charges for
electricity billed like over a year ago -- there is usually
a time limitation which covers when you can challenge
a utility bill, I have never heard of one that let you go
more than 60-90 days after the billing date to initiate
a complaint...
Good luck man -- hope you can return safely to
earth since you are clearly in orbit somewhere with
all of this...
~~ Evan
k...@att.bizzzzzzzzzzzz
>"k...@att.bizzzzzzzzzzzz" wrote:
>
>> An amp meter measures amps, not watts. Even if you assume 120V,
>> you're still calculating volt-amps, not watts.
>
>A volt-amp is a watt, when the load is resistive.
That's a *BIG* assumption.
>If I perform high-speed sampling of both the voltage and current, and if
>I multiply each reading together to get VA for each sample, and if
>integrate those VA samples over time, I will get the actual watts or KWh
>that I should be billed for. That would correctly take into account
>reative / inductive loads (like motors, light ballasts, computer power
>supplies, etc).
Yes, or you could just use the kWH meter the power company gave you.
>If I simply calculate watts as equal to VA based on the current
>measurement from a clamp-on meter, then I'm over-estimating what the
>billing meter is "seeing" because I'd be assuming that all my loads are
>resistive. In other words, my calculation of watts = VA can't help but
>assume that current and voltage are in phase with each other.
That's what everyone has been telling you, yes. Did you actually read any of
this thread?
>The billing meter knows how to calculate wattage correctly when the
>current and voltage is out of phase.
...and it ignores harmonics. It's a smart little thing.
>I guess a clamp-on amp meter that also had a couple of voltage probes so
>that it could simultaneously measure the voltage could measure true
>wattage would be needed.
Nope. You're still reading VA, not watts.
>> The errors you mention above will likely be even bigger, though
>> Surprisingly, a watt-hour meter (it's already there) is the real
>> way to measure watt-hours. ;-)
>
>As long as the watt-hour meter is working correctly.
Have them calibrate it (they're replace it with one that is calibrated).
>Which seems highly suspect given all the info I've been posting here.
Maybe *you* suspect it. They're really pretty good.
k...@att.bizzzzzzzzzzzz
They can often get a limited refund from the power company, who will then add
it back into the mall's bill. If not, a suit is certainly in order.
Jim Yanik
>
> "Mark" <mako...@yahoo.com> wrote in message
> news:aceeb9d6-2cfb-40b1...@w36g2000vbi.googlegroups.com...
> On May 27, 8:47 pm, Home Guy <H...@Guy.com> wrote:
>> RBM used improper usenet message composition style by full-quoting:
>>
>> > > 3) There are (on average) 30.4 days in a month, and therefore 730
>> > > hours in a month. If I take the above wattage calculation (120 x
>> > > total_current) and multiply it by 730, then divide by 1000, I
>> > > should get a quantity energy measurement (KWh) that should match
>> > > (or approximate) my bill from the local utility - assuming that
>> > > the load in use at the time of the readings are representative of
>> > > daily or continuous use. If this method of obtaining a
>> > > representative monthly KWh measurement is not correct (or needs
>> > > more refinement) then please state what, why or how.
>>
>> > **You're not going to be the least bit accurate trying to calculate
>> > that way.
>>
>> I want to establish several use-case situations, primarily a
>> "worst-case" KWh monthly usage by assuming that all the devices that are
>> normally on during a week-day 9-am to 5-pm work day and turned off at
>> all other times are instead left on continuously 24/7.
>>
>> I can also get current readings for other use-case situations (evenings
>> and week-ends) that should give me a more closer-to-reality current
>> reading and factor in their time-of use over the course of a month.
>>
>> This is a small office - not a home. There are fewer variable involved.
>>
>> > There is no reason that you shouldn't be able to look at the
>> > electric meter.
>>
>> The meter is in a locked cabinet. The only time I get to see it is when
>> the meter-reader guy comes around once a month to read it.
>>
>> I suspect the meter is in a locked cabinet to prevent tampering / bypass
>> (the meter is inside the utility / furnace room of the building and is
>> not accessible from the outside).
>>
>> And besides, having the ability to lay my eyes on the meter won't tell
>> me anything about the accuracy of the meter, or the real-time current
>> consumption.
>>
>> All I want to know is - should the current readings from a clamp-on
>> meter (when extrapolated across the 730 hours of a typical month) jive
>> with the accumulated KWh reading as measured by a typical billing
>> meter? Do I have to do any "special" math to the wattage I calculate
>> with the meter to arrive at what the billing meter is measuring?
>
> yes you are correct you can get a rough reading this way..
> you need to measure and sum only the 3 black cables, do not include
> the white striped cable in the sum.
>
> Add up the 3 currents and multiply by 120 and this is your VAs and the
> actual Watts will be equal to or less then the VAs.
>
> Multiply by hours and you have Watt Hours.
>
> Divide by 1000 and you have kWh which is how you are billed.
>
> Mark
>
>
> This is a commercial service and metering equipment. How is he going to
> guestimate demand?
>
>
>
since the white return wire returns the current from all 3 phases,wouldn't
that give you the sum of all the currents?
Perhaps a more accurate measurement of total power than the other way.
--
Jim Yanik
jyanik
at
localnet
dot com
tra...@optonline.net
> "RBM" <r...@live.com> wrote innews:4de064ae$0$7953$607e...@cv.net:
>
>
>
>
>
>
>
> > "Mark" <makol...@yahoo.com> wrote in message
>
> - Show quoted text -
It would seem to me that if the one white return wire returned
the current from all 3 phases it would have to be one hell
of a conductor.
RBM
"Jim Yanik" <jya...@abuse.gov> wrote in message
news:Xns9EF3A6C3EF48F...@216.168.3.44...
No, the neutral only carries the imbalanced load, which is why it is allowed
to be smaller than the ungrounded legs
Mark
> "RBM" <r...@live.com> wrote innews:4de064ae$0$7953$607e...@cv.net:
>
>
>
>
>
no the white wire returns only the UNBALANCED current
I agree the OP should gain access to the real meter so he can read the
meter say once a day and find out what is going on.
Mark
RBM
"Home Guy" <Ho...@Guy.com> wrote in message news:4DE06EC9...@Guy.com...
> RBM used improper if not deplorable usenet message composition style by
> full-quoting:
>
>> This is a commercial service and metering equipment. How is he
>> going to guestimate demand?
>
>
> Do you have a demand meter?
Do you know what a demand meter is?
Typically commercial meters register peak demand and that peak demand figure
is used as a multiplier
k...@att.bizzzzzzzzzzzz
Only the *difference* of the three phases is returned in the neutral. With a
balanced load there will be zero current in the neutral.
Home Guy
> Do you have a demand meter?
I have no idea. I would think that most utility companies try to
communicate as infrequently and as minimally as possible with their
customers.
We bought this building 6 years ago. What-ever meter it had is
what-ever meter it had. When we wanted the lights to come on, we placed
a call to the local utility and at some point soon after the lights came
on.
They don't seem to be in the habbit of sending a welcome basket along
with a nice, comprehensive information package telling us what choices
of meters and electrical service we have, nor a copy of the
NIST-traceable certification for the meter.
> Do you know what a demand meter is?
Never heard of it.
> Typically commercial meters register peak demand and that peak
> demand figure is used as a multiplier
What would be the criteria for determining when a "demand meter" is
installed in a given premises, vs a non "demand-meter" ?
Does a "demand meter" give a more accurate measure of energy
consumption?
dpb
...
> Does a "demand meter" give a more accurate measure of energy
> consumption?
It's the tariff schedule. Call the business office or look at the bill;
it'll tell you what your rate(s) are.
It's not unusual as others have said for commercial to be on such a
tariff but it's more generally so for manufacturing than simply office
but it'll all depend on where you are.
As somebody else has noted, there will be very specific rules in the
state in which you're located regarding what the utility is required to
do regarding a question regarding billing. Look at that information
that is bound to be available from your state rate commission or
whatever the equivalent is called where you are.
Messing around as you're doing isn't going to get you anywhere at all
useful.
Have you evn verified that the meter is actually physically read on a
monthly basis rather than estimated and the balloon "reading" isn't
simply the annual catchup when they finally do read it? As mentioned
before that would certainly be one possible explanation.
--
harry
> "RBM" <r...@live.com> wrote innews:4de064ae$0$7953$607e...@cv.net:
>
>
>
>
>
>
>
>
> - Show quoted text -
Don't you know anything? If all three phases had the same
current,there would be zero current in the neutral.
harry
fewminutes
The purpose of a demand meter is to discourage the electric consumer
from high peaks in demand. Usually there is an additional charge that
depends on this peak.
The reason for this is the cable and generating capacity has to be
sized to the peak.
Evan
>
> What would be the criteria for determining when a "demand meter" is
> installed in a given premises, vs a non "demand-meter" ?
>
> Does a "demand meter" give a more accurate measure of energy
> consumption?
@Home Guy:
A "demand meter" comes into play as a factor when:
-- The size of the electrical service is exceeds a certain
predetermined size...
-- The property is zoned commercial/industrial usually
will have a demand meter unless you are a small tenant
with a separate meter and your electrical service capacity
is smaller than the predetermined size mentioned above...
A "demand meter" is no more or less accurate than the
meter you have installed on your house -- it is simply
keeping track of an additional aspect to your power use,
rather than only being an odometer counting how many
kWh of energy you are using in a month, it is also keeping
track of what your greatest simultaneous draw of energy
(a.k.a. your "peak demand") was during the billing period
which like others have said acts as a multiplier or
determines which billing rate you will be charged for your
electric bill for that month...
With a "demand meter" service, a business which uses
a consistent 20KW of electrical energy during a billing
period would pay a different rate than a customer who
uses 100KW of electrical energy in short bursts even
if the overall consumption of kWh during said billing
period was identical...
~~ Evan
The Ghost in The Machine
EVANGELIST, NOW WHY DO YOU WANT TO COMPLICATE THE OPs LIFE WITH THAT
KIND OF INFO?
A BETTER WAY FOR A HOME OWNER / CONSUMER TO ESTIMATE HIS COST IS TO
MONITOR HIS USAGE VS HIS COST ON A MONTH TO MONTH BASIS.....IF HE MISSE
$ BY A FEW DIGIT$ ITS NOT THE END OF THE WORLD :) AND THE LESSON IN
OVERUSE IS A GOOD ONE TO MAKE AMENDS AND APPLY SAVING
MEASURES...WHETHER IT MAY BE FIRING AN UNSCRUPULOUS ENERGY WASTING
EMPLOYEE OR CHANGING TO MORE ENERGY EFFICIENT EQUIPMENT OR CURBING USE
TO MEET ONES FISCAL BUDGET.
WHY BOTHER WITH CALCULATIONS IF YOU ARE GONNA SCREW IT UP ANYWAY ;-)
PAT ECUM
TGITM
George
> George wrote:
>
>>> I have to waste more time explaining why I want to do something or
>>> why I want certain information about measurement techniques, and
>>> instead I get a bunch of arm-chair blow-hardts that think they
>>> know better.
>>
>
> No. Poor usenet.
Not at all. If you walked into a room and presented your "novel" ideas
to folks who have a clue and understand what could be done and why your
ideas make very little practical sense they would respond in the same
fashion asking "why" in order to discover if there was something you
didn't convey or to offer a better idea.
>
> Poor every future poster to any newsgroup that asks a simple technical
> question and gets told by the peanut gallery that it's important to know
> all the ancilliary circumstances surrounding the question when in
> reality in the end those circumstances have no bearing on the question
> or it's answer.
See above.
mike
> mike used improper usenet message composition style by unnecessarily
> full-quoting:
>
>> You're pushing a very big rock up a hill to nowhere.
>
> I should not see a huge spike in monthly usage during a month when our
> hvac usage is practically zero. Investigating the reasons for this
> spike is not path to nowhere.
Investigating is good. The method you're using is the rock
to nowhere.
Get a tool that can do the job...and he works for the power company.
>
>> Your meter will give you little useful information.
>
> An unnecessarily dramatic statement.
>
> To say that a clamp-on amp meter can't give useful information is
> hyperbole.
>
>> You need to KNOW the phase.
>
> To the extent that my aggregate power factor is less than .95 or .9,
> yes, then I need to know the phase.
>
> Are you suggesting that my effective power factor is likely to be less
> than .9?
Yes, I am.
If you have a bunch of CFL lights and nothing else running, your
aggregate PF can be 0.6.
During the day, when the lights are off and motors are running, it
might be 0.6 in the other direction. The power meter only cares about
what's happening NOW.
There's a lot of legislation in place or on the way to make NEW
stuff do internal power factor correction. But it's gonna take a while
to make a difference.
Power factor is a mythical number that assumes that voltage and current
are both perfect sine waves that are out of phase.
Take a look at the load from your computer. You might find that
it's a bunch of narrow spikes that bear no resemblance to sine waves.
A "kill a watt" meter will give you a power factor number, but the
crest factor may be WAY bigger than 1.
The only number that makes ANY difference is the one after the $ on your
bill.
Quit messing around and get the power company out to look at it.
Show them the evidence you're bitching about here. Only they can
do anything about it.
>
> What is the power factor of 10 to 20 year-old florescent lamp ballasts?
> Or a 1 hp, 220 VAC fan motor? Or a 10 year old refridgerator? Or a
> typical desktop PC power supply?
>
> Those are the largest (and probably only) non-resistive loads in
> question here.
>
>> Why do you care?
>
> Because I pay the bills. What a stupid ass question that was.
>
>> If you think the equipment is faulty, you should enlist the power
>> company.
>
> I've already stated that I've contacted them, and that I expect to
> encounter difficulty in having them ever admit that their metering
> equipment could be faulty or even undertake a process to evaluate the
> meter, but I will pursue every course of action and give them every
> chance to determine that.
>
>> I've found 'em to be very knowledgeable and helpful.
>
> In the pages and pages of materials and contracts that exist for this
> utility, describing all manner of service obligation and liability,
> billing, etc, I find nothing in print that defines a process whereby a
> billing meter is tested or what is done if a meter is found to be
> defective.
>
> There is absolutely nothing I can find in writing even contemplating the
> possibility of a meter that does not measure correctly.
What's on the paper is inconsequential until you get into a court of law.
Fret over that when it happens.
CALL THE POWER COMPANY...you don't appear to have the skills or
equipment to make a challenge.
>
> I believe that issue is a political "hot potatoe" for all municipal
> electricity suppliers, something they'd rather not have to deal with and
> hence they largely remain silent about it.
>
>> If you think they're intentionally screwing you,
>
> I believe that they never "intentionally" screw anyone, but that instead
> they put up a front that their meters are always correct, all the time,
> and reinforce that by not mentioning the possibility of erroneous meter
> operation anywhere in any printed material they make available, let
> alone define in writing a process or methods to test a meter that the
> client believes is suspect.
>
>> Measuring VA is an exercise in futility.
>
> The worst I can do by measuring VA is to OVER-ESTIMATE my watts used by
> 5 or 10% - unless you think it's likely that my aggregate power factor
> is less than 90%.
>
>> Your "finger" ain't gonna hold up in court anyway.
>
> Making my own measurements would be a first-step. I never said I'd use
> those measurement in court (that is your hyperbole again).
It's my assertion that GETTING THE POWER COMPANY TO INVESTIGATE
is the first step.
The second step is to call whatever agency regulates the power company.
Attempting to measure it yourself is way down the list. You ain't got the
equipment to prove 'em wrong.
George
tra...@optonline.net
in a box that is locked? I've never seen this before.
Do you know if similar meters are all locked? Why
not ask the electric company to leave the box unlocked?
That way at least you could see what the actual meter
is doing.
Home Guy
> > Does a "demand meter" give a more accurate measure of energy
> > consumption?
(I note that no explicit answer is given for that question)
> It only shows the maximum. Usually they only show peaks that
> last a few minutes
> The purpose of a demand meter is to discourage the electric
> consumer from high peaks in demand. Usually there is an
> additional charge that depends on this peak.
So are you saying that customers with "demand meters" are billed on the
basis of their peak demand - a reading based on only a few minutes worth
of energy usage as seen over an entire billing period?
How is that a fair or equitable way to bill a customer?
Are commercial customers that typically use between 2000 and 3000 kwh of
electricity per month normally considered as candidates for a demand
meter, or are they used for much higher usage customers?
Home Guy
> Here's a question no one has asked. Why is the meter
> in a box that is locked? I've never seen this before.
That question was posed earlier in this thread, and I speculated as to
the reason for a locked cabinet in a post I made on Friday night (8:47
pm est):
============
The meter is in a locked cabinet. The only time I get to see it is when
the meter-reader guy comes around once a month to read it.
I suspect the meter is in a locked cabinet to prevent tampering / bypass
(the meter is inside the utility / furnace room of the building and is
not accessible from the outside).
==========
Based on the following (and others which I'm not including) I don't
think it's uncommon for billing meters to be located in locked cabinets,
or "cupboards" (a term used in the UK):
====================
http://www.horizonpower.com.au/downloads/comm_partners/metering/metering_requirement.pdf
Multiple occupancy premises must have their meters readily accessible at
all times and comply with section 6 of the WAER, unless remote reading
facilities are installed. Where meters are located within a locked
meter-box/ cabinet or enclosed area, an approved Horizon Power master
lock must be fitted, allowing Horizon Power access to the meters at all
times. The disengaging of electronic security systems to obtain access
to the meters is not acceptable. Such cases will require an automated
reading system (AMR) to be installed.
====================
See also:
http://forums.moneysavingexpert.com/showthread.php?t=2207277
And this:
==================
http://thestar.com.my/news/story.asp?file=/2011/5/21/sarawak/8727246&sec=sarawak
See explained that Lee’s electricity meter was locked inside a
centralised cabinet outside his premises and three of the eight meters
inside the cabinet were found with signs of attempted tampering.
===================
And this:
=================
http://forums.whirlpool.net.au/archive/1414092
I live in a small townhouse block with 3 dwellings. We are in an Energy
Australia distribution area.
Our electricity meters are all together in a locked metal cabinet near
the street. These connect with underground wiring to a breaker box in
each house's garage.
==================
And this:
===============
http://www.theanswerbank.co.uk/Law/Question512492.html
When the houses were built, it was decided that the electricity meters
of each property would be placed in a 5ft x 3ft metal wall cabinet on
the outside gable end wall of an end property of each terrace of
houses. Recently, a new tenant has moved into the end property of my
terrace of houses and he has proved to be quite an objectionable and
difficult character. He is very unsympathetic towards my need to check
my meter and to make matters worse, the council has locked the cabinet
and provided him with a key just like they've done with other terrace
blocks on the estate.
=================
dpb
> harry wrote:
>
>>> Does a "demand meter" give a more accurate measure of energy
>>> consumption?
>
> (I note that no explicit answer is given for that question)
No. It's immaterial to the usage; only determines what the appropriate
rate will be. Again, that only will matter if you're actually on a
demand-based billing (which, personally, I would doubt for a small
office-type complex, but wouldn't be impossible).
...
> So are you saying that customers with "demand meters" are billed on the
> basis of their peak demand - a reading based on only a few minutes worth
> of energy usage as seen over an entire billing period?
Yes
> How is that a fair or equitable way to bill a customer?
What's "fair" got to do with it? :)
It's owing to the fact that as another already posted, facilities have
to be provided by the utility to handle the peak load; that costs more
so they bill more. It's also an incentive to the customer to look at
load-leveling techniques aggressively to cut their costs.
> Are commercial customers that typically use between 2000 and 3000 kwh of
> electricity per month normally considered as candidates for a demand
> meter, or are they used for much higher usage customers?
Generally, much higher.
All you'll have to do is look at your bill and you'll know what the
tariff schedule is.
Again, you're looking in the wrong place here, first.
In all likelihood, the "problem" is _NOT_ in the metering but in either
having an unknown or parasitic load, the "reading" not being actual
reading but estimated until the "catch up" real reading at the beginning
of the year or other explainable issue. The likelihood of your meter
being in error is quite low for the explanation of the usage data you
previously posted.
--
Ed Pawlowski
"Home Guy" <Ho...@Guy.com> wrote
> harry wrote:
>
>> > Does a "demand meter" give a more accurate measure of energy
>> > consumption?
>
> (I note that no explicit answer is given for that question)
The accuracy is the same range as any other meter.
>
>> It only shows the maximum. Usually they only show peaks that
>> last a few minutes
>> The purpose of a demand meter is to discourage the electric
>> consumer from high peaks in demand. Usually there is an
>> additional charge that depends on this peak.
>
> So are you saying that customers with "demand meters" are billed on the
> basis of their peak demand - a reading based on only a few minutes worth
> of energy usage as seen over an entire billing period?
There is some confusion here. Power factor then is the ratio of active
power to total power.
Power factor comes into play, mostly when you have a lot of large motors.
Yes, you set the reading during startup with the inefficient motors. You
can correct this by using a bank of capacitors properly sized. Or with a
capacitor at each of the large users, such as a 150 HP air compressor.
I don't claim to understand it all, but I do know it exists.
http://en.wikipedia.org/wiki/Power_factor
http://www.myronzucker.com/calmanualpg1.html
>
> How is that a fair or equitable way to bill a customer?
Questionable, but done all the time.
dpb
...
>> How is that a fair or equitable way to bill a customer?
> Questionable, but done all the time.
What's there to question about it?
As noted, the utility must supply the facilities and generation capacity
to satisfy peak demand, not average. That costs and the use of
demand-based tariffs provides a strong incentive to the end user to be
aggressive in implementing load-leveling techniques to the end benefit
of both utility and themselves.
--
gree...@neo.rr.com
>So are you saying that customers with "demand meters" are billed on the
>basis of their peak demand - a reading based on only a few minutes worth
>of energy usage as seen over an entire billing period?
>
No. As others have said, the peak determines the rate used. For
example, if your peak is below 5 KW, then you might be billed at 12
cents per KWH. If your peak goes above 5 KW, you might be billed at
15 cents per KWH. Those are just made up numbers. Your rates at
various peaks will be different. In summary, your peak is based on
just a few seconds, but you bill is still based on actual usage.
Tony Hwang
>
> Instead of spending your time researching something actually useful
> which might shed some light on what is actually going on (if anything
> really is at all) you have chosen to ask stupid questions which are
> clearly not on the proper wavelength to make any sense to someone
> who actually understands electrical issues AND you are chasing after
> something *YOU* can do which would support *YOUR* claim that
> your electrical meter is not functioning correctly when there may
> in fact be a procedure to follow which has already been defined by
> the public utilities commission (or equivalent in your state) which
> would almost always involve bringing in an uninterested third
> party with the proper credentials and equipment to assess what
> if anything is happening in this whole convoluted story...
>
> It seems whenever you get some sound advise that would make
> sense in the real world, you attack the contributor because the
> person didn't respond with the specific answer you were looking
> for in your especially preferred format... So you critique based
> on newsgroup etiquette and posting format rather than the
> supplied content -- keep doing that and you will be properly
> labeled as a troll and written off as such...
>
> ~~ Evan
Hmmm,
BOTTOM LINE>>>>every single dime.
Sounds like OP is Scrooge, will be only happy when he gets free power.
His building may be 100 years old containing industrial revolution era
stuffs.
Proper course of action would cost $$$ which is not in his book. My take
on this thread.
tra...@optonline.net
> "trad...@optonline.net" wrote:
> > Here's a question no one has asked. Why is the meter
> > in a box that is locked? I've never seen this before.
>
> That question was posed earlier in this thread, and I speculated as to
> the reason for a locked cabinet in a post I made on Friday night (8:47
> pm est):
>
> ============
> The meter is in a locked cabinet. The only time I get to see it is when
> the meter-reader guy comes around once a month to read it.
>
> I suspect the meter is in a locked cabinet to prevent tampering / bypass
> (the meter is inside the utility / furnace room of the building and is
> not accessible from the outside).
> ==========
>
> Based on the following (and others which I'm not including) I don't
> think it's uncommon for billing meters to be located in locked cabinets,
> or "cupboards" (a term used in the UK):
>
>
> Multiple occupancy premises must have their meters readily accessible at
> all times and comply with section 6 of the WAER, unless remote reading
> facilities are installed. Where meters are located within a locked
> meter-box/ cabinet or enclosed area, an approved Horizon Power master
> lock must be fitted, allowing Horizon Power access to the meters at all
> times. The disengaging of electronic security systems to obtain access
> to the meters is not acceptable. Such cases will require an automated
> reading system (AMR) to be installed.
> ====================
>
Seems a bit extreme. That says that the power company would
need not only a key to the meter box, but also a key to the business
to get inside anytime they want. A situation that would seem
to expose them to all kinds of potential security issues.
It also doesn't say that YOU cannot have a key as well.
Regardless of what is happening in other places, many
of them in other countries as outlined below,
have you asked the electric
company if you can have a key?
> See also:
>
> http://forums.moneysavingexpert.com/showthread.php?t=2207277
>
> And this:
>
> ==================http://thestar.com.my/news/story.asp?file=/2011/5/21/sarawak/8727246&...
>
> See explained that Lee’s electricity meter was locked inside a
> centralised cabinet outside his premises and three of the eight meters
> inside the cabinet were found with signs of attempted tampering.
> ===================
>
> And this:
>
> =================http://forums.whirlpool.net.au/archive/1414092
>
> I live in a small townhouse block with 3 dwellings. We are in an Energy
> Australia distribution area.
>
> Our electricity meters are all together in a locked metal cabinet near
> the street. These connect with underground wiring to a breaker box in
> each house's garage.
> ==================
>
> And this:
>
> ===============http://www.theanswerbank.co.uk/Law/Question512492.html
Tony Hwang
Hi,
Often saw in my working days, meter inside a box but it always had an
opening(window) so one can see the reading and so on.
RBM
<gree...@neo.rr.com> wrote in message
news:hkm4u61jb56u660oj...@4ax.com...
** The point being, if you are totally ignorant as to how the dollar amount
on the electric bill is determined, the first place to ask questions is the
company supplying the electricity and providing the bill. Once you get all
those nasty details figured out, you'll have a better idea of how to go
about verifying the numbers
Ed Pawlowski
"Home Guy" <Ho...@Guy.com> wrote
> Poor every future poster to any newsgroup that asks a simple technical
> question and gets told by the peanut gallery that it's important to know
> all the ancilliary circumstances surrounding the question when in
> reality in the end those circumstances have no bearing on the question
> or it's answer.
I'd agree with you if you were right, but in all likelihood, you are not.
I've been hanging around USENET for about 15+ years now. I've seen too many
question asked, answered, and later find that the real answer is something
far different because important facts were left out.
k...@att.bizzzzzzzzzzzz
>
>"Home Guy" <Ho...@Guy.com> wrote
>> harry wrote:
>>
>>> > Does a "demand meter" give a more accurate measure of energy
>>> > consumption?
>>
>> (I note that no explicit answer is given for that question)
>
>The accuracy is the same range as any other meter.
>
>
>>
>>> It only shows the maximum. Usually they only show peaks that
>>> last a few minutes
>>> The purpose of a demand meter is to discourage the electric
>>> consumer from high peaks in demand. Usually there is an
>>> additional charge that depends on this peak.
>>
>> So are you saying that customers with "demand meters" are billed on the
>> basis of their peak demand - a reading based on only a few minutes worth
>> of energy usage as seen over an entire billing period?
>
>
>There is some confusion here. Power factor then is the ratio of active
>power to total power.
Specifically the ratio of real power to real+imaginary power. ;-)
> Power factor comes into play, mostly when you have a lot of large motors.
If the motors are fully loaded the PF will be close to one. A lot of unloaded
motors will have a low PF, as will a pile of electronics (specifically ones
with switching regulators), but for different reasons. Capacitors will
correct the former but will do nothing for the latter.
>Yes, you set the reading during startup with the inefficient motors.
No, that's real power being used.
>You
>can correct this by using a bank of capacitors properly sized. Or with a
>capacitor at each of the large users, such as a 150 HP air compressor.
Capacitors do nothing for start-up currents.
>I don't claim to understand it all, but I do know it exists.
>http://en.wikipedia.org/wiki/Power_factor
>http://www.myronzucker.com/calmanualpg1.html
>>
>
>> How is that a fair or equitable way to bill a customer?
>Questionable, but done all the time.
Not questionable at all. It makes perfect sense for large customers, as does
charging for power factor. None of this has anything to do with the OP's
problem, if he really has one, though.
Home Guy
> > Poor every future poster to any newsgroup that asks a simple
> > technical question and gets told by the peanut gallery that
> > it's important to know all the ancilliary circumstances
> > surrounding the question when in reality in the end those
> > circumstances have no bearing on the question or it's answer.
>
> I'd agree with you if you were right, but in all likelihood,
> you are not.
In this case, I'm asking how a watt calculation made by taking an
average RMS reading for a few minutes from a clamp-on RMS amp meter on a
supply phase and multiplying that by 120 to get VA would differ from the
"watts in use" as being measured by the utility's billing meter during
the same few minutes.
The question did not involve the various uncertainties as to whether the
meter is employing "demand-meter" metering, or the uncertainties as to
whether or not extrapolating a few minutes of average current draw is
representative of an entire month's usage.
The answer, as posted by a few sane people who looked at the original
question and gave an actual answer, is that yes, VA can be considered as
equivalent to watts when all loads are resistive and power-factor is
unity (ie - 1).
To the extent that my facility's appliances, devices and equipment have
non-linear (ie inductive) loads, my measure of VA == watts *will* be an
over-estimate of what the meter is measuring during the time-frame of
the measurement.
That over-estimation will most likely not exceed 10% because the worst
offenders for having low power-factors are small fractional-hp electric
motors, for which I have two (one in each bathroom of this building as
ceiling ventilation fans) and for which I would estimate their use to be
perhaps 3 hours per day. In addition to those two fans, the building's
furnace has a 220 VAC furnace fan motor which I would estimate to be 3/4
to 1 hp and the daily usage (for the present time) to be 1 hour per day
or less.
> I've been hanging around USENET for about 15+ years now.
I've been using it since 1988 (that's about 23 years now).
> I've seen too many question asked, answered, and later
> find that the real answer is something far different
> because important facts were left out.
And I've also seen far too many questions asked and then the thread is
hijacked by others who want to take the question on a tangent because
they don't know how to answer the original question but instead feel a
compulsion to post something to prove they are worthy or relevant to the
group.
Home Guy
> > Power factor comes into play, mostly when you have a lot of large
> > motors.
>
> If the motors are fully loaded the PF will be close to one.
In actuality, the larger the motor, the greater will be it's power
factor.
Fractional HP motors (1/8, 1/4, 1/3, 1/2, etc) have low power factors
(37% to 66%).
Motors above a dozen hp have power factors of 85% or better.
gree...@neo.rr.com
Those motors are only better because they are usually sized properly
and are running near their rating. If you lightly load such a motor,
it still can draw a lot of current, but out of phase with the voltage.
Little real power is being used, but lots of VAs. Another way of
looking at it is a lightly loaded motor is acting like an inductor.
The more real mechanical load applied to the motor, the more real
electrical power is required. The motor looks more and more like a
resistor as the power reaches the design limits of the motor.
HeyBub
>
> So are you saying that customers with "demand meters" are billed on
> the basis of their peak demand - a reading based on only a few
> minutes worth of energy usage as seen over an entire billing period?
>
> How is that a fair or equitable way to bill a customer?
>
Because the cost to generate the electricity is small compared to the cost
to deliver the energy. The cost to deliver the energy, in turn, is
determined by the infrastructure needed (poles, transformers, generation
capability, etc.). A commercial customer with even a short peak demand may
require more infrastructure to support that demand than dozens of
residential customers.
Home Guy
So what would you consider or where would you place the threshold for
which demand metering should be used by a customer?
What monthly kwh usage would you consider "worthy" or significant enough
for an electricity supplier to use a demand meter to cover this
so-called significant cost of delivering this huge amount of brief peak
energy?
Would you consider, say, 2000 kwh? Would a single month's total usage
of 2000 kwh qualify a customer for a demand meter? Would 4 consecutive
months of 2000 kwh be the line-in-the-sand for putting a customer on a
demand meter?
http://www.nationalgridus.com/niagaramohawk/non_html/eff_elec-demand.pdf
Demand meters for such small users are total bullshit.
Anyone with a 100 amp, single-phase service that is using their service
at 50% for an entire month would tip the scale at a 4300 kwh bill.
Hardly what I'd call justified for utilizing 50% of the smallest
installable utility service.
How would you justify the infrastructure costs needed to supply such a
paltry service such that demand metering is needed?
dpb
...
> How would you justify the infrastructure costs needed to supply such a
> paltry service such that demand metering is needed?
On the basis that it the assertion that it's not generation but
transmission only that matters--it's both.
Given the restrictions on new generation facilities and tightening
regulation on existing, if there's any growth in demand there's getting
to be nowhere from which to get it.
Applying demand metering shifts (or at least increases) the interest of
the user that previously hasn't ever cared by the only really effective
behavior-changing device--the pocketbook.
--
k...@att.bizzzzzzzzzzzz
>HeyBub wrote:
>
>> > So are you saying that customers with "demand meters" are billed
>> > on the basis of their peak demand - a reading based on only a
>> > few minutes worth of energy usage as seen over an entire billing
>> > period?
>> >
>> > How is that a fair or equitable way to bill a customer?
>>
>>
>> Because the cost to generate the electricity is small compared to
>> the cost to deliver the energy. The cost to deliver the energy,
>> in turn, is determined by the infrastructure needed (poles,
>> transformers, generation capability, etc.). A commercial customer
>> with even a short peak demand may require more infrastructure to
>> support that demand than dozens of residential customers.
>
>So what would you consider or where would you place the threshold for
>which demand metering should be used by a customer?
>
>What monthly kwh usage would you consider "worthy" or significant enough
>for an electricity supplier to use a demand meter to cover this
>so-called significant cost of delivering this huge amount of brief peak
>energy?
It's not the monthly kWh usage that determines whether demand metering is used
or useful. It's the *peak* usage and when that peak occurs. The
infrastructure has to be built for the largest demand, not average. Where the
threshold is placed is a different matter for each power company.
>Would you consider, say, 2000 kwh? Would a single month's total usage
>of 2000 kwh qualify a customer for a demand meter? Would 4 consecutive
>months of 2000 kwh be the line-in-the-sand for putting a customer on a
>demand meter?
I don't believe any residential customers have demand metering, but I could be
wrong.
>http://www.nationalgridus.com/niagaramohawk/non_html/eff_elec-demand.pdf
>
>Demand meters for such small users are total bullshit.
Define "such small".
>Anyone with a 100 amp, single-phase service that is using their service
>at 50% for an entire month would tip the scale at a 4300 kwh bill.
>Hardly what I'd call justified for utilizing 50% of the smallest
>installable utility service.
You wouldn't have demand metering with a 100A service. ...at least not a
residential service.
Mark
<k...@att.bizzzzzzzzzzzz> wrote:
>
yes you might. APS in Arizona offers demand metering to residential
customers, (at least they did when I lived there)
The so called PEAK demand was based on the highest power used during
any 60 minute period over the billing period. With demand metering,
they lower the kWh rate but they charge you also for the peak. For
example, with standard billing you might pay $0.12 per kWh. With
demand billing you would pay $0.06 per kHW plus $5.00 per peak kWh.
So for example if I used 100kWh during and a peak of 5 kWh during the
month the charge would be $60 plus $25. If you are just a little
careful you can save a lot of money. If you are just a little
careless it can cost you a lot of money.
Also following this thread some of you seem to be mixing up power
factor and demand billing, they are two different things. Some
industrial billing plans bill by kWh, peak kWh AND power factor.
Mark
Robert Green
> On 5/29/2011 8:59 AM, Home Guy wrote:
> > harry wrote:
> >
> >>> Does a "demand meter" give a more accurate measure of energy
> >>> consumption?
> >
> > (I note that no explicit answer is given for that question)
>
> No. It's immaterial to the usage; only determines what the appropriate
> rate will be.
I wouldn't say it that way. It's very material in that (as you clarify) it
sets the rate for the usage. Just nit-picking to make it clear to the OP
that there are two very clearly different factors to consider in business
rates that are different from residential rates. A power blip that ended up
turning every device on simultaneously (a rare situation - except for X-10
users <g>) could be an extremely costly event. Why? Because peak demand
rates are set by the maximum power ever used during the metering period.
The OP could have easily changed the dynamics of his billing by plugging in
a couple of new space heaters at exactly the wrong time. That sort of event
could easily explain why the OP finds himself owing a lot more money than
last year even though the kWh used could be virtually identical.
> Again, that only will matter if you're actually on a
> demand-based billing (which, personally, I would doubt for a small
> office-type complex, but wouldn't be impossible).
I've learned (the very hard way) that with posters here from all over the
world, many of the things I thought were customary nation or world-wide are
just local quirks. (-:
> > So are you saying that customers with "demand meters" are billed on the
> > basis of their peak demand - a reading based on only a few minutes worth
> > of energy usage as seen over an entire billing period?
>
> Yes
>
> > How is that a fair or equitable way to bill a customer?
>
> What's "fair" got to do with it? :)
"Deserves got nothing to do with it" - Unforgiven
> It's owing to the fact that as another already posted, facilities have
> to be provided by the utility to handle the peak load; that costs more
> so they bill more. It's also an incentive to the customer to look at
> load-leveling techniques aggressively to cut their costs.
>
> > Are commercial customers that typically use between 2000 and 3000 kwh of
> > electricity per month normally considered as candidates for a demand
> > meter, or are they used for much higher usage customers?
>
> Generally, much higher.
>
> All you'll have to do is look at your bill and you'll know what the
> tariff schedule is.
>
> Again, you're looking in the wrong place here, first.
No, I beg to differ. I always feel much more comfortable encountering
service personnel and such knowing as much as I can learn elsewhere. I
believe the OP has learned a great deal from this thread and could get to
the point where an encounter isn't even necessary. His bill probably holds
the sad tale of a one time excursion into a higher rate zone that's cost him
big time. I'll bet he now becomes very aggressive managing his peak load.
I would suggest dropping $25 for a basic Kil-O-Wat plug in meter
http://www.newegg.com/Product/Product.aspx?Item=N82E16882715001
to measure the current draw of all his equipment. Then I'd figure out some
sort of switching interlock or timer system to insure that loads don't all
coincide.
> In all likelihood, the "problem" is _NOT_ in the metering but in either
> having an unknown or parasitic load, the "reading" not being actual
> reading but estimated until the "catch up" real reading at the beginning
> of the year or other explainable issue. The likelihood of your meter
> being in error is quite low for the explanation of the usage data you
> previously posted.
Which is why I recommend the Kil-O-Watt meter. You can measure each device
(except hard-wired ones) and get a true reading (wattage or V/A) of its
instantaneous power consumption or the consumption over a period of time.
A clamp meter is a good way to measure the items hardwired to the circuit
panel, but it's pretty lousy for determining wattage or power consumption
over time for stand-alone devices.
-
Bobby G.
Evan
>
> And I've also seen far too many questions asked and then the thread is
> hijacked by others who want to take the question on a tangent because
> they don't know how to answer the original question but instead feel a
> compulsion to post something to prove they are worthy or relevant to the
> group.
AND:
I have seen way too many people propose entirely stupid questions and
postulate insane methods to try and answer them...
Yet, those people, like yourself, keep coming back here and asking
their questions leaving out important material facts because the
person seeking an answer either didn't know such information was
important or had any bearing on the answer they desired or they
are asking something they are totally ignorant about... Getting
defensive about your question when people attempting to help you
by asking for clarification of certain aspects and more details
about your situation is a clear indication that you are asking for
the information for illicit purposes or are just plain trolling...
Feeling like you need to offer *correction* to people who reply
to your newsgroup posting when they offend some etiquette
guideline is just showing that you are too focused on the
format of the message rather than the content... Chill out...
I didn't know that in addition to being an expert on accounts
payable that you were also an internet psychologist -- good
to know...
~~ Evan
dpb
...
> No, I beg to differ. I always feel much more comfortable encountering
> service personnel and such knowing as much as I can learn elsewhere. I
> believe the OP has learned a great deal from this thread and could get to
> the point where an encounter isn't even necessary. His bill probably holds
> the sad tale of a one time excursion into a higher rate zone that's cost him
> big time. I'll bet he now becomes very aggressive managing his peak load.
...
I get no feeling OP has really learned a thing...it seems to all just
pass over as it doesn't fit into the preconceived notion.
His complaint is he has a few months w/ very high usage; not that the $
amount is high at relatively low total usage (as would be the symptom of
a demand-induced premium). I think the likelihood he actually has a
demand meter is very low.
From the numbers on usage he posted before, it appears to be a fairly
consistent usage w/ a couple of months extreme outliers. Both of those
are early in different years; my hypothesis is that the other months
are, for the most part, estimated rather than actually read and the one
annual blip is the catchup because they've not updated the average usage
to reflect actual since it was set up (probably before OP bought the
building).
--
Home Guy
> > Would you consider, say, 2000 kwh? Would a single month's total
> > usage of 2000 kwh qualify a customer for a demand meter? Would
> > 4 consecutive months of 2000 kwh be the line-in-the-sand for
> > putting a customer on a demand meter?
http://www.nationalgridus.com/niagaramohawk/non_html/eff_elec-demand.pdf
> Define "such small".
2000 kwh per month is "such small".
> > Anyone with a 100 amp, single-phase service that is using their
> > service at 50% for an entire month would tip the scale at a
> > 4300 kwh bill.
And 4300 is more than 2 x 2000.
> > Hardly what I'd call justified for utilizing 50% of the
> > smallest installable utility service.
>
> You wouldn't have demand metering with a 100A service.
Did you read the link?
A 100 amp service is 4 times what you need to draw 2000 kwh in a month.
Evan
wrote:
> "dpb" <n...@non.net> wrote in messagenews:irtksp$la2$1...@speranza.aioe.org...
@Bobby:
Or the OP could have an an electrician install an emon demon like
RBM suggested in his main service panel and the reading from it
and the amount of electricity the OP is being billed for should always
agree...
http://www.emon.com/index.html
~~ Evan
Evan
@Home Guy:
You are too focused on the total billed number of kWh to see why
a demand meter is used for electrical services with a main disconnect
rated over a certain amperage...
A customer with a steady draw (demand) of 2.7 KW over 30 days to
end up being billed for 2,000 kWh over the course of a billing period
is *MUCH* easier for a power company to serve than a customer
whose draw is 500 KW a couple of times during the same billing period
and winds up with the same 2,000 kWh of use...
To serve the second customer whose demand is erratic and might
come at a time when the local power grid is overloaded requires
the power company to provide beefier service lines in that area
and have the capacity to accommodate that erratic load without
tripping safety devices in the power grid or browning out other
customers...
You just don't seem to understand that the greater the amount
of power a customer needs to use at the same time (peak demand)
is more important than the total of the kWh that customer is billed
for during any given period... Whether you use 1 KW for 2,000 hours
or 2,000 KW for 1 hour makes a difference in how the power company
serves you as far as equipment and capacities...
Again whether or not you have a demand meter depends on the
purpose of the occupancy and the amperage rating of the main
disconnect... A home with a 100 or 200 amp main service would
usually not have a demand meter, but a home with a 1,200 amp
main disconnect very well might have a demand meter installed...
~~ Evan
Home Guy
> His bill probably holds the sad tale of a one time excursion
> into a higher rate zone that's cost him big time. I'll bet he
> now becomes very aggressive managing his peak load.
I've located some PDF documents that my local utility has on-line.
I have to have a "12-month average demand" equal to or more than 50 kW,
or have a 12-month rolling kwh consumption greater than 150,000 KWhrs in
order to have a demand meter. 150,000 kwhrs divided by 12 is 12,500 kwh
per month, which is about 4 times my average monthly consumption.
So no, I don't think I've experienced any one-time excursion into a
higher rate zone, at least not in terms of being demand-metered (if
indeed there are any other ways of entering a higher rate zone).
Smitty Two
>
> I get no feeling OP has really learned a thing...it seems to all just
> pass over as it doesn't fit into the preconceived notion.
Agree.
>
> His complaint is he has a few months w/ very high usage; not that the $
> amount is high at relatively low total usage (as would be the symptom of
> a demand-induced premium). I think the likelihood he actually has a
> demand meter is very low.
Here's an interesting page:
http://www.united-cs.com/demand.aspx
illustrating how peak demand can create a tenfold increase in cost.
Despite the OP's relatively low actual usage, the power coming into the
building is substantial. IIRC, 400 amps of 3-phase. Perhaps that
capability is what puts him in the demand category with the power
company. (The page referenced says all 3-phase users are billed that
way, but of course chances are OP is not in that particular service
area)
If the OP would stop believing that he already knows everything and
actually read the bill as has been suggested, or post it online if he's
incapable of understanding it, "more will be revealed."
k...@att.bizzzzzzzzzzzz
>"k...@att.bizzzzzzzzzzzz" wrote:
>
>> > Would you consider, say, 2000 kwh? Would a single month's total
>> > usage of 2000 kwh qualify a customer for a demand meter? Would
>> > 4 consecutive months of 2000 kwh be the line-in-the-sand for
>> > putting a customer on a demand meter?
>
>http://www.nationalgridus.com/niagaramohawk/non_html/eff_elec-demand.pdf
>
>> Define "such small".
>
>2000 kwh per month is "such small".
OK.
>> > Anyone with a 100 amp, single-phase service that is using their
>> > service at 50% for an entire month would tip the scale at a
>> > 4300 kwh bill.
>
>And 4300 is more than 2 x 2000.
Say it ain't so! That would be *highly* unusual and would not be an issue
with demand metering, now would it? <shakes head>
>> > Hardly what I'd call justified for utilizing 50% of the
>> > smallest installable utility service.
>>
>> You wouldn't have demand metering with a 100A service.
>
>Did you read the link?
Yes, did you? It talks about residential customers not having demand
metering.
>A 100 amp service is 4 times what you need to draw 2000 kwh in a month.
Good grief, you're stupid!
k...@att.bizzzzzzzzzzzz
Isn't it a TIME metering (usage in peak times is metered differently than
off-peak times)? Peak metering on such small loads would be dumb.
>The so called PEAK demand was based on the highest power used during
>any 60 minute period over the billing period. With demand metering,
>they lower the kWh rate but they charge you also for the peak. For
>example, with standard billing you might pay $0.12 per kWh. With
>demand billing you would pay $0.06 per kHW plus $5.00 per peak kWh.
>So for example if I used 100kWh during and a peak of 5 kWh during the
>month the charge would be $60 plus $25. If you are just a little
>careful you can save a lot of money. If you are just a little
>careless it can cost you a lot of money.
Yes, we've already discussed all that. Ad-nauseam.
>Also following this thread some of you seem to be mixing up power
>factor and demand billing, they are two different things. Some
>industrial billing plans bill by kWh, peak kWh AND power factor.
You're not following this thread, then. People are trying to figure out what
is causing the moron OP to run around with his hair on fire.
Home Guy
> Despite the OP's relatively low actual usage, the power coming
> into the building is substantial.
What a joke.
The "power coming into the building" can be no more than the power being
used by the building's equipment, devices or appliances.
That fact that I've got some high-rated switch gear and primary supply
wire shouldn't play a role in how I'm billed. It's still a basic
3-phase 120/208 supply. Nothing fancy.
Home Guy
> > 2000 kwh per month is "such small".
>
> OK.
So you agree that 2000 kwh is a pittance.
> > Did you read the link?
>
> Yes, did you? It talks about residential customers not having
> demand metering.
So what?
Why should any utility put a demand meter on anyone pulling only 2000
kwh per month?
> > A 100 amp service is 4 times what you need to draw 2000 kwh
> > in a month.
>
> Good grief, you're stupid!
If that statement is incorrect, then you tell us how many kwh a 100 amp
single phase service can provide in a month (730 hours in a month, btw).
k...@att.bizzzzzzzzzzzz
>"k...@att.bizzzzzzzzzzzz" wrote:
>
>> > 2000 kwh per month is "such small".
>>
>> OK.
>
>So you agree that 2000 kwh is a pittance.
I agree that you're a moron, but I'm certainly not alone here.
>> > Did you read the link?
>>
>> Yes, did you? It talks about residential customers not having
>> demand metering.
>
>So what?
>
>Why should any utility put a demand meter on anyone pulling only 2000
>kwh per month?
They certainly didn't. Why do you insist they did?
>> > A 100 amp service is 4 times what you need to draw 2000 kwh
>> > in a month.
>>
>> Good grief, you're stupid!
>
>If that statement is incorrect,
It's not, but that doesn't change the fact that you're stupid as a stump.
>then you tell us how many kwh a 100 amp
>single phase service can provide in a month (730 hours in a month, btw).
It might be correct, but completely irrelevant. Unless your power company (or
PUC) is totally whacked, you wouldn't have demand metering with such a puny
service.
Now, why don't you listen to the people you're asking question of? Or put
another way, why did you ask if you don't want the answer?
Smitty Two
> Smitty Two wrote:
>
> > Despite the OP's relatively low actual usage, the power coming
> > into the building is substantial.
>
> What a joke.
>
> The "power coming into the building" can be no more than the power being
> used by the building's equipment, devices or appliances.
Let me rephrase, perhaps you'll like this better, Mr. Semantic Pedantic:
Your building has a 400 amp 3-phase SERVICE. That's what I mean by "the
power coming into the building." I don't care if you're all huddled
around a transistor radio and a candle, you still have an industrial
level of service to your building. THAT is a good reason for the utility
to put you on demand metering or apply a host of other charges that
those with smaller services would not incur.
>
> That fact that I've got some high-rated switch gear and primary supply
> wire shouldn't play a role in how I'm billed. It's still a basic
> 3-phase 120/208 supply. Nothing fancy.
Uh-huh. You gonna attend the next PUC meeting and speak up about how you
think the electric company "should" behave?
harry
> harry wrote:
> > > Does a "demand meter" give a more accurate measure of energy
> > > consumption?
>
> (I note that no explicit answer is given for that question)
>
> > last a few minutes
> > The purpose of a demand meter is to discourage the electric
> > consumer from high peaks in demand. Usually there is an
> > additional charge that depends on this peak.
>
> basis of their peak demand - a reading based on only a few minutes worth
> of energy usage as seen over an entire billing period?
>
> How is that a fair or equitable way to bill a customer?
>
> electricity per month normally considered as candidates for a demand
> meter, or are they used for much higher usage customers?
Don't you know the meaning of "additional"?
Whether you get a demand meteror not depends on how near to the
knuckle the electricity system is being run locally. And on the
companies billing policy.
Tony Hwang
Hi,
Is that 3-ph. Delta or Star configured? So many were talking about Pf
and still you talk like that? I resigned, over and out. It may be easier
to tech my cat.
Robert Green
I'd agree that according to the documents it's unlikely you have a demand
meter BUT mistakes happen and they may be basing YOUR billing on some
previous occupant of the premises who may have indeed been operating a
business that used far more electricity that you currently use.
I do stand my by statement that if and when you contact them, you'll be in a
much better position, knowledge-wise, to determine whether what they are
saying is truthful. I once had to take the gas company to the public
service commission because they simply decided I must be cheating because my
gas usage had dropped so much in one year (I switched to a few space heaters
since I was living in primarily one room, recovery from surgery). Why pay
to heat the rest of the house when I was only using one room?
They were such assholes about it that I now wouldn't trust them or the
electric company with a burned out match. The PSC reversed their decision
to bill be for gas I "should have used" because if the meter had failed, it
was the company's fault, not mine. It was a unpleasant experience that
taught me that those who say "the power company" rarely makes mistakes just
haven't had any problems with their utilities - yet.
So good luck to you Home Guy. I believe it's never wrong to question
something you think is way out of line and to learn all you can about the
issue before contacting those in authority. Obviously loads of other people
here believe differently, but they are informed by different experiences.
My experience is that utilities CAN and DO make serious mistakes, and when
they do, they often try to cover up their incompetence or worse, even if it
costs some poor guy like you or me $100's or $1,000's.
It's too bad much of this thread devolved into a typical Usenet pissing
match, but remember, there's never a shortage of Usenet posters who live
just to get people's goats by posting that "everything you do is wrong and
you're an idiot." Except they usually spell it "your an idiot." Learning
not to respond to "goat getters" is one of the many tests of manhood that
Usenet offers. (-:
Good luck. I hope you sort this out. Something looks fishy.
--
Bobby G.
The Ghost in The Machine
<k...@att.bizzzzzzzzzzzz> wrote:
> On Sat, 28 May 2011 15:21:47 -0500, Jim Yanik <jya...@abuse.gov> wrote:
> >"RBM" <r...@live.com> wrote innews:4de064ae$0$7953$607e...@cv.net:
>
> >> "Mark" <makol...@yahoo.com> wrote in message
> >>news:aceeb9d6-2cfb-40b1...@w36g2000vbi.googlegroups.com...
> >> On May 27, 8:47 pm, Home Guy <H...@Guy.com> wrote:
> >>> RBM used improper usenet message composition style by full-quoting:
>
> >>> > > 3) There are (on average) 30.4 days in a month, and therefore 730
> >>> > > hours in a month. If I take the above wattage calculation (120 x
> >>> > > total_current) and multiply it by 730, then divide by 1000, I
> >>> > > should get a quantity energy measurement (KWh) that should match
> >>> > > (or approximate) my bill from the local utility - assuming that
> >>> > > the load in use at the time of the readings are representative of
> >>> > > daily or continuous use. If this method of obtaining a
> >>> > > representative monthly KWh measurement is not correct (or needs
> >>> > > more refinement) then please state what, why or how.
>
> >>> > **You're not going to be the least bit accurate trying to calculate
> >>> > that way.
>
> >>> I want to establish several use-case situations, primarily a
> >>> "worst-case" KWh monthly usage by assuming that all the devices that are
> >>> normally on during a week-day 9-am to 5-pm work day and turned off at
> >>> all other times are instead left on continuously 24/7.
>
> >>> I can also get current readings for other use-case situations (evenings
> >>> and week-ends) that should give me a more closer-to-reality current
> >>> reading and factor in their time-of use over the course of a month.
>
> >>> This is a small office - not a home. There are fewer variable involved.
>
> >>> > There is no reason that you shouldn't be able to look at the
> >>> > electric meter.
>
> >>> The meter is in a locked cabinet. The only time I get to see it is when
> >>> the meter-reader guy comes around once a month to read it.
>
> >>> I suspect the meter is in a locked cabinet to prevent tampering / bypass
> >>> (the meter is inside the utility / furnace room of the building and is
> >>> not accessible from the outside).
>
> >>> And besides, having the ability to lay my eyes on the meter won't tell
> >>> me anything about the accuracy of the meter, or the real-time current
> >>> consumption.
>
> >>> All I want to know is - should the current readings from a clamp-on
> >>> meter (when extrapolated across the 730 hours of a typical month) jive
> >>> with the accumulated KWh reading as measured by a typical billing
> >>> meter? Do I have to do any "special" math to the wattage I calculate
> >>> with the meter to arrive at what the billing meter is measuring?
>
> >> yes you are correct you can get a rough reading this way..
> >> you need to measure and sum only the 3 black cables, do not include
> >> the white striped cable in the sum.
>
> >> Add up the 3 currents and multiply by 120 and this is your VAs and the
> >> actual Watts will be equal to or less then the VAs.
>
> >> Multiply by hours and you have Watt Hours.
>
> >> Divide by 1000 and you have kWh which is how you are billed.
>
> >> Mark
>
> >> This is a commercial service and metering equipment. How is he going to
> >> guestimate demand?
>
> >since the white return wire returns the current from all 3 phases,wouldn't
> >that give you the sum of all the currents?
>
> Only the *difference* of the three phases is returned in the neutral. With a
> balanced load there will be zero current in the neutral.
>
YOU ARE ALL SO FULL OF HOOEY.....THE ABOVE STATEMENT IS INCORRECT.
ON SAID NEUTRAL THERE WILL BE A POTENTIAL TO GROUND EQUAL TO THE
LOAD....
KRW YOU ARE ONE DUMBASS ENDANGERING MOTHERFUCKER.
I HAVE COME TO TNE CONCLUSION THAT THOUGH SOME OF YOU ARE VERSED AND
EDUCATED YOUR OBSERVATIONS AND KNOWLEDGE IS WANDERING...RENDERING
THESE GROUPS USELESS, MISGUIDING AND NOT WORTH THE EFFORT PUT INTO
THEM...
PATECUM
TGITM