Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
House Electrical Circuit: Leakage?
11 views
Skip to first unread message
(PeteCresswell)
Jan 7, 2013, 10:44:33 AM1/7/13
to
Recently installed a generator cutover switch
(http://tinyurl.com/a6e9fgn) which tells me how much each circuit
is drawing.
I have one circuit which, when I *think* everything is unplugged,
still draws 18 watts.
First thing that comes to mind is that the circuit is serving
something that I do not know about; but I am hard-pressed to find
it.
That seems to leave "Leakage".
Is there any such thing as an electrical leak in home wiring?
If so, typical causes? Location strategies?
--
Pete Cresswell
(http://tinyurl.com/a6e9fgn) which tells me how much each circuit
is drawing.
I have one circuit which, when I *think* everything is unplugged,
still draws 18 watts.
First thing that comes to mind is that the circuit is serving
something that I do not know about; but I am hard-pressed to find
it.
That seems to leave "Leakage".
Is there any such thing as an electrical leak in home wiring?
If so, typical causes? Location strategies?
--
Pete Cresswell
Neon John
Jan 7, 2013, 11:16:06 AM1/7/13
to
There can be leakage but not the type you're thinking of. Romex has
capacitance between the hot and ground wire and to a lesser extent, to
the neutral. It is insulated with a high dielectric loss (PVC)
insulation. Thus, some small amount of real power dissipation will be
consumed per foot heating the cable even when there is no load. If
the runs are long that could amount to a few watts.
Do you have a doorbell transformer? It probably dissipated 4 or 5
watts just sitting there.
Is your furnace/heat pump on the circuit? If so, there's a control
transformer that also will consume a few watts unloaded.
Finally, the is the question of near-zero-indication accuracy of the
meter. I see from the specs that the input spec is 30 amps.
Presumably the current transducer is rated for at least 30 amps and
probably 50. 14 watts would be 14/120 volts = 0.116 amps. That is
0.116/50 = 0.233 percent of full scale on the transducer. That's not
figuring in the tolerance of the voltage transducer. The CT is likely
to be a 1 or maybe 0.5% part. So that 14 watt reading could be
literally nothing.
One way to check is to open all the breakers. What does the wattmeter
say? Now close in the breakers, one at a time and see what happens.
If the reading develops when you close a breaker then you know that
it's real. Remember that an indication that low is way outside the
tolerance of the metering element so it might be 1 watt or 20 watts or
??? If it really is 14 watts then that's enough power dissipation
that you should be able to find something warm to the touch on that
circuit.
John
On Mon, 07 Jan 2013 10:44:33 -0500, "(PeteCresswell)" <x...@y.Invalid>
wrote:
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address
capacitance between the hot and ground wire and to a lesser extent, to
the neutral. It is insulated with a high dielectric loss (PVC)
insulation. Thus, some small amount of real power dissipation will be
consumed per foot heating the cable even when there is no load. If
the runs are long that could amount to a few watts.
Do you have a doorbell transformer? It probably dissipated 4 or 5
watts just sitting there.
Is your furnace/heat pump on the circuit? If so, there's a control
transformer that also will consume a few watts unloaded.
Finally, the is the question of near-zero-indication accuracy of the
meter. I see from the specs that the input spec is 30 amps.
Presumably the current transducer is rated for at least 30 amps and
probably 50. 14 watts would be 14/120 volts = 0.116 amps. That is
0.116/50 = 0.233 percent of full scale on the transducer. That's not
figuring in the tolerance of the voltage transducer. The CT is likely
to be a 1 or maybe 0.5% part. So that 14 watt reading could be
literally nothing.
One way to check is to open all the breakers. What does the wattmeter
say? Now close in the breakers, one at a time and see what happens.
If the reading develops when you close a breaker then you know that
it's real. Remember that an indication that low is way outside the
tolerance of the metering element so it might be 1 watt or 20 watts or
??? If it really is 14 watts then that's enough power dissipation
that you should be able to find something warm to the touch on that
circuit.
John
On Mon, 07 Jan 2013 10:44:33 -0500, "(PeteCresswell)" <x...@y.Invalid>
wrote:
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address
Jim Wilkins
Jan 7, 2013, 12:21:57 PM1/7/13
to
"(PeteCresswell)" <x...@y.Invalid> wrote in message
news:p4rle8ludgptn6fe8...@4ax.com...
Doorbell or old Princess telephone transformer? It would likely be on
a junction box cover rather than plugged into an outlet.
news:p4rle8ludgptn6fe8...@4ax.com...
a junction box cover rather than plugged into an outlet.
Jim Wilkins
Jan 7, 2013, 1:15:05 PM1/7/13
to
"Neon John" <n...@never.com> wrote in message
news:uasle8tch6drutauu...@4ax.com...
That's a very good point, so I checked two connected 100' extension
cords with neon bulbs in their sockets on a P4460 KAWez. The readings
were 0.00A, 0.0W.
jsw
news:uasle8tch6drutauu...@4ax.com...
> There can be leakage but not the type you're thinking of. Romex has
> capacitance between the hot and ground wire and to a lesser extent,
> to
> the neutral. It is insulated with a high dielectric loss (PVC)
> insulation. Thus, some small amount of real power dissipation will
> be
> consumed per foot heating the cable even when there is no load. If
> the runs are long that could amount to a few watts.
>
> John DeArmond
> capacitance between the hot and ground wire and to a lesser extent,
> to
> the neutral. It is insulated with a high dielectric loss (PVC)
> insulation. Thus, some small amount of real power dissipation will
> be
> consumed per foot heating the cable even when there is no load. If
> the runs are long that could amount to a few watts.
>
That's a very good point, so I checked two connected 100' extension
cords with neon bulbs in their sockets on a P4460 KAWez. The readings
were 0.00A, 0.0W.
jsw
mike
Jan 7, 2013, 2:33:59 PM1/7/13
to
Still 14 VA is a lot for a disconnected circuit.
Did you actually disconnect the wire? AKA "where does
the transfer switch get power?
Doorbell? Burglar Alarm? Garage door opener?
turn off the suspect breaker and see if they all still work.
You can break the circuit at any wall plate.
Half-interval search method should get you there in few tries.
danny burstein
Jan 7, 2013, 2:39:45 PM1/7/13
to
[snip]
any motion detector lights? cable/sateliite tv box?
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
any motion detector lights? cable/sateliite tv box?
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
Vaughn
Jan 7, 2013, 6:11:38 PM1/7/13
to
On 1/7/2013 12:21 PM, Jim Wilkins wrote:
> Doorbell...transformer? It would likely be on
living in this old house for 25 years and still haven't stumbled across
mine. Yet the doorbell works.
When that hidden transformer finally goes bad, I hope it's an open
primary and not shorted turns.
Vaughn
> Doorbell...transformer? It would likely be on
> a junction box cover rather than plugged into an outlet.
They stick doorbell transformers in the strangest places. I've been
living in this old house for 25 years and still haven't stumbled across
mine. Yet the doorbell works.
When that hidden transformer finally goes bad, I hope it's an open
primary and not shorted turns.
Vaughn
T. Keating
Jan 8, 2013, 11:58:52 AM1/8/13
to
On Mon, 07 Jan 2013 10:44:33 -0500, "(PeteCresswell)" <x...@y.Invalid> wrote:
(tripped or active will make no difference.)
There is not very much you can do about it, since building code requires them for certain
locations.
Other leakage... Clocks on appliances, doorbell, transformer powering thermostat, power
line modules(x-10), etc..
Jim Wilkins
Jan 8, 2013, 12:43:05 PM1/8/13
to
"T. Keating" <tkus...@ktcnslt.com> wrote in message
news:mnjoe8pk6rgcr3bsd...@4ax.com...
jsw
news:mnjoe8pk6rgcr3bsd...@4ax.com...
>
> Each GFI(outlet or breaker) or Arc-fault breaker will consume a
> couple of watts per unit.
> (tripped or active will make no difference.)
>
Another good point. A single-outlet plug-in GFCI here draws 1.4W.
> Each GFI(outlet or breaker) or Arc-fault breaker will consume a
> couple of watts per unit.
> (tripped or active will make no difference.)
>
jsw
j
Jan 8, 2013, 2:41:50 PM1/8/13
to
1$/W or $1.40 for that single GFCI. I have 5 of them, so $7/yr.
How did you come up with the draw so quick?
(copy sent to OP by accident)
Jeff
> jsw
>
>
Jim Wilkins
Jan 8, 2013, 5:29:04 PM1/8/13
to
"j" <mun...@att.net> wrote in message
news:kchspb$l5r$1...@news.albasani.net...
> Jeff
I'll spare you a quick-draw joke.
http://www.p3international.com/products/p4460.html
news:kchspb$l5r$1...@news.albasani.net...
I'll spare you a quick-draw joke.
http://www.p3international.com/products/p4460.html
(PeteCresswell)
Jan 9, 2013, 10:16:42 AM1/9/13
to
Per mike:
That circuit was one of the two circuits that power the transfer
switch.
Swapped it over to another circuit and the "leakage" went away.
Thanks!... I never would have thought of that.
--
Pete Cresswell
>
>Did you actually disconnect the wire? AKA "where does
>the transfer switch get power?
Bingo!
>Did you actually disconnect the wire? AKA "where does
>the transfer switch get power?
That circuit was one of the two circuits that power the transfer
switch.
Swapped it over to another circuit and the "leakage" went away.
Thanks!... I never would have thought of that.
--
Pete Cresswell
Jim Wilkins
Jan 9, 2013, 4:29:22 PM1/9/13
to
No, the KAW doesn't measure the draw of the socket it's plugged into,
GFCI or standard. I plugged a stand-alone, plug-in GFCI into the KAW.
Pete C.
Jan 9, 2013, 5:52:21 PM1/9/13
to
g
Jan 10, 2013, 11:20:49 AM1/10/13
to
On 07/01/2013 15:11, Vaughn wrote:
> On 1/7/2013 12:21 PM, Jim Wilkins wrote:
>> Doorbell...transformer? It would likely be on
>> a junction box cover rather than plugged into an outlet.
>
> They stick doorbell transformers in the strangest places.
In my old house they fixed the transformer onto the service panel. You
> On 1/7/2013 12:21 PM, Jim Wilkins wrote:
>> Doorbell...transformer? It would likely be on
>> a junction box cover rather than plugged into an outlet.
>
> They stick doorbell transformers in the strangest places.
cannot see it unless you take off the front cover...
//g
0 new messages