(In US) Tap 240V dryer outlet to make 120V outlet?
Harlan Messinger
We're replacing our electric clothes dryer with a gas model, so we
need a 120V receptacle instead of the existing 240V. I'd like to leave
the 240V circuit there for possible future use. I understand the
general precautions involved in home wiring and the mechanics of
running an extension from the 240V box to a new 120V box (one hot
wire, the neutral, and the ground), but I was wondering if there is
any reason NOT to do what I propose or whether there are any special
precautions I might have overlooked.
Thanks in advance.
Michel Gagnon
In article <4oci58$3...@clarknet.clark.net>, gu...@clark.net (Harlan
Messinger) wrote:
In most cases, the U.S. code requires only a 2 wire + ground connection
for an electric dryer; therefore, there are only two hot wires and no
neutral around. Besides, it is generally forbidden to place wires from two
different electrical circuits in the same box, unless there is a metal
separator in between (like two boxes sharing one common wall.
On top of that, I am not aware of the power requirement of a gas dryer. It
might be possible to share one single 15 A ciruit with the washing
machine, but you most likely need separate circuits for the washing
machine and the dryer. I also don¹t know if U.S. Code considers these as
"small appliance" 20 A circuits (like kitchen ones) or general 15 A
circuits.
One easy solution, without any major rewiring, is this:
- Shut off the mains, and change the existing 30 A double-pole breaker
(for electric dryer) by two individual 15 A breakers (or one 15 A and one
20 A if gas dryer needs to be on 20 A in the U.S.).
- If, as most likely, the cable to the dryer is a 10/2 (i.e. two wires +
ground), connect the black wire to the 15 A (or 20 A, see above) and
connect the other wire to the neutral bus. If, by any chance, the other
wire is red, you should colour it white (with electrical tape, for
example).
- If the dryer cable is a 10/3 (like in Canada -- or in U.S. when it
comes from a subpanel), the white wire should already be connected to the
neutral bus. Just take away the unused red wire (from the former breaker)
and put a connector to isolate its end; leave it there for future
reconversion.
- At the other end, install a 120 V 15 A (or 20 A) plug in lieu of the
existing electric dryer plug. There are special adaptor plates that enable
the use of a standard receptacle in a 4 in box. You will need to pigtail
the #10 wires to short sections of #12 wires, as it is impossible to screw
#10 wires onto standard plugs. You should also colour-code the red wire
into white, or, if it is 10/3, terminate properly the now unused red wire.
P.S. The other 15 A breaker is unused -- reserved for future use, should
you install another circuit with new cable... It is a decent way to safely
cover a hole in the panel.
Good luck!
(posted and mailed)
Michel Gagnon -- Montréal (Québec, Canada)
mga...@accent.net
gya...@netcom.ca
gu...@clark.net (Harlan Messinger) wrote:
>We're replacing our electric clothes dryer with a gas model, so we
>need a 120V receptacle instead of the existing 240V. I'd like to leave
>the 240V circuit there for possible future use. I understand the
>general precautions involved in home wiring and the mechanics of
>running an extension from the 240V box to a new 120V box (one hot
>wire, the neutral, and the ground), but I was wondering if there is
>any reason NOT to do what I propose or whether there are any special
>precautions I might have overlooked.
>Thanks in advance.
The obvious one is that your new receptacle is a 15 Ampere device
and you are probably going to extend the circuit with wire rated 15 Amperes,
but the dryer circuit protection, either fuse or breaker, is likely 30 Amps so
it won't protect anything downstream from the old receptacle.
All you have to do is change the protection to 15 Ampere.
Gord Yanow
Calvin Henry-Cotnam
gya...@netcom.ca (gya...@netcom.ca) said...
>
>gu...@clark.net (Harlan Messinger) wrote:
>
>>We're replacing our electric clothes dryer with a gas model, so we
>>need a 120V receptacle instead of the existing 240V. I'd like to leave
>>the 240V circuit there for possible future use. I understand the
>>general precautions involved in home wiring and the mechanics of
>>running an extension from the 240V box to a new 120V box (one hot
>>wire, the neutral, and the ground), but I was wondering if there is
>>any reason NOT to do what I propose or whether there are any special
>>precautions I might have overlooked.
>
>
>and you are probably going to extend the circuit with wire rated 15 Amperes,
>but the dryer circuit protection, either fuse or breaker, is likely 30 Amps
so
>it won't protect anything downstream from the old receptacle.
>
>All you have to do is change the protection to 15 Ampere.
That would be fine if one were doing away with the 240 volt outlet,
but the original poster wishes to keep the 240 volt outlet intact
for a possible future need.
One way to accomplish this would be to add a small single fuse/breaker
box off one leg of the 240 volt/30 amp dryer outlet that feeds the
120 volt/15 amp outlet. This will provide the necessary protection for
the lower-rated outlet while keeping the higher-rated outlet intact for
future use.
--
Calvin Henry-Cotnam, CATE | "Spare the duct tape,
Ryerson Polytechnic University | spoil the job."
Toronto, Ontario, Canada | - Red Green
george
:That would be fine if one were doing away with the 240 volt outlet,
:but the original poster wishes to keep the 240 volt outlet intact
:for a possible future need.
:
:One way to accomplish this would be to add a small single fuse/breaker
:box off one leg of the 240 volt/30 amp dryer outlet that feeds the
:120 volt/15 amp outlet. This will provide the necessary protection for
:the lower-rated outlet while keeping the higher-rated outlet intact for
:future use.
may be easier to hook up the new outlet with receptacle and wire
rated for 30amps.. Problems with this?
--
george
geo...@mech.seas.upenn.edu
Dwa...@mddc.com
In article <4oci58$3...@clarknet.clark.net>, gu...@clark.net (Harlan
Messinger) wrote:
> We're replacing our electric clothes dryer with a gas model, so we
> need a 120V receptacle instead of the existing 240V. I'd like to leave
> the 240V circuit there for possible future use. I understand the
> general precautions involved in home wiring and the mechanics of
> running an extension from the 240V box to a new 120V box (one hot
> wire, the neutral, and the ground), but I was wondering if there is
> any reason NOT to do what I propose or whether there are any special
> precautions I might have overlooked.
>
> Thanks in advance.
It would work fine but you should change to a lower amperage breaker
because the cords or the gas dryer are probably not rated for the higher
amperage of the electric dryer circuit. Elec. dryers are generally 30 amp
and the gas dryer probably needs 15 or 20 amps. Using the 30 amp (or
larger) could pose a fire hazard in the event of a short circuit.
Dwayne
Sam Goldwasser
> We're replacing our electric clothes dryer with a gas model, so we
> need a 120V receptacle instead of the existing 240V. I'd like to leave
> the 240V circuit there for possible future use. I understand the
> general precautions involved in home wiring and the mechanics of
> running an extension from the 240V box to a new 120V box (one hot
> wire, the neutral, and the ground), but I was wondering if there is
> any reason NOT to do what I propose or whether there are any special
> precautions I might have overlooked.
If your dryer has a 3 prong plug, then you only have the two hot wires
and ground/neutral. The separate hot and neutral wirss required for a
properly connected 120 V outlet are not available without running an
additional line from the service panel.
If it has 4 wires, then extending one H and the N and G to a new outlet
should not be a problem.
--- sam
> Thanks in advance.
gya...@netcom.ca
gu...@clark.net (Harlan Messinger) wrote:
>We're replacing our electric clothes dryer with a gas model, so we
>need a 120V receptacle instead of the existing 240V. I'd like to leave
>the 240V circuit there for possible future use. I understand the
>general precautions involved in home wiring and the mechanics of
>running an extension from the 240V box to a new 120V box (one hot
>wire, the neutral, and the ground), but I was wondering if there is
>any reason NOT to do what I propose or whether there are any special
>precautions I might have overlooked.
>Thanks in advance.
Oops! When I suggested that the only problem was that your protection
was too high for the 15 Amp receptacle, I should have mentioned that
I am Canadian and this is a U.S. question. There could be some state
or municipal rule that might cause problems which I would not be aware of.
Sorry. Otherwise, the Ontario Hydro Electrical Safety Code and CSA are
much more demanding than any U.S.rules that I know of. I know because
I have had to modify equipment imported from the U.S..
Gord Yanow
Calvin Henry-Cotnam
george (je...@red.seas.upenn.edu) said...
There are if you do not change the *protection* to 15 amps. The new
appliance has a plug that is rated for 15 amps and must plug into
a receptacle rated for 15 amps (or one for 20 amps, in the US).
Using heavier wire is no problem at all, other than cost, but that is not
an issue as the heavier wire is already in place.
My suggestion was for the situation where one wanted to preserve the
240V/30A outlet and provide a 120V/15A outlet. Changing the breaker
and the receptacle is probably the easiest, but returning to the original
configuration requires changing both back again.
kent...@cns.nyu.edu
>We're replacing our electric clothes dryer with a gas model, so we
>need a 120V receptacle instead of the existing 240V. I'd like to leave
>the 240V circuit there for possible future use. I understand the
>general precautions involved in home wiring and the mechanics of
>running an extension from the 240V box to a new 120V box (one hot
>wire, the neutral, and the ground), but I was wondering if there is
>any reason NOT to do what I propose or whether there are any special
>precautions I might have overlooked.
Having done (and undone, soon thereafter) what you're suggesting, I can
think of a few potential reasons why it's NOT a good idea:
1) The existing 240V receptacle may not (probably doesn't) have a neutral.
2) According to code, a 120V appliance circuit should be breakered at 20A
maximum. The existing 240V dryer circuit is probably breakered at 30A or
more. Not good. Even if you choose to ignore this point....
3) The dryer circuit is wired with heavy gauge (8 or 10 ga?) wire, which
physically won't fit on the terminals of a 120V receptacle. So you'd have
to splice down to 12 ga wire, which is good for 20A, getting you back to
problem #2.
4) Electrical inspectors hate it when you get creative.
So, I think it will be whole lot less hassle to just run a new 120V
circuit for the gas dryer.
Good luck,
Kent
______________________________________________
Kent Fitzgerald kent...@cns.nyu.edu
Center for Neural Science, New York University
Mike Brown
In article <SAM.96Ma...@colossus.stdavids.picker.com>, s...@stdavids.picker.com (Sam Goldwasser) writes:
|> In article <4oci58$3...@clarknet.clark.net> gu...@clark.net (Harlan Messinger) writes:
|>
|> > need a 120V receptacle instead of the existing 240V. I'd like to leave
|> > the 240V circuit there for possible future use. I understand the
|> > general precautions involved in home wiring and the mechanics of
|> > running an extension from the 240V box to a new 120V box (one hot
|> > wire, the neutral, and the ground), but I was wondering if there is
|> > any reason NOT to do what I propose or whether there are any special
|> > precautions I might have overlooked.
|>
|> and ground/neutral. The separate hot and neutral wirss required for a
|> properly connected 120 V outlet are not available without running an
|> additional line from the service panel.
|>
|> If it has 4 wires, then extending one H and the N and G to a new outlet
|> should not be a problem.
|>
|> --- sam
|>
|> > Thanks in advance.
|>
I've been watching this thread waiting for someone to recognize
the shock hazard potential here, and Sam has done so quite nicely. Many
drier connections do not have a neutral connection, which is needed for
a proper 120-volt outlet. You might be tempted to cheat and use the
ground connection for that purpose, *BUT* you are at risk of a lethal
shock if the ground connection opens.
Don't try this at home, Kids! (at least, not at *my* home)
As Sam observes, no problem if the outlet is 4-wire.
The observations about breaker rating are also valid. Nothing past the
new outlet is rated for more than 15 amps, so could burn nicely without
tripping the breaker. I'll bet your homeowner's insurance
wouldn't pay off on a fire with this as a (potential) origin.
FWIW
regards
Mike
(not an electrician)
--
Mike Brown - Development Engineer Life Member - NRA & TSRA
Tandem Computers, Austin, TX Mensch-in-training
(fire)POWER TO THE PEOPLE!
Keep the Faith - Never Disarm - Write for your Rights - One Day At A Time
george
:>may be easier to hook up the new outlet with receptacle and wire
:>rated for 30amps.. Problems with this?
:
:There are if you do not change the *protection* to 15 amps. The new
:appliance has a plug that is rated for 15 amps and must plug into
:a receptacle rated for 15 amps (or one for 20 amps, in the US).
ok, a parallel question, my 15(or20?)amp 110 dryer outlet is keyed
so that the dryer can only be plugged into that outlet
but you could also plug any other 110 appliance there. That
is it would seem ok to plug a lamp in there, or put another
way the lamp with its little cord doesn't appear to need the
'protection' of say a 10 amp breaker. Right? So is it just certain
appliances that must be used only with a certian breaker
protection?
--
george
geo...@mech.seas.upenn.edu
Alan Noelle
george (je...@blue.seas.upenn.edu) wrote:
:
: ok, a parallel question, my 15(or20?)amp 110 dryer outlet is keyed
: so that the dryer can only be plugged into that outlet
: but you could also plug any other 110 appliance there. That
: is it would seem ok to plug a lamp in there, or put another
: way the lamp with its little cord doesn't appear to need the
: 'protection' of say a 10 amp breaker. Right? So is it just certain
: appliances that must be used only with a certian breaker
: protection?
In short...yes. Your dryer is probably a gas appliance if it is using a
using a standard 15 or 20A wall plug. The electricity is merely to
control the logic and lights and such within the unit.
A good rule of thumb is in the plug. All electrical outlet plugs SHOULD
not be able to be plugged into a wall outlet of lesser ampacity than the
unit requires. For instance, a 30A appliance should have a 30A plug
on it, and 30A plugs will not fit into a 20A outlet.
Of course, I've seen this rule both bent (literally) and blatantly
broken. So it's always good to check the appliance label. As an example,
I've seen a number of computer companies in my area take the "T" shaped prong
on a 20A plug, and bend it back with a pair of pliers to make it fit
into a standard 15A wall plug =)
Alan J Noelle, P.E.
##------------------------------------------------------------------------##
# "Around here we talk just like Lions, #
# but we sacrifice like lambs." Counting Crows #
##--dio...@west.net---------Sanctuary---------dionysus@akasha.punk.net--##
Dave Smith
je...@red.seas.upenn.edu (george) wrote:
>:That would be fine if one were doing away with the 240 volt outlet,
>:but the original poster wishes to keep the 240 volt outlet intact
>:for a possible future need.
>:
>:One way to accomplish this would be to add a small single fuse/breaker
>:box off one leg of the 240 volt/30 amp dryer outlet that feeds the
>:120 volt/15 amp outlet. This will provide the necessary protection for
>:the lower-rated outlet while keeping the higher-rated outlet intact for
>:future use.
>may be easier to hook up the new outlet with receptacle and wire
>rated for 30amps.. Problems with this?
That is a expensive way to do it. Just replace the dryer breaker
with a single15 amp breaker. By using a flat plaster ring, you can
change the receptacle on the dryer box to a normal receptacle. The
old breaker and receptacle can be kept and replaced if necessary in
the future.
Water Valley, Alberta, Canada
george
:In short...yes. Your dryer is probably a gas appliance if it is using a
:control the logic and lights and such within the unit.
yes gas dryer. Actually its a stackable washer/dryer, probably
the washer needs the current.
:A good rule of thumb is in the plug. All electrical outlet plugs SHOULD
:not be able to be plugged into a wall outlet of lesser ampacity than the
:unit requires. For instance, a 30A appliance should have a 30A plug
:on it, and 30A plugs will not fit into a 20A outlet.
right, the issue was plugging into an outlet with *greater*
"ampacity" than required. If there is no such beast as a 30A
outlet that accepts a standard plug, then that answers that question
though.
--
george
geo...@mech.seas.upenn.edu
Sam Goldwasser
> ok, a parallel question, my 15(or20?)amp 110 dryer outlet is keyed
> so that the dryer can only be plugged into that outlet
> but you could also plug any other 110 appliance there. That
> is it would seem ok to plug a lamp in there, or put another
> way the lamp with its little cord doesn't appear to need the
> 'protection' of say a 10 amp breaker. Right? So is it just certain
> appliances that must be used only with a certian breaker
> protection?
That sounds like a 20A outlet with a 20A plug. Thus, you could not plug
the dryer into a 15A outlet.
--- sam
.
Calvin Henry-Cotnam
Mike Brown (mbr...@mpd.tandem.com) said...
>
>I've been watching this thread waiting for someone to recognize
>the shock hazard potential here, and Sam has done so quite nicely. Many
>drier connections do not have a neutral connection, which is needed for
>a proper 120-volt outlet.
Why have a few people mentioned this?
Yes, it is a valid point, overall, but in the context of a dryer
outlet, there should be a proper neutral there. Many dryers need a
neutral connection because many have a motor and controls that operate
on 120 volts. It is the heating elements that need the 240 volts.
Are things that different in the USA?
Here in Canada, all dryers are sold with the same standard plug
and one can go to a home centre or electrical supplier and purchase
a "dryer outlet" that that standard plug fits into. These all have
two lines, a neutral, and a ground.
>You might be tempted to cheat and use the ground connection for that
>purpose, *BUT* you are at risk of a lethal shock if the ground
>connection opens.
Or possibly if it is funcitoning perfectly! Using the ground conductor
to carry current that the neutral is intended for means that the ground
of the outlet is not at ground. Since conductors are not "perfect" (ie:
no resistance), any current through the conductor will develop a
voltage drop. With the building's ground as a reference of zero volts,
the ground pin of the outlet could very well be several volts "away"
from ground when something is pulling current through the conductor.
This means that a chassis grounded to this "ground" has a potential
of a few volts and should you touch it and a well-grounded item (metal
plumbing for instance)....
Stewart Thompson
gu...@clark.net (Harlan Messinger) wrote:
>We're replacing our electric clothes dryer with a gas model, so we
>need a 120V receptacle instead of the existing 240V. I'd like to leave
>the 240V circuit there for possible future use. I understand the
>general precautions involved in home wiring and the mechanics of
>running an extension from the 240V box to a new 120V box (one hot
>wire, the neutral, and the ground), but I was wondering if there is
>any reason NOT to do what I propose or whether there are any special
>precautions I might have overlooked.
>
>
>
WARNING!!! THE VOLTAGE DISCUSSED HERE ARE HIGH ENOUGH TO BE
LETHAL OR CAUSE SERIOUS INJURY. ALL WORK MUST BE DONE WITH THE
CIRCUITS DE-ENERGIZED AND PROPERLY LOCKED OUT. REMOVE THE WIRES
FROM THE BREAKER IF NECESSARY. ALL LOCAL ELECTRICAL CODE RULES
MUST BE MET. I CAN NOT STRESS ENOUGH PROPER OVERCURRENT
PROTECTION AND PROPER BONDING.
Harlan:
In most areas dryer plugs use 10 Gauge copper wire and are
fed by a 2 pole 30 Ampere breaker. Standard duplex plugs are
only rated at 15 or 20 Amperes depending on the style and the
Electrical Code in the area. The box will probably accept a
face plate which can mount one or two duplex receptacles. You
have a couple of choices. You could marret off one of the hot
leads (red of black) and pigtail the remaining hot, the neutral
wire (white or gray), and the bond wire (green or bare copper
to the receptacle. Or you could use two duplex receptacle with
a common neutral and both hots. This would give you two
independant circuits. I don't know the code rules in your area,
but if you choose this option I would recommend a two pole
breaker or tieing the two breaker handles together with a bar.
Check with your local Electrical Inspector for guidance on this
point. Do not try to tie the #10 wire directly to the outlet
receptacle. Most are not designed to handle wire that large.
Pigtail a smaller size wire from the receptacle to the larger
wire using wire nuts (called marrets in my local). Check with
your local Inspector for the proper size.
VERY IMPORTANT! Do not leave the 30A breaker feeding your new
circuits. You MUST install the proper breaker, probably 15 or
20 Amperes. Check your local Electrical Code. Make sure that
the breaker will accept the larger wire before purchasing it.
I would check out all these options and have all the items in
place before you start anything.
I hope this helps.
WARNING!!! THE VOLTAGE DISCUSSED HERE ARE HIGH ENOUGH TO BE
LETHAL OR CAUSE SERIOUS INJURY. ALL WORK MUST BE DONE WITH THE
CIRCUITS DE-ENERGIZED AND PROPERLY LOCKED OUT. REMOVE THE WIRES
FROM THE BREAKER IF NECESSARY. ALL LOCAL ELECTRICAL CODE RULES
MUST BE MET. I CAN NOT STRESS ENOUGH PROPER OVERCURRENT
PROTECTION AND PROPER BONDING. THE SAFETY OF PEOPLE AND
PROPERTY MUST BE THE PRIME CONSIDERATION, OBSERVE SAFE WORK
PROCEDURES AT ALL TIMES!
REMEMBER. ELECTRICAL CODE RULES ARE THERE FOR A REASON. SOME
PEOPLE HAD TO PAY WITH THERE LIVES IN SOME CASES. OBSERVE THEM.
ENOUGH SAID.
Good Luck!
Stu.......
kent...@cns.nyu.edu
>ok, a parallel question, my 15(or20?)amp 110 dryer outlet is keyed
>so that the dryer can only be plugged into that outlet
>but you could also plug any other 110 appliance there.
Sounds like you're talking about a 120V, 20A receptacle. One of the slots
is T-shaped, so it will accept either a regular 15A plug (parallel blades)
or a 20A plug like the one on your dryer (perpendicular blades).
>So is it just certain
>appliances that must be used only with a certian breaker
>protection?
It's considered OK to run any 120V appliance on either a 15A or 20A circuit.
Stewart Thompson
Paul F. Blomberg, P.E.
Dwa...@mddc.com wrote:
>In article <4oci58$3...@clarknet.clark.net>, gu...@clark.net (Harlan
>Messinger) wrote:
>> We're replacing our electric clothes dryer with a gas model, so we
>> need a 120V receptacle instead of the existing 240V. I'd like to leave
>> the 240V circuit there for possible future use. I understand the
>> general precautions involved in home wiring and the mechanics of
>> running an extension from the 240V box to a new 120V box (one hot
>> wire, the neutral, and the ground), but I was wondering if there is
>> any reason NOT to do what I propose or whether there are any special
>> precautions I might have overlooked.
>>
>> Thanks in advance.
I assume the washer is next to the dryer. Just plug the gas dryer
into the same outlet as the washer. IT HAS WORKED for over 40 years
that way in my home and many others. I've never overloaded the
circuit even when running both washer and dryer.
Leave the 220V alone!
Good luck,
Paul.
CAll me Chris
In article <4oinmu$k...@acme.sb.west.net>, dion...@west.net (Alan Noelle) wrote:
> george (je...@blue.seas.upenn.edu) wrote:
> :
> : ok, a parallel question, my 15(or20?)amp 110 dryer outlet is keyed
> : so that the dryer can only be plugged into that outlet
> : but you could also plug any other 110 appliance there. That
> : is it would seem ok to plug a lamp in there, or put another
> : way the lamp with its little cord doesn't appear to need the
> : 'protection' of say a 10 amp breaker. Right? So is it just certain
> : appliances that must be used only with a certian breaker
> : protection?
>
> In short...yes. Your dryer is probably a gas appliance if it is using a
> using a standard 15 or 20A wall plug. The electricity is merely to
> control the logic and lights and such within the unit.
Err...I think that there is probably a motor in there somewhere to turn
the inside. This would probably require at least a 15-20 amp
breaker......
--
Question authority? Only the highest authorities are worth questioning. All others are just interpretations.
Sam Goldwasser
> Mike Brown (mbr...@mpd.tandem.com) said...
> >
> >I've been watching this thread waiting for someone to recognize
> >the shock hazard potential here, and Sam has done so quite nicely. Many
> >drier connections do not have a neutral connection, which is needed for
> >a proper 120-volt outlet.
> Why have a few people mentioned this?
> Yes, it is a valid point, overall, but in the context of a dryer
> outlet, there should be a proper neutral there. Many dryers need a
> neutral connection because many have a motor and controls that operate
> on 120 volts. It is the heating elements that need the 240 volts.
> Are things that different in the USA?
Apparently there are exceptions to the normal NEC rules about separate
Neutral and Ground conductors - dryers and ranges fall into this category.
I would be curious to hear justification other than cost for not having
separate wires. Or, has this deficiency been corrected in the newer
NEC rules? Is this permitted in new installations?
--- sam
H.D.Moss
In article <SAM.96Ju...@colossus.stdavids.picker.com>,
s...@stdavids.picker.com says...
Well I feel it's time for my $0.02. Yes, Sam, the NEC has for years had
an exception for the grounding of ranges and dryers. Article 250-60
states that the neutral can be used as ground. This has been changed in
the 1997 NEC to require 4-wire supply for new construction. As for an
explanation, I'm not sure but perhaps it's because until sometime in
the 60's, (not sure of when exactly), grounding of receptacles in
residences was not required for general use receptacles. I have seen
old knob and tube wired circuits where even Neutral-Line were not kept
track of (i.e., switched neutrals to light fixtures). Perhaps when
electric appliances that required more than a 15-20 amp circuit were
developed the neutral was more likely to be looked at as a reliable
ground than we do today. At any rate, I feel that scabbing a 20 amp
circuit off of this circuit is bad practice unless:
1: There is a 4 wire cable to the box.
2: The 30 amp receptacle was removed.
3: A 20 amp circuit breaker was installed to feed one line
4: The box (if metal) and the receptacle are bonded to the ground
conductor
If a person wanted to restore the 30 amp circuit, the original breaker
and receptacle could be re-installed. Of course the best way is to
install a dedicated 20 amp circuit with a 20 amp receptacle,and leave
the 30 amp circuit alone for future use.
mho as an electrician.
H.D.
safe male
gu...@clark.net (Harlan Messinger) wrote:
>We're replacing our electric clothes dryer with a gas model, so we
>need a 120V receptacle instead of the existing 240V. I'd like to leave
>the 240V circuit there for possible future use. I understand the
>general precautions involved in home wiring and the mechanics of
>running an extension from the 240V box to a new 120V box (one hot
>wire, the neutral, and the ground), but I was wondering if there is
>any reason NOT to do what I propose or whether there are any special
>precautions I might have overlooked.
>Thanks in advance.
for one the dryer most use a 30 amp bracker
the 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
by law
Dean Philips
safe male wrote:
>
> gu...@clark.net (Harlan Messinger) wrote:
>
> >We're replacing our electric clothes dryer with a gas model, so we
> >need a 120V receptacle instead of the existing 240V. I'd like to leave
> >the 240V circuit there for possible future use. I understand the
> >general precautions involved in home wiring and the mechanics of
> >running an extension from the 240V box to a new 120V box (one hot
> >wire, the neutral, and the ground), but I was wondering if there is
> >any reason NOT to do what I propose or whether there are any special
> >precautions I might have overlooked.
>
> >Thanks in advance.
>
> The 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
> by law
>
The code splits the ground and neutral wires at the main breaker
pannel (except for a few special cases) and one wire is not generaly
used for both. I suppose you could rewire at the breaker pannel,
using both legs of the old drier wire for each side of 120 volts and
the ground for ground, and using an approporiate sized breaker, i.e.
20 ampere. But, you must make sure the outlet you install has
terminals rated for the larger wire size you intend on attaching
(or use wire nuts to install pigtails).
--
===========================================================
Dean E. Philips, P.E.
phil...@postoffice.worldnet.att.net
Tim Fischer
> gu...@clark.net (Harlan Messinger) wrote:
>
> >We're replacing our electric clothes dryer with a gas model, so we
> >need a 120V receptacle instead of the existing 240V. I'd like to leave
> >the 240V circuit there for possible future use. I understand the
> >general precautions involved in home wiring and the mechanics of
> >running an extension from the 240V box to a new 120V box (one hot
> >wire, the neutral, and the ground), but I was wondering if there is
> >any reason NOT to do what I propose or whether there are any special
> >precautions I might have overlooked.
>
> >Thanks in advance.
>
>
> for one the dryer most use a 30 amp bracker
> the 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
> by law
>
Please -- I was interested in this reply, but have no idea what's being
said here. Could you please restate more clearly?
Thanks!
-Tim
--
---------------------------------------
Tim Fischer
tfis...@codamusic.com
Richard M.
Dean Philips wrote:
>
> safe male wrote:
> >
> > gu...@clark.net (Harlan Messinger) wrote:
> >
> > >We're replacing our electric clothes dryer with a gas model, so we
> > >need a 120V receptacle instead of the existing 240V. I'd like to leave
> > >the 240V circuit there for possible future use. I understand the
> > >general precautions involved in home wiring and the mechanics of
> > >running an extension from the 240V box to a new 120V box (one hot
> > >wire, the neutral, and the ground), but I was wondering if there is
> > >any reason NOT to do what I propose or whether there are any special
> > >precautions I might have overlooked.
> >
> > >Thanks in advance.
> >
> > The 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
> > by law
????
By law? Code only requires that the receptacle be rated to handle the
current supply. If he has a 30 AMP breaker and 10AWG wire, he is fine
with a 30 AMP receptacle.
I recommend that you take the existing 220v wiring and use it to wire a
proper 120v outlet. That is, use one wire for single phase hot, one for
neutral, and the other for ground (previously the other hot line). This
allows for the required split on ground and neutral. You can then just
remove the 220v receptacle and pigtail in the 120v receptacle using the
proper wire size for the breaker you chose. (remove the old 220v
breaker and install a 20amp, is my suggestion)
This way, you are within code and can *easily* convert back. Don't most
dryers sit next to washers and isn't there alrady a 120V service??
Michel Gagnon
Dans ląarticle (in article) <539nde$1...@news.fwi.com>,
safe...@mail.fwi.com (safe male) a dit (said) :
>gu...@clark.net (Harlan Messinger) wrote:
>
>>We're replacing our electric clothes dryer with a gas model, so we
>>need a 120V receptacle instead of the existing 240V. I'd like to leave
>>the 240V circuit there for possible future use. I understand the
>>general precautions involved in home wiring and the mechanics of
>>running an extension from the 240V box to a new 120V box (one hot
>>wire, the neutral, and the ground), but I was wondering if there is
>>any reason NOT to do what I propose or whether there are any special
>>precautions I might have overlooked.
>
>>Thanks in advance.
>
>
Legally speaking, you cannot "convert" a live red conductor to a neutral
"identified" (i.e. white) neutral one.
This means that the existing outlet is powered by a 10/3 cable, that is, a
cable with three conductors (red, black and white) plus ground, you can do
it legally. Otherwise, I am aware that some licensed electricians will
convert the red conductor into a neutral one, but it is not legal practice
and should be avoided.
What should be done ?
Turn off the mains and open the panel. Disconnect the existing red wire
from the 30-A double-breaker and cap it with a small marrette. Make sure
the white conductor is attached to the neutral bus of the panel.
Disconnect the existing black wire from the 30-A double-breaker. Replace
this double-breaker with two 15-A or 20-A breakers (check with your city
inspector or the nameplate of the gas dryer to see if it requires a 15-A
or 20-A feed in U.S.. I know it calls for 15-A in Canada, but it may
differ in U.S.. Connect the black wire to one of these new breakers. Leave
the other unused (to cover the hole) for future use.
In the receptacle box, disconnect the existing outlet; cap the red wire
and pigtail the black, white and ground conductors with #12 conductors,
and connect a proper 15-A or 20-A 120-V receptacle to these wires.
Adequate covers for standard outlets in 4-in boxes exist for that purpose.
If, however, you only have a 2-conductor (plus ground) feed to the 240-V
outlet, your only legal option would be to rewire. You could leave the
existing outlet in place (for future use), and simply replace the breakers
as above (or add a new circuit if there is room in the panel). That way,
if you ever need to install an electric dryer, you wonąt have to rewire
again -- a plus if you sell your house.
--
Michel Gagnon
mga...@total.net
Montréal (Québec, Canada)
J.Joe Jones
Dean Philips <phil...@postoffice.worldnet.att.net> wrote:
>safe male wrote:
>>
>> gu...@clark.net (Harlan Messinger) wrote:
>>
>> >We're replacing our electric clothes dryer with a gas model, so we
>> >need a 120V receptacle instead of the existing 240V. I'd like to leave
>> >the 240V circuit there for possible future use. I understand the
>> >general precautions involved in home wiring and the mechanics of
>> >running an extension from the 240V box to a new 120V box (one hot
>> >wire, the neutral, and the ground), but I was wondering if there is
>> >any reason NOT to do what I propose or whether there are any special
>> >precautions I might have overlooked.
>>
>> >Thanks in advance.
>>
>> for one the dryer most use a 30 amp braker.
>> The 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
>> by law
>>
>The code splits the ground and neutral wires at the main breaker
>pannel (except for a few special cases) and one wire is not generaly
>used for both. I suppose you could rewire at the breaker pannel,
>using both legs of the old drier wire for each side of 120 volts and
>the ground for ground, and using an approporiate sized breaker, i.e.
>20 ampere. But, you must make sure the outlet you install has
>terminals rated for the larger wire size you intend on attaching
>(or use wire nuts to install pigtails).
I believe an examination of most, if not all, residential services
that are being use as "service equipment" will reveal that there is
no "splitting" of the equipment grounding conductors, (green insulated
or bare) and grounded conductors (white) into separate buss bars. If
separate bars are encountered, at the service equipment, a strap,
screw, or some other mechanical link will be found to connect them.
Separation of the respective bars does occur at sub-panels within the
same structure.
J.Joe Jones
altavoz
".. some other mechanical link will be found to connect them."
NO, NOT , NO WAY ! They must be connected only at the service entrance
( fuse box/breaker panel).
115 vac has 1 breaker, 230 vac has 2 breakers ( for safety, you must
brk both sides cause they are both hot to nuetral). A house in the
US has(230vac) red( hot) black ( hot) and nuetral( white) and ground
( bare)
NEVER HOOK THE GROUND TO NUETRAL ANYWHERE OTHER THAN THE BREAKER BOX.
NO amps should ever flow on the ground ( except as a fault .."GFI")
Disconnect the red at the brkr box and insulate, move the black over
to a smaller , legal ( 115 vac) breaker , you now have a standard 115
at the proper color code ( black=hot , white=nuetral ground the bare)
BTW O'Scopes wont work if you use more than 2 wires...
______End of text from altavoz___________
J.Joe Jones
altavoz <alt...@worldnet.att.net> wrote:
Despite what Altavoz said, the connection I referred to in my earlier
post, and its location, are correct per the NEC. The connection
between the "grounded" and "grounding" conductors occurs at the
SERVICE EQUIPMENT. Twice in my first post I specifically used the
term _service equipment_ to define the location I was referring to.
The terms. _SERVICE EQUIPMENT_ and _SERVICE_ are both defined in
Art. 100 of the NEC and could help in understanding the requirements
for a _MAIN BONDING JUMPER_ , which is the connection between the
"grounded" and "grounding" conductors being discussed.
One point I do wish to expand upon is the "screw, strap. or other
mechanical link" that I referred to as the method used to connect the
two types of conductors. It would be more accurate to refer to this
connection as an _electrical_ connection achieved mechanically with a
screw, strap, etc.
(snipped) Explanation of circuit breakers.
>NEVER HOOK THE GROUND TO NUETRAL ANYWHERE OTHER THAN THE BREAKER BOX.
I do not wish to "confuse" the issue at hand, but _never_ is not
quite accurate. There are specific instances where the "grounded" and
"grounding" conductors may be joined together other than at the
Service equipment, but the permissible locations are clearly
identified by the NEC.
>NO amps should ever flow on the ground ( except as a fault .."GFI")
>Disconnect the red at the brkr box and insulate, move the black over
>to a smaller , legal ( 115 vac) breaker , you now have a standard 115
>at the proper color code ( black=hot , white=nuetral ground the bare
The _choice_ of colors, red or black, to be attached to the single
pole circuit breaker is at the disgression of the user, the NEC does
not take a position, that I am aware of.
altavoz
altavoz says:
>".. some other mechanical link will be found to connect them."
> >NO, NOT , NO WAY ! They must be connected only at the service entrance
> >( fuse box/breaker panel).
J JOE JONES :
> Despite what Altavoz said, the connection I referred to in my earlier
> post, and its location, are correct per the NEC. The connection
> between the "grounded" and "grounding" conductors occurs at the
> SERVICE EQUIPMENT.
altavoz :
nobody except those who are bookworms and never bend EMT
use "SERVICE EQUIP"
J.JONES:
Twice in my first post I specifically used the
> term _service equipment_ to define the location I was referring to.
> The terms. _SERVICE EQUIPMENT_ and _SERVICE_ are both defined in
> Art. 100 of the NEC and could help in understanding the requirements
> for a _MAIN BONDING JUMPER_ , which is the connection between the
> "grounded" and "grounding" conductors being discussed......snip
>
> One point I do wish to expand upon is the "screw, strap. or other
> mechanical link" that I referred to as the method used to connect the
> two types of conductors. It would be more accurate to refer to this
> connection as an _electrical_ connection achieved mechanically with a
> screw, strap, etc.
altavoz :
this is a perfect example of one who reads and does not DO.
J.jones has the NEC memorized but has never worked with those
who bend the conduit !! They all call it SERVICE ENTRANCE and
so does HOME DEPOT and others !
.....NEVER HOOK THE GROUND TO NUETRAL ANYWHERE OTHER THAN THE BREAKER BOX.
J.Jones:
> I do not wish to "confuse" the issue at hand, but _never_ is not
> quite accurate. There are specific instances where the "grounded" and
> "grounding" conductors may be joined together other than at the
> Service equipment, but the permissible locations are clearly
> identified by the NEC.
altavoz:
You notice J.JONES cant be specific here. We all want to know where
it's permissable to short the nuetral to the bare ? Lets have it J.JONES
> >NO amps should ever flow on the ground ( except as a fault .."GFI")
> >Disconnect the red at the brkr box and insulate, move the black over
> >to a smaller , legal ( 115 vac) breaker , you now have a standard 115
> >at the proper color code ( black=hot , white=nuetral ground the bare
J.JONES:
> The _choice_ of colors, red or black, to be attached to the single
> pole circuit breaker is at the disgression of the user, the NEC does
> not take a position, that I am aware of.
You are full of it !! Even if NEC didnt , your common sense tells
you that it would confuse other electricians to see a red carrying
the same phase as a black !!!!
QUIT YOUR ARGUING , YOU LOST !! YOU CANT EXPLAIN SIMPLY THINGS
IN SIMPLE TERMS. Read MICHEL GAGNON's reply it seems to be the
best so far . He unlike you probably works for a living.
_____End of text from altavoz___________
J.Joe Jones
altavoz <alt...@worldnet.att.net> wrote:
>altavoz says:
>>".. some other mechanical link will be found to connect them."
>> >NO, NOT , NO WAY ! They must be connected only at the service entrance
>> >( fuse box/breaker panel).
>J JOE JONES :
>> Despite what Altavoz said, the connection I referred to in my earlier
>> post, and its location, are correct per the NEC. The connection
>> between the "grounded" and "grounding" conductors occurs at the
>> SERVICE EQUIPMENT.
>altavoz :
>nobody except those who are bookworms and never bend EMT
>use "SERVICE EQUIP"
>J.JONES:
> Twice in my first post I specifically used the
>> term _service equipment_ to define the location I was referring to.
>> The terms. _SERVICE EQUIPMENT_ and _SERVICE_ are both defined in
>> Art. 100 of the NEC and could help in understanding the requirements
>> for a _MAIN BONDING JUMPER_ , which is the connection between the
>> "grounded" and "grounding" conductors being discussed......snip
>>
>> One point I do wish to expand upon is the "screw, strap. or other
>> mechanical link" that I referred to as the method used to connect the
>> two types of conductors. It would be more accurate to refer to this
>> connection as an _electrical_ connection achieved mechanically with a
>> screw, strap, etc.
>altavoz :
>this is a perfect example of one who reads and does not DO.
>J.jones has the NEC memorized but has never worked with those
>who bend the conduit !! They all call it SERVICE ENTRANCE and
>so does HOME DEPOT and others !
>.....NEVER HOOK THE GROUND TO NUETRAL ANYWHERE OTHER THAN THE BREAKER BOX.
>J.Jones:
>> I do not wish to "confuse" the issue at hand, but _never_ is not
>> quite accurate. There are specific instances where the "grounded" and
>> "grounding" conductors may be joined together other than at the
>> Service equipment, but the permissible locations are clearly
>> identified by the NEC.
>altavoz:
>You notice J.JONES cant be specific here. We all want to know where
>it's permissable to short the nuetral to the bare ? Lets have it J.JONES
This is the only point I will respond to, you might try reading
Article 250-24. With your electrical background, I 'm surprised you
missed it.
> >NO amps should ever flow on the ground ( except as a fault .."GFI")
>> >Disconnect the red at the brkr box and insulate, move the black over
>> >to a smaller , legal ( 115 vac) breaker , you now have a standard 115
>> >at the proper color code ( black=hot , white=nuetral ground the bare
>J.JONES:
>> The _choice_ of colors, red or black, to be attached to the single
>> pole circuit breaker is at the disgression of the user, the NEC does
>> not take a position, that I am aware of.
>You are full of it !! Even if NEC didnt , your common sense tells
>you that it would confuse other electricians to see a red carrying
>the same phase as a black !!!!
>QUIT YOUR ARGUING , YOU LOST !! YOU CANT EXPLAIN SIMPLY THINGS
>IN SIMPLE TERMS. Read MICHEL GAGNON's reply it seems to be the
>best so far . He unlike you probably works for a living.
>_____End of text from altavoz___________
I refuse to engage in a battle of wits with an unarmed man.
Sign me,
The NEC bookworm,
J.Joe Jones
State license 395271 Ca.
Richard M.
Tim Fischer wrote:
> > for one the dryer most use a 30 amp bracker
> > the 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
> > by law
> >
>
> said here. Could you please restate more clearly?
>
> Thanks!
Tim, there were many (myself included) who gave a detailed response to
this question. Read back in the thread. This particular reply is not
only unclear, but wrong from what little info I see.
"Law"? I think he may mean "code" and even then his statement makes
little or no sense.
Richard M.
J.Joe Jones wrote:
>
> I refuse to engage in a battle of wits with an unarmed man.
>
> Sign me,
> The NEC bookworm,
>
> J.Joe Jones
> State license 395271 Ca.
Perfect, J.
I like your style.
BTW, did you get that nonsense about using two wires on an O'scope?
Seems the guy has decided to compromise safety inlieu of proper bench
power... if he knows what he is yammering about at all.
--
"Nobody ever went broke underestimating
the intelligence of the American public."
Richard G. Mainar Digi...@serv.net
Calvin Henry-Cotnam
J.Joe Jones (jjj...@primenet.com) said...
>
>altavoz <alt...@worldnet.att.net> wrote:
>
>>NEVER HOOK THE GROUND TO NUETRAL ANYWHERE OTHER THAN THE BREAKER BOX.
>
>I do not wish to "confuse" the issue at hand, but _never_ is not
>quite accurate. There are specific instances where the "grounded" and
>"grounding" conductors may be joined together other than at the
>Service equipment, but the permissible locations are clearly
>identified by the NEC.
In an attempt to make things clearer, I would add that the above
capatalized line should have "BREAKER BOX" replaced with "SERVICE
ENTRANCE".
I have edited out Mr. Jones' description of service entrance, but
suffice it to say that a breaker box, breaker pannel, or distribution
pannel (choose your preferred term) is not necessarily the same as
the service entrance. Though many homes now use what is more correctly
named a "combination pannel" that serves as the entrance and the
distribution centre (and therefore has the grounded [neutral] and the
grounding [ground] conductors connected), this should not be assumed
to be the situation in every case.
Some installations have a separate disconnect (ie; main breaker box)
that serves as the entrance. In fact, if you have an indoor power
meter (rare these days), a separate disconnect is necessary as the
meter is located *after* it but before the load centre.
Besides all this, you may find that a particular branch circuit runs
back to a sub-panel and in such cases, the grounded and grounding
conductors are not connected together at such a "breaker box".
--
Calvin Henry-Cotnam, CATE | "This is just temporary.
Ryerson Polytechnic University | Unless it works."
Toronto, Ontario, Canada | - Red Green
Joseph Kral
In article <53ehg1$p...@nnrp1.news.primenet.com>,
J.Joe Jones <jjj...@primenet.com> wrote:
>
>I do not wish to "confuse" the issue at hand, but _never_ is not
>quite accurate. There are specific instances where the "grounded" and
>"grounding" conductors may be joined together other than at the
>Service equipment, but the permissible locations are clearly
>identified by the NEC.
>
Those exceptions that you refer to have been eliminated in the latest rev.
of the code. "Never" is now the appropriate word for that situation.
hobdbcgb
Haven't either of you ever wired a kitchen outlet string?
Remember pulling the 4-wire (red ph1, bl ph2, wht neu, and bare grnd.)?
Upper outlet gets 120 plus and lower gets 120 minus? (I would have called
them phases, but would you both have bit me for listing more than one
phase in a residential single phase system.) A lot of dwellings have them.
(Connected off their NEC approved aluminum service leads, which are no
longer permitted in most jurisdictions up north.)
Making the poor poster go through great hoops for semantics. Shame on
you, and one of you knowing about the wierd California codes, too.
Different areas have different names, you know. For example: "Service
equipment" around here is the box with stuff you get off the shelf in the
store to use at the service entrance. "Service entrance" around here is
the place in the building where the power comes in, where the initial
power distribution occurs, and where the neutral and the protection ground
are referenced to the earth, although the power company guys always seem
to be talking about their wires and not mine.
My code-approved service (checked by the inspector, master electrician,
and me) which has approved service equipment and which sits at my approved
service entrance, has a long shiny buss full of bare wires for earth
ground and protection grounds and is connected to the box itself, and it
has a separate long shiny neutral buss full of white wires which is
connected to the earth buss by wire.
The kitchen run is the same lead as a dryer in many states- red,
black, neutral, and earth ('cause some controllers run on 120). Some
jurisdictions even let you, and some require you, to earth ground
directly, and some prohibit you from earth grounding such equipment back
to the mains because you might trust that rusty connection on the
vibrating equipment.
It all makes as much sense as a couple of other things in the NEC,
which is why we have JIC, and why OSHA doesn't accept NEC and has it's
own code. That's why we have UL, engineers, and safety people. The NEC has
its place, but it's not next to the Bible/Koran/etc.
If you believe that both sides of 240 are broken as standard practice,
don't run your hands inside air conditioners and a lot of other 240
appliances - they only break one lead -legally. Knocked on butt.
If you believe the NEC cares about voltage drop other than for fire
protection purposes, don't run any lines over 60 feet. Groaning motors.
If you think those NEC charts are some universal standard, check that #8
wire feeding your 200 amp service.
If you think the NEC air ratio is a standard, look in a motor connection
box sometime- different world.
And if you think the California Code or the Michigan Code or the Jersey
Code is the last word, you really need to get out and take a vacation.
Spend a couple weeks in New York with some of the union boys - an
experience every contractor and engineer should have.
A bit of advice on quoting the NEC in electrical engineering newsgroups
rather than in electrical compliance newsgroups. It is the National
Electrical Code, by the National Fire Protection Assoc., which should tell
you something of its purpose. It used to carry a disclaimer in the front
advising that it was not to be considered a substitute for proper
engineering, but that was removed because of.. let's see.. what was that
reason?
Call it a minimum standard. Call it a fire code. Call it a guide. But
I don't think anyone who has used it over the years would call it worth
arguing over.
Stay safe.
altavoz
________________________________altavoz says below_______________________-
Eventually , you'll find many engineers posting here to back
me up on the fact that the nuetral ( at the service entrance)
is hooked to the 4 inch lead ( ground ) on a 10:1 scope probe
and the probe is hooked to the case of the scope !! We have a
loop and it's hundreds of feet long .
BTW if ur into scope probes , when i was 4 years into endentured
slavery in electronics ( 1978), i challenged the TECTRONICS rep
that his P6006 , 1 meter actually had a higher BW than the more
expensive probe cause it has 7.5 pf vs 11.5 pf? He later agreed
and still later they got smart and made the 500 and 5000 ohm 10:1
probes which load even less than the 10 megohm version.
For novices reading this , a 10 meg scope probe is worse than
a 5000 ohm scope probe as it loads the circuit more than 5000.
John Porter
Richard M. (digi...@serv.net) wrote:
I think he's trying to say that the 240V dryer circuit would be on
a 30 amp breaker, but the 110 volt receptacle must be on a 20 amp
or lower breaker. Maybe that was addressed in the other posts; they're
gone from my news server so I can't check. I assume they also addressed
the need for separate neutral and ground conductors for the 110 volt
receptacle, versus what is probably a 3-wire dryer circuit as allowed
by the pre-96 code. It's not unheard of for 3-wire range circuits to
be fed by service entrance cable which has no 4th grounding conductor,
but this seems less likely for a dryer circuit.
--
John Porter
jpo...@bu.edu
Richard M.
John Porter wrote:
> I think he's trying to say that the 240V dryer circuit would be on
> a 30 amp breaker, but the 110 volt receptacle must be on a 20 amp
> or lower breaker.
> jpo...@bu.edu
John, are you telling me that no 110v receptacle can be 30amp?
Doug & Rose Miller
jpo...@bu.edu (John Porter) wrote:
+Richard M. (digi...@serv.net) wrote:
+: Tim Fischer wrote:
+: > > for one the dryer most use a 30 amp bracker
+: > > the 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
+: > > by law
+: > >
+: >
+: > Please -- I was interested in this reply, but have no idea what's being
+: > said here. Could you please restate more clearly?
+: >
+: > Thanks!
+
+: Tim, there were many (myself included) who gave a detailed response to
+: this question. Read back in the thread. This particular reply is not
+: only unclear, but wrong from what little info I see.
+: "Law"? I think he may mean "code" and even then his statement makes
+: little or no sense.
+
+I think he's trying to say that the 240V dryer circuit would be on
+a 30 amp breaker, but the 110 volt receptacle must be on a 20 amp
+or lower breaker. Maybe that was addressed in the other posts; they're
+gone from my news server so I can't check. I assume they also addressed
+the need for separate neutral and ground conductors for the 110 volt
+receptacle, versus what is probably a 3-wire dryer circuit as allowed
+by the pre-96 code. It's not unheard of for 3-wire range circuits to
+be fed by service entrance cable which has no 4th grounding conductor,
+but this seems less likely for a dryer circuit.
+
+--
+John Porter
+jpo...@bu.edu
For what it's worth, 3-wire 240V circuits using NM ("Romex") cable have
been prohibited by code since 1987 (or possibly earlier):
"In addition to the insulated conductors, [nonmetallic-sheathed] cable
shall be permitted to have an insulated or bare conductor for equipment
grounding purposes only." (1993 NEC, Art. 336-25) In other words, in NM
cable, the bare wire may not be used as the neutral. The 1990 and 1987
codes contain the same or similar language.
Also:
"Receptacles...having grounding contacts shall have those contacts
effectively grounded." (1993 NEC, Art. 210-7b)
Taken together, these would require that a 240V circuit supplying any
grounded receptacle, if wired with NM, *must* be wired with 3-conductor
NM with ground.
J. Zeigler
Richard M. wrote:
>
> John Porter wrote:
>
> > I think he's trying to say that the 240V dryer circuit would be on
> > John Porter
> > jpo...@bu.edu
>
> John, are you telling me that no 110v receptacle can be 30amp?
>
> --
> "Nobody ever went broke underestimating
> the intelligence of the American public."
>
> Richard G. Mainar Digi...@serv.net
Read it again, John Porter isn't telling you that. He's telling you that
he thinks thats what Tim said!
altavoz
> For novices reading this , a 10 meg scope probe is worse than
> a 5000 ohm scope probe as it loads the circuit more than 5000.
I could have done much better ! Sorry about that .
Many dont have the $$ for an active ( FET probe ) so we
try to fudge at very high frequencies with cheap 10 meg ohm,
10:1 probes ( called 10:1 cause they ten to one away when we
need them).
The scope looks like a 1 megohm parallel to 20 pf and the probe
looks like 9 meg ohm parallel to 7.5 pf but the coax has
capacitance and this is in parallel and added to the scope
so looking into the probe you see 9 meg//7.5 pf then 1 meg
parallel 67 pf. Most of the current is flowing into the caps
not the 9 meg or the scopes 1 meg at higher frequencies.
Some might say terminate the coax and you get rid of the
capacitance but terminating would mean paralleling the scopes
1 meg with a small resistor , and that dont work. ( thats why
they invented 500 ohm probe , so they could terminate the coax
in 50 ohms and yet get as high Z as a 10 megohm 10:1 !!
.....50 ohm coax with scope term' in 50 ohm and a 450 ohm resistor
at the probe tip means 500 Z , which is much better than the
10 meg probe cause it looks like 212 ohms at 100 mhz !! Tricky ?
the scope input is degraded from 1 meg to 50 ohms and it loads
the circuit less !
If you only have a 10 meg or 100 meg and u cant do the 500 ohm
probe and your circuit appears not to work, use a 10:1 with
< 8 p.f.( 1 meter cable) at the tip or even a 100:1 with 1 p.f. .
We're trying to raise the Z impedance by raising the Xc
( the 10 or 100 meg probe resistor is meaningless at these
frequencies)
________End of text from altavoz___________
--
John Phillips
On Mon, 07 Oct 1996 04:47:08 GMT, safe...@mail.fwi.com (safe male)
wrote:
The circuit breaker should be sized for the conductor not for the
load. Therefore, if you want to be perfectly correct, use the same
size conductors for the extension
>gu...@clark.net (Harlan Messinger) wrote:
>
>>We're replacing our electric clothes dryer with a gas model, so we
>>need a 120V receptacle instead of the existing 240V. I'd like to leave
>>the 240V circuit there for possible future use. I understand the
>>general precautions involved in home wiring and the mechanics of
>>running an extension from the 240V box to a new 120V box (one hot
>>wire, the neutral, and the ground), but I was wondering if there is
>>any reason NOT to do what I propose or whether there are any special
>>precautions I might have overlooked.
>
>>Thanks in advance.
>
>
>for one the dryer most use a 30 amp bracker
>the 110 volt outlet most not be on 20 amp it want a 15-20 amp 20
>by law
>
>
>
Regards,
John Phillips
NYPA
Buffalo-Niagara Falls
My comments express only
my personal opinions
Tim Fischer
Nope, read it again. I was quoting someone else (I believe it was someone
with the handle of 'safe male' but it's no longer on my server), and
asking for a clarification of what was being said, since it made
absolutely no sense.
Someone conveniently deleted my reference to that post when they quoted
me, but you'll notice that the extra set of '>'s are still there.
Not that I really care, but just thought I'd point that out...
J. Zeigler
>
> Nope, read it again. I was quoting someone else (I believe it was someone
> with the handle of 'safe male' but it's no longer on my server), and
> asking for a clarification of what was being said, since it made
> absolutely no sense.
>
> Someone conveniently deleted my reference to that post when they quoted
> me, but you'll notice that the extra set of '>'s are still there.
>
> Not that I really care, but just thought I'd point that out...
>
> -Tim
I stand corrected, I was able to trace the post only as far back as
jporter when he responded to a post by Richar M. and you are right, the
'>'s are still there.
Calvin Henry-Cotnam
hobdbcgb (hobd...@usinternet.com) said...
>
> Haven't either of you ever wired a kitchen outlet string?
>Remember pulling the 4-wire (red ph1, bl ph2, wht neu, and bare grnd.)?
>Upper outlet gets 120 plus and lower gets 120 minus?
This is the requirement under the Canadian Electrical Code. It is my
understanding that the NEC in the US is different.
>(I would have called them phases, but would you both have bit me for
>listing more than one phase in a residential single phase system.)
True. A more appropriate term for the two hot busses is "legs". You
connect the two different hots to different "legs" in the panel. This
term is more generic in that it applies to the two hots in a single
phase residential system (they are actually 180 degrees out-of-phase, but
this is mathematically considered the same phase), as well as panels
where more than one phase actually exists (commercial three-phase
installations and multi-family residential installations where the two
hots are actually two of three phases of a three-phase system -- my own
home in a high-rise condo is of this type).
Richard M.
Calvin Henry-Cotnam wrote:
> True. A more appropriate term for the two hot busses is "legs". You
> connect the two different hots to different "legs" in the panel. This
> term is more generic in that it applies to the two hots in a single
> phase residential system (they are actually 180 degrees out-of-phase, but
> this is mathematically considered the same phase), as well as panels
> where more than one phase actually exists (commercial three-phase
> installations and multi-family residential installations where the two
> hots are actually two of three phases of a three-phase system -- my own
However, phase-tophase voltage in three phase and single (biphase) are
very different. I'm not sure that all 240v devices will operate
properly at 3ph leg-to-leg voltage.
Steve Schlink
"Richard M." <digi...@serv.net> wrote:
>John Porter wrote:
>
>> I think he's trying to say that the 240V dryer circuit would be on
>> a 30 amp breaker, but the 110 volt receptacle must be on a 20 amp
>> or lower breaker.
>> John Porter
>> jpo...@bu.edu
>John, are you telling me that no 110v receptacle can be 30amp?
No 115v recp. that you are going to plug a gas dryer into !
Calvin Henry-Cotnam
Richard M. (digi...@serv.net) said...
>
>Calvin Henry-Cotnam wrote:
>> True. A more appropriate term for the two hot busses is "legs". You
>> connect the two different hots to different "legs" in the panel. This
>> term is more generic in that it applies to the two hots in a single
>> phase residential system (they are actually 180 degrees out-of-phase, but
>> this is mathematically considered the same phase), as well as panels
>> where more than one phase actually exists (commercial three-phase
>> installations and multi-family residential installations where the two
>> hots are actually two of three phases of a three-phase system
>
>very different.
Very true. What I described above is actaully called a Y-connection,
where the three phases have one side tied together to form a neutral
connection (at the centre of a 'Y', figuratively speaking). This gives
you three different line-to-neutral connections, and three different
line-to-line connections. Where the line-to-neutral voltage is 120 volts,
the line-to-line voltage is 208 volts. If you are familiar with
doing math on polar values, you can work it out for yourself.
>I'm not sure that all 240v devices will operate
>properly at 3ph leg-to-leg voltage.
For the most part, all consumer (ie: use in a home) products are fine.
Things that use 240 volts do so for one of two purposes: heat or motors.
Motors can be a problem, but there is generally little need of 240V motors.
A pool pump that can be configured to operate on 120 or 240 volts comes
to mind, but keep in mind that 2-of-3 phase distribution for dwellings
is something used in high-rise buildings, not in single family dwellings
(or duplexes, 3-plexes, etc), so the need for 240V motors is even lessened.
Clothes dryers have a motor, but (in all cases I've seen personally) the
motor is a 120 volt motor that is powered line-to-neutral. The same goes
for the rotissery (sp?) motor in a range or oven.
This leaves heating. When operating on 208 volts, a heating element is
derated to only 75% of its power rating for 240 volt operation. Baseboard
heaters come with a rating like "1500 W (240 V) / 1125 W (208 V)". This
means that your oven will take longer to heat up to the selected setting,
and your clothes might take about 1/3 longer time to dry. Our self-cleaning
oven usually has its cleaning cycle run for 4-5 hours, but if it were
operated on 240 volts, we could cut this time down by about 25%.
Regardless, the same energy is used. (energy = power * time)
Richard M.
I still don't understand you. If the receptacle is 30 amp and the
circuit is 30 amp, what is your position? I really am not understanding
your point.
Calvin Henry-Cotnam
Richard M. (digi...@serv.net) said...
>
>Steve Schlink wrote:
>>
>> "Richard M." <digi...@serv.net> wrote:
>>
>> >John, are you telling me that no 110v receptacle can be 30amp?
>>
>> No 115v recp. that you are going to plug a gas dryer into !
>
>I still don't understand you. If the receptacle is 30 amp and the
>circuit is 30 amp, what is your position? I really am not understanding
>your point.
The discussion was about providing an outlet for a gas dryer. These come
with plugs rated for 15A/115V and require an outlet of the same rating.
There most certainly are 30A/115V rated outlets, but they have nothing
to do with the discussion. I suspect that is what was meant here.
--
Calvin Henry-Cotnam, CATE | "That's what cheese is:
Ryerson Polytechnic University | gone-off milk with bugs and mould."
Toronto, Ontario, Canada | - Gareth Blackstock, Chef!
www.cate.ryerson.ca/~cal |
John Porter
Richard M. (digi...@serv.net) wrote:: >
: > >
: > >> I think he's trying to say that the 240V dryer circuit would be on
: > >> a 30 amp breaker, but the 110 volt receptacle must be on a 20 amp
: > >> or lower breaker.
: > >> John Porter
: > >> jpo...@bu.edu
: > >John, are you telling me that no 110v receptacle can be 30amp?
: >
: > No 115v recp. that you are going to plug a gas dryer into !
: I still don't understand you. If the receptacle is 30 amp and the
: circuit is 30 amp, what is your position? I really am not understanding
: your point.
I'm not entirely sure what is being asked here, but my original point
(or actually, the point I thought the other fellow was trying to make)
was that if what you're interested in connecting to the old dryer
circuit is a standard 15 or 20 amp receptacle, the circuit has to be
protected at 15 or 20 amps, respectively. Normally, any device has to
be protected at no more than the current it's rated for, although
there's an exception allowing you to use two or more 15A 120V
receptacles in a 20A 120V circuit. Naturally, if you have a 30A 120V
receptacle, you can use it on a circuit protected at 30 amps, but what
would you be plugging into it? I've never seen anything intended to
draw that kind of power running at 120V. There is a NEMA configuration
for it, though.
--
John Porter
jpo...@bu.edu