I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?

On Dec 18, 10:44*pm, wrote:
* I would like to run some new outlets in my garage. *There is
currently a subpanel located there, the run will be fairly short. *I
have a section of armored cable which was left over from work at my
office that I'd like to use. *I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

* The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. * I'd like to use
it to run 4 20-amp circuits. *Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. *C and D would be run similarly. *That way, neither neutral
would ever carry more than 20 amps.

* I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. *Anybody want to chime in?

What about GFI outlets, since this is in a garage. I don't know the
code that well, but I think GFI's may be required for the outlets
since the garage floor could be wet.

What about GFI outlets, since this is in a garage. I don't know the
code that well, but I think GFI's may be required for the outlets
since the garage floor could be wet.

Yes, they are, I have that part covered.

Thanks a million. I'm glad to know that I'm not doing something I
shouldn't.

On Dec 18, 11:44*pm, wrote:
* I would like to run some new outlets in my garage. *There is
currently a subpanel located there, the run will be fairly short. *I
have a section of armored cable which was left over from work at my
office that I'd like to use. *I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

* The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. * I'd like to use
it to run 4 20-amp circuits. *Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. *C and D would be run similarly. *That way, neither neutral
would ever carry more than 20 amps.

* I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. *Anybody want to chime in?

Two hots (opposite each other) using the same neutral is commonly
called an 'Edison circuit'. AFAIK it is still OK to to wire new
circuits this way but there are problems.

I'm not an electrician but as I understand it if one breaker is shut
off the neutral can still carry current if the other breaker is on.
The outlets should be wired in such a way so that if an outlet on
circuit A is disconnected (for replacement or other reson) the neutral
will not be broken.

Do some googling on 'edison cicuit energized neutral' and you will
come up with many examples of how this type of circuit can be very
dangerous. Here is just one link:
http://www.hanford.gov/rl/?page=968&parent=334

Ganged breakers can prevent problems but think about the guy down the
road or yourself in 10 years when you're not exactly sure what you
did. Wire is cheap don't take the chance.

wrote in message
...
I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?


You will need to use larger outlet boxes to accommodate the larger and
additional conductors especially if you will be going from box to box. 4
11/16" x 2 1/8" square boxes will work best. Check tables 314.16(A) and (B).
The number ten wires will be difficult to attach to wiring devices.

I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


wrote in message
...
I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?

Stormin Mormon wrote:
I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

Everything in the post was "accepted colors". Nothing suggested colors
that are not "accepted".

I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?

For code questions, only your local code enforcement office can give you
the last word on this. Often they make changes/additions to the NEC and
that is what you'll have to work to. The NEC is MINIMUMs: Local offices
often add to them.
Give them a call; they're usually more than happy to discuss it with
people. You can also make certain of the permit situation at the same
time; you may need to pull a permit but in your case it'll be a very
simple process as will the inspection.

Twayne

You will need to use larger outlet boxes to accommodate the larger and
additional conductors especially if you will be going from box to box. 4
11/16" x 2 1/8" square boxes will work best. Check tables 314.16(A) and (B).
The number ten wires will be difficult to attach to wiring devices.

I'm planning on either using two two-gang boxes, or a single four-gang
box. I'm only entering 2 10's, and 6 12's, I think that just about
any two-gang has enough cubic inches to qualify for those.

I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

Everything in the post was "accepted colors". Nothing suggested colors
that are not "accepted".

Yeah. I'd be pretty leery of an electrician that didn't understand
that setup... but then again, I'm used to dealing with electricians
that come and work on our 3-phase, 440V stuff.

wrote in message
...
You will need to use larger outlet boxes to accommodate the larger and
additional conductors especially if you will be going from box to box. 4
11/16" x 2 1/8" square boxes will work best. Check tables 314.16(A) and
(B).
The number ten wires will be difficult to attach to wiring devices.

I'm planning on either using two two-gang boxes, or a single four-gang
box. I'm only entering 2 10's, and 6 12's, I think that just about
any two-gang has enough cubic inches to qualify for those.



*A deduction of two conductors must be made for each wiring device based on
the largest conductor. A deduction of one conductor is made for clamps
inside the box. 2.25 cubic inches is required for each #12. 2.5 cubic
inches is required for each #10.

4 x 2.5 = 10 cubic inches for the devices.
2 x 2.5 = 5 cubic inches for the two #10's.
6 x 2.25 = 13.5 cubic inches for the six #12's
1 x 2.5 = 2.5 cubic inches for the clamp.
Total = 31 cubic inches.

If you use 3.5" deep gem boxes ganged together you should be fine. Don't
skimp on cubic inches to save a buck. It will be a pain pushing all those
wires into the box with GFI's attached and #10 wire.

"Limp Arbor" wrote in message
...
On Dec 18, 11:44 pm, wrote:
I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?

Two hots (opposite each other) using the same neutral is commonly
called an 'Edison circuit'. AFAIK it is still OK to to wire new
circuits this way but there are problems.

I'm not an electrician but as I understand it if one breaker is shut
off the neutral can still carry current if the other breaker is on.
The outlets should be wired in such a way so that if an outlet on
circuit A is disconnected (for replacement or other reson) the neutral
will not be broken.

Do some googling on 'edison cicuit energized neutral' and you will
come up with many examples of how this type of circuit can be very
dangerous. Here is just one link:
http://www.hanford.gov/rl/?page=968&parent=334

Ganged breakers can prevent problems but think about the guy down the
road or yourself in 10 years when you're not exactly sure what you
did. Wire is cheap don't take the chance.



*The 2008 code requires a two pole breaker for this set-up.

On Dec 19, 2:55*pm, "John Grabowski" wrote:
"Limp Arbor" wrote in message

...
On Dec 18, 11:44 pm, wrote:





I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?

Two hots (opposite each other) using the same neutral is commonly
called an 'Edison circuit'. *AFAIK it is still OK to to wire new
circuits this way but there are problems.

I'm not an electrician but as I understand it if one breaker is shut
off the neutral can still carry current if the other breaker is on.
The outlets should be wired in such a way so that if an outlet on
circuit A is disconnected (for replacement or other reson) the neutral
will not be broken.

Do some googling on 'edison cicuit energized neutral' and you will
come up with many examples of how this type of circuit can be very
dangerous. *Here is just one link:http://www.hanford.gov/rl/?page=968&parent=334

Ganged breakers can prevent problems but think about the guy down the
road or yourself in 10 years when you're not exactly sure what you
did. *Wire is cheap don't take the chance.

*The 2008 code requires a two pole breaker for this set-up.- Hide quoted text -



Does NEC require a de-rating for the neutral wire current?

If you have 20 Amp breaker on phase A and a 20 Amp breaker on phase B
and both phases share a neutral, you would think that the max current
the neutral could ever see is 20 Amps, but that is wrong. Due to
power factor issues there can be more than 20 Amps flowing through the
common neutral wire.

I don't think this will be a problem for the OP in his garage but it
was a problem in large office buildings with large numbers of early
PCs. I am curious if the NEC codes address this question?

Mark

I could be wrong, but I think you may also need to derate the wire sizes
because of multiple circuits in the cable, i.e.
treating the 12 ga cables like 15 amp, regarding loads and the breaker.

On Dec 19, 3:16�pm, "bill allemann"
wrote:
I could be wrong, but I think you may also need to derate the wire sizes
because of multiple circuits in the cable, i.e.
�treating the 12 ga cables like 15 amp, regarding loads and the breaker.

yeah some derating will be necessary,

besides which copper price is down, run a new heavy whatever cable
like a 6 gauge to a sub panel and save yourself a lot of hassle, and
lots of questions at home resale where nervous home inspectors will
jump all over your cabling.

I ran some 10 gauge once for outdoor lights left over from my sheds
power line run, and regretted it . how miserable to work with for
lowly lighting

needed 10 gauge with 20 amp breaker for shed cause of long run, and
possible use of heavy load table saw out there in future.

On 2008-12-19, John Grabowski wrote:

*The 2008 code requires a two pole breaker for this set-up.

No, it requires a simultaneous disconnect, e.g. a handle tie. It does
not require a simultaneous trip.

Cheers, Wayne

On 2008-12-19, bill allemann wrote:

I could be wrong, but I think you may also need to derate the wire
sizes because of multiple circuits in the cable, i.e. treating the
12 ga cables like 15 amp, regarding loads and the breaker.

It is necessary to derate whenever you have more than 3 current
carrying conductors in a bundle or conduit. However, the ampacity of
small conductors with 90 degree insulation is higher than the
conventional maximum OCPD. For example, for most branch circuits, #14
can not be fused at higher than 15 amps, but for purposes of derating
the ampacity of #14 with 90 degree insulation is 20 amps. So as long
as your derating factor is at least 0.75, you still get an ampacity of
at least 15 amps. The upshot is that for #10 and smaller, with 6
conductors, there is no need to decrease the OCPD from the usual.

Yours, Wayne

wrote in message
...
On Dec 19, 2:55 pm, "John Grabowski" wrote:
"Limp Arbor" wrote in message

...
On Dec 18, 11:44 pm, wrote:





I would like to run some new outlets in my garage. There is
currently a subpanel located there, the run will be fairly short. I
have a section of armored cable which was left over from work at my
office that I'd like to use. I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. I'd like to use
it to run 4 20-amp circuits. Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. C and D would be run similarly. That way, neither neutral
would ever carry more than 20 amps.

I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. Anybody want to chime in?

Two hots (opposite each other) using the same neutral is commonly
called an 'Edison circuit'. AFAIK it is still OK to to wire new
circuits this way but there are problems.

I'm not an electrician but as I understand it if one breaker is shut
off the neutral can still carry current if the other breaker is on.
The outlets should be wired in such a way so that if an outlet on
circuit A is disconnected (for replacement or other reson) the neutral
will not be broken.

Do some googling on 'edison cicuit energized neutral' and you will
come up with many examples of how this type of circuit can be very
dangerous. Here is just one
link:http://www.hanford.gov/rl/?page=968&parent=334

Ganged breakers can prevent problems but think about the guy down the
road or yourself in 10 years when you're not exactly sure what you
did. Wire is cheap don't take the chance.

*The 2008 code requires a two pole breaker for this set-up.- Hide quoted
text -



Does NEC require a de-rating for the neutral wire current?

If you have 20 Amp breaker on phase A and a 20 Amp breaker on phase B
and both phases share a neutral, you would think that the max current
the neutral could ever see is 20 Amps, but that is wrong. Due to
power factor issues there can be more than 20 Amps flowing through the
common neutral wire.

I don't think this will be a problem for the OP in his garage but it
was a problem in large office buildings with large numbers of early
PCs. I am curious if the NEC codes address this question?



*The code does address nonlinear loads, but I forget specifically in what
chapters. Article 210.4 does mention them as a FPN.

On Dec 19, 9:53*am, Limp Arbor wrote:
On Dec 18, 11:44*pm, wrote:





* I would like to run some new outlets in my garage. *There is
currently a subpanel located there, the run will be fairly short. *I
have a section of armored cable which was left over from work at my
office that I'd like to use. *I'm thinking of using a setup which I
have seen used in other houses, but want to run past you first.

* The armored cable has two 10-gauge (white & gray), 4 12-gauge
"hots" (various colors), and two 12-gauge grounds. * I'd like to use
it to run 4 20-amp circuits. *Circuits A and B would come off of
opposite phases, and share one of the neutrals and one of the
grounds. *C and D would be run similarly. *That way, neither neutral
would ever carry more than 20 amps.

* I know that I would never exceed rated ampacity for any conductor,
but I do not know the NEC well enough to say whether that will meet
current code or not. *Anybody want to chime in?

Two hots (opposite each other) using the same neutral is commonly
called an 'Edison circuit'. *AFAIK it is still OK to to wire new
circuits this way but there are problems.

I'm not an electrician but as I understand it if one breaker is shut
off the neutral can still carry current if the other breaker is on.
The outlets should be wired in such a way so that if an outlet on
circuit A is disconnected (for replacement or other reson) the neutral
will not be broken.

Do some googling on 'edison cicuit energized neutral' and you will
come up with many examples of how this type of circuit can be very
dangerous. *Here is just one link:http://www.hanford.gov/rl/?page=968&parent=334

Ganged breakers can prevent problems but think about the guy down the
road or yourself in 10 years when you're not exactly sure what you
did. *Wire is cheap don't take the chance.- Hide quoted text -

- Show quoted text -

Quote: "I'm not an electrician but as I understand it if one breaker
is shut
off the neutral can still carry current if the other breaker is on".

Suggestion: You use a double pole breaker. This disconnects 'both' the
hots associated with that Edison circuit and its' single neutral. This
is how they are wired in our house.

The two hots are the two 'legs' (sometimes and often incorrectly
called 'phases') of the supply. The 'plus and minus' ** 115 volts,
usually being the two ends of the single phase 230 volt centre tapped
output winding of the local distribution transformer.

** Being AC this + and - business is, strictly speaking, incorrect.
But have found it a way of explaining three wire (and ground of
course) 115/230 volt systems business to certain people (usually my
neighbours!) who don't understand electricity very well. Certainly not
those here present of course.

On Fri, 19 Dec 2008 08:31:25 -0500, "Stormin Mormon"
wrote:

I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.


By code all the wires will need to be "tagged" - all neutrals white,
all lines black (or possibly red) - at BOTH ends.

On Fri, 19 Dec 2008 10:19:41 -0800 (PST), wrote:

I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

Everything in the post was "accepted colors". Nothing suggested colors
that are not "accepted".

Yeah. I'd be pretty leery of an electrician that didn't understand
that setup... but then again, I'm used to dealing with electricians
that come and work on our 3-phase, 440V stuff.


Residential electricians deal with black, white, red and green. ( or
shades there-of) So grey and mauve could be black and red?

On Dec 20, 6:25*pm, wrote:
On Fri, 19 Dec 2008 10:19:41 -0800 (PST), wrote:
I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

Everything in the post was "accepted colors". Nothing suggested colors
that are not "accepted".

Yeah. *I'd be pretty leery of an electrician that didn't understand
that setup... but then again, I'm used to dealing with electricians
that come and work on our 3-phase, 440V stuff.

Residential electricians deal with black, white, red and green. ( or
shades there-of) So grey and mauve could be black and red?

Agree.
But have met electricians who know all about current practice of how
to wire, how much slack, frequency of stapling etc. etc. but haven't
got a clue about the ratio between RMS and peak voltage, or why phase
to phase voltage is different from phase to neutral voltage, for
example in 3 phase service in a supermarket lighting sytem and have no
idea how a GFI works.

On Sat, 20 Dec 2008 16:59:28 -0800 (PST), terry
wrote:

On Dec 20, 6:25Â*pm, wrote:
On Fri, 19 Dec 2008 10:19:41 -0800 (PST), wrote:
I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

Everything in the post was "accepted colors". Nothing suggested colors
that are not "accepted".

Yeah. Â*I'd be pretty leery of an electrician that didn't understand
that setup... but then again, I'm used to dealing with electricians
that come and work on our 3-phase, 440V stuff.

Residential electricians deal with black, white, red and green. ( or
shades there-of) So grey and mauve could be black and red?

Agree.
But have met electricians who know all about current practice of how
to wire, how much slack, frequency of stapling etc. etc. but haven't
got a clue about the ratio between RMS and peak voltage, or why phase
to phase voltage is different from phase to neutral voltage, for
example in 3 phase service in a supermarket lighting sytem and have no
idea how a GFI works.


And they need to know this theory to effectivey and safely wire a
house? Residential electricians do not need to know 3 phase. And they
need to know how to wire a FFI, but do not need to know the nuts and
bolts of how it works.

That's why there are different licences - a lot of industrial
electricians would have a heck of a time wiring a house. No conduit?
No BX? The wires go THROUGH the 2X4 studs? No raceways?

How the heck am I supposed to rout the wires?

besides which copper price is down, run a new heavy whatever cable
like a 6 gauge to a sub panel and save yourself a lot of hassle

That is what I have previously done, 6-gauge to a subpanel.
Initially, I only brought out two 120V circuits for outlets, and a
220V circuit for lighting. But, it's getting *really* cold, and a
friend will be working in there with me. With multiple lathes,
halogen work lights, and space heaters working at the same time, it
was time for more outlets.

Now, with 6 20-amp circuits for 120V outlets, I'm more than set. If
I needed more than that, I'd need a bigger run to the subpanel - and
since I only have a 100A service on the house, pulling more than 50
amps just to the garage wouldn't be that good of an idea.

Doing one splice in each box with the 10-gauge wasn't bad at all.
Everything went quite well, with no surprises.

wrote:
On Sat, 20 Dec 2008 16:25:58 -0500, wrote:

On Fri, 19 Dec 2008 10:19:41 -0800 (PST), wrote:

I'd not want to do that. Later electricians will find mauve, purple, fuscia
and olive wires. And not know which one is hot, or neutral. For the one time
expense, I'd suggest to buy new wire, and stick to the accepted colors for
hot, ground, and neutral.

Everything in the post was "accepted colors". Nothing suggested colors
that are not "accepted".

Yeah. I'd be pretty leery of an electrician that didn't understand
that setup... but then again, I'm used to dealing with electricians
that come and work on our 3-phase, 440V stuff.

Residential electricians deal with black, white, red and green. ( or
shades there-of) So grey and mauve could be black and red?

Grounds have to be green, green with a yellow stripe or bare
Neutrals have to be gray or white.
No other colors are specified and a "hot" can use anything else.
In a commercial installation you might see 10 or more colors for the
hots.

And it is inconceivable a licensed electrician, residential or other,
wouldn't know that.

--
bud--