GFCI on a 12/3?

Status
Not open for further replies.
celtic

celtic

Senior Member
Location
NJ
A question was posed to be about using a 12/3 for the requirements of the SA circuit. I suggested that the shared neutral could create an issue and it would be better to run two seperate 12/2's. I was then asked to cite the article number that forbid it(GFI/shared neutral).

I did a quick search on the old CD version of the handbook - and came up short. Anyone have some insight (with accompanining references?)

Thanks.
 
Re: GFCI on a 12/3?

Celtic, this would only be a problem if GFCI breakers were being used. If the three conductor cable were used to supply circuits feeding the line side of GFCI receptacles there would be no problem.

Two wire could be used from any line fed GFCI receptacle to feed downstream protected devices.


Roger
 
Re: GFCI on a 12/3?

For arguements sake (and my own clarification)...if the 3-wire was used to supply multiple GFCI type recept.s...that would essentially become a multiwire BC.
The MWBC would then need the handles tied together on the CBs - correct?(and a tandam CB would be a bad idea for this application in general, correct?)
 
Re: GFCI on a 12/3?

When 12 or 14/3 is used on afci circuits the breaker will not hold,same as an afci circuit tied in with neutrals of another circuit afci or not.
That is why the industry came up with 12/14 -4.An acfi circuit must have the ungrounded conductor seperated from another circuit.
 
Re: GFCI on a 12/3?

We are talking about GFCI's...not AFCI's ~ which have not been accepted by NJ, nor mentioned by me until now.
 
Re: GFCI on a 12/3?

Celtic, it would be a MWBC, but you would not need a handle tie.

Only if the MWBC landed on devices sharing one yoke would this be necessary, see 210.4(B) or 210.7(C) if it fit.

Roger
 
Re: GFCI on a 12/3?

Thanks for pointing that out (same yoke).

Now here's another question - would YOU use a 12/3 to meet the requirements of 210.52(B)? Is the 12/3 acceptable?

I have never seen it done that way...always a minimum of 2 12/2's to the kitchen.
 
Re: GFCI on a 12/3?

I use 12/3 all the time. It saves homeruns which usually saves time. Run a 12/3 to a deep box, feed the gfi in that box with black, load side off that to other recepts, feed off the red to a gfi in another box. No need for two pole breakers just land circuits on opposite phases in panel and you are ok.
 
Re: GFCI on a 12/3?

As Roger has pointed out a multiwire circuit is fine for the small appliance circuits in the kitchen as long as, 1) it doesn?t land both circuits on one yoke and 2) the use of GFCI receptacles.
This is a popular method of wiring the kitchen in my area.
Side note, at times I will hit the microwave and laundry or bath the same way when the lay out is in the right order.
:)
 
Re: GFCI on a 12/3?

I gotta buy a book...I had one...but it was lost in the move :roll: (it was '93 edition anway)...it would surely help me out (Stallcup resi. wiring ~ illustrated...if I recall)
 
Re: GFCI on a 12/3?

Why would a two pole gfci breaker rather than gfci receptacles not work in this case? :confused:

[ June 09, 2005, 02:34 PM: Message edited by: electricmanscott ]
 
Re: GFCI on a 12/3?

Scott,
Why would a two pole gfci breaker rather than gfci receptacles not work in this case?
Click to expand...
As long as the 2 pole GFCI is for use on 3 wire circuits, there would not be any electrical problems, but the use of 2 pole GFCIs is not cost effective for this application.
Don
 
Re: GFCI on a 12/3?

Be sure to pigtail the neutral. It could be opened under a load if it were landed on the receptacle.

romeo
 
Re: GFCI on a 12/3?

Would sharing the neutral between one SA circuit and one Non-SA circuit be a violation?

Dave
 
Re: GFCI on a 12/3?

Originally posted by celtic:
Now here's another question - would YOU use a 12/3 to meet the requirements of 210.52(B)? Is the 12/3 acceptable?
Click to expand...
I wouldn't, just because cramming a GFI into a box with 2 12-2's and a 12-3 sounds like a real pain, IMO. :)
 
Re: GFCI on a 12/3?

Originally posted by georgestolz:
a box with 2 12-2's and a 12-3 sounds like a real pain, IMO. :)
Click to expand...
Now that your brought it up..it DOES sound like a pain...
2 12/2 = 4 Conductors
1 12/3 = 3C
All Grounds = 1C
Device = 2 C (How a GFI counts as 2 like a simple switch defies logic)
Total C = 10; 10 X 2.25 = 20.5 CU IN...that's very large of you.
 
Re: GFCI on a 12/3?

Originally posted by electricmanscott:
Just use the proper size box and it is not a pain at all. I do it all the time.
Click to expand...
Does carlton(or similar) make an old work box on 21" ?
 
Status
Not open for further replies.
Top