This won't work at all. Your GFCI's will trip continuously when these circuits are used. You can not share a neutral on the protected (LOAD) side of a GFCI with another circuit (GFCI or not). You also can't connect the neutral on the protected side to the neutral on the unprotected side.

Your options are:

1. Run a separate neutral for each protected circuit. You can share the neutral (multiwire circuit) up to the point where the GFCI is. After that you need to keep the neutrals separate.
2. Use GFCI receptacles at each location such that there is nothing on the protected side (other than whatever is plugged into the GFCI receptacle itself).
3. Use a two-pole with load neutral GFCI in the panel. This is required if you're going to split individual duplex receptacles across both circuits (uncommon in the US, but often required in Canada).

You can run the 12/3 from the breakers to the first GFCI, then run 12/2 from each GFCI to the protected receptacles downstream. You cannot continue with 12/3 after the first GFCI unless you wire to the line side only and use a GFCI at each location.

Also, you should use a double-pole breaker to ensure you are on opposite legs of the panel.

* Posted by normel (My Page) on
Wed, Feb 4, 09 at 11:05

You can run the 12/3 from the breakers to the first GFCI, then run 12/2 from each GFCI to the protected receptacles downstream. You cannot continue with 12/3 after the first GFCI unless you wire to the line side only and use a GFCI at each location.

Also, you should use a double-pole breaker to ensure you are on opposite legs of the panel.

(OP)
This guy is giving out bad advise. I advice you to disregard what he is saying because he is going to get someone hurt.

Ok there are no legs in the panel as the about claims.... They are called phases.. You will have a A phase and a B phase. In this citation you CAN share the neutrals. If you are going to run 12/3 with 2 circuits you have to run 12/3 the WHOLE RUN to carry both of your circuits. The 2nd circuit will pass thru the Duplexs until it terminates at the 2nd GFI which would be your 2nd circuit. From GFI #1 circuit to duplex (12/2) is all u will need (GFI Line To Duplex LOAD)same with GFI #2 circuit to duplex. If you do not run 12/3 all the way through you can not get power to your 2nd circuit unless you run 2 runs of 12/2 from panel... Stick with the 12/3. I hope that helps
Take Care

Whether you call them legs or phases is just semantics. There was no confusion in normel's post that needed a discussion of those names.

normel and electricman are both suggesting a 12/3 multiwire branch circuit feeding 2 GFCI receptacles. The cable between the first and second GFCI could be 12/2, just by tying together the incoming 12/3 neutral, a pigtail to the receptacle neutral, and the outgoing 12/2 neutral. Code requires the pigtail in this case rather than putting all neutrals on the receptacle. The 12/3 second hot and the outgoing 12/2 hot are wired together and have nothing to do with the receptacle in the first box.

As your buddy normel quotes "You cannot continue with 12/3 after the first GFCI unless you wire to the line side only and use a GFCI at each location."

That is completely wrong and you must carry the 12/3 the entire way. Also you might understand legs/phases tho the OP may not. Like pigtail/slang.

OP
He is talking about taking all the wires and then twist them together another wire so that you have 1 hot/1neutral/ and one ground attaching to the GFI or Duplex. That is what a pigtail is. The reason for this is if you attach 3 neutrals or hots to a single GFI/Duplex receptacle one of the two goes bad(GFCI or Duple) the current will not flow and all of the receptacles will not work. If you pigtail, only the bad plug will be down. The rest will work.

sorry electricman but i agree with normel. you can't continue to use the 12/3 past the first GFCI cause the neutral won't be balanced with either hot and thus trip the GFCIs. now if the OP got a 2 pole GFCI breaker there would be no worries or confusion at all.

to do it with 2 GFCI recpts you run 12/3 to the first location. pigtail neutral, 1 hot, and ground to that GFCI. pigtail ground and nutral and the other hot to teh feed to teh 2nd GFCI. then hook the feed for the rest of the outlets protected by teh 1st GFCI to LOAD side of it. since the neutrals can't be shared AFTER the first device, you must run 2 cable runs. if there were not anything hooked to the load side of the first GFCI, you could continue the 12/3 and just not connect the unused wire, but that is a waste of money.

I agree with electricman and billhart here. Though electric man you would wire the duplex's from the LOAD side of the GFCI, not the LINE, honest mistake. The 12/3 must pass through to enable the 2nd circuit to work. It would just be passing through until it hit the 2nd GFCI then if would connect there. You would use 12/2 to connect the GFCIS to the Receptacles. You can share the neutrals also. This is not a problem.

"Ok there are no legs in the panel as the about claims.... They are called phases."

Better study some more.
A 120/240 V residential service is SINGLE PHASE.
The two hots should be referred to as legs (or anything except phases) to indicate they are NOT separate phases.
An induction motor fed from either 120 V or 240 V single phase requires a start capacitor to create a phase shifted current for the start winding. Without the start capacitor the motor has zero starting torque and cannot come up to speed.

Two phase power has NOT been used in the US for many years. It requires four wires to deliver (no sharing a same size neutral like 3 phase delta) and has voltage waveforms 90 degrees apart.

Three phase power require only three wires for a delta connection, four wires for a Y. The phases are 120 degrees apart. If the separate phase loads are identical there is zero neutral current.

We also have unequal voltage 3 phase services (the 'stinger' systems) when 3 phase power is needed for some loads, but 120/240 V single phase is also needed in large amounts.

I'll stand by my first post.

Electricman, you are completely and totally wrong in everything you said here.

Attempting to connect a shared neutral to the load side of a single pole GFCI will cause it to trip as soon as any current flows through it. You can not use any sort of multiwire circuit after a single pole GFCI.

The only way to make a multiwire circuit work is to use a two pole GFCI (e.g., a GFCI two pole breaker).

They're not phases. The code calls it SINGLE PHASE. It doesn't say leg in most places (although it does appear) either but leg is commonly understood by real electricians and engineers to be any output of a distribution transformer.

if it is pahses for standard household 240v, why are they labeled L1 and L2? shouldn't it be P1 and P2?

I pondered this original question a few weeks ago, my kitchen outlets are split 15a/15a as was the procedure here in Canada in the 80's but there was no gfci requirement and some are very close to the sink which under current code (pun intended) requires a gfci. The individual outlets are cheap enough but the ones I've seen do not have the ability to split the tab between the outlets and run on two circuits, I too of course have the shared neutral. Unless there is a GFCI outlet that has that tab, I will have to go with a two pole or pair of 15a gfci breakers. I doubt the original poster will have any choice but to go this route also.

As for the phase/leg nomenclature, I certainly agree it's not a second 'phase' perhaps "tap" is a better term since the setup is basically a multitap transformer out in the street....

" some are very close to the sink which under current code (pun intended) requires a gfci."

It only requires a GFCI if you are modifying the circuit. If it didn't require a GFCI when the circuit was built and you don't mess with it it is still up to code and does not require any changes.

And if you DO change it, you will need a double pole 120/240V GFCI breaker. Two individual breakers on a MWBC will not work.

normel is right and to reiterate, the 2-pole GFCI breaker must have the load neutral for this to work. They're made both ways by some manufacturers (straight 240 and 120/240).

"If you are going to run 12/3 with 2 circuits you have to run 12/3 the WHOLE RUN to carry both of your circuits. The 2nd circuit will pass thru the Duplexs until it terminates at the 2nd GFI which would be your 2nd circuit."

And the GFI will trip anytime a load is placed on your "2nd circuit" - you cannot share the neutral on the load side of the 1st GFI.

" I hope that helps "

No, you giving the wrong advice time and time again does not help.

I am always curious:The OP, one Sharff, preposes the wiring of GFCIs that elicits 20 responces, some of which question the intelligent and motives of other posters. Wonder what the OP decided to do? We rarly hear.

Who cares about the return on one neutral - the problem lies in the fact that you CANNOT run a shared neutral on the load side of a GFCI like Electricman said = period and end of discussion.

The very first reply has all the correct information in it.
The other information with the sole exception of the so-called "electric man" say the same thing as the first one with more elaboration.

Since you asked, I'm the OP and the first response is correct, it doesn't work.

What I will do is put a GFIC receptacle at each location rather than the "pass through" method.

Thanks for your responses, the amount of information offered here is great.

Al Sharff

it would be cheaper to just get the 2pole GFCI breaker than to put a bunch of individual GFCI outlets there. which was part of the first response.

HEY! The second response was correct too! :)

I was assuming the OP has an arrangement like mine where the tab between the two outlets on each power point has been broken and the black feeds one, and the red feeds the other. If that's the case, individual outlets can't be used. In my case, I would go with the individual outlets since it'd be cheaper and easier than replacing the breaker, but it wouldn't work.

If OP's outlets aren't split, if that's the term, then he/she has either option.

For god's sake, give it a rest!

FIRST OF ALL , IS THIS A WET LOCATION? DO YOU EVEN NEED G.F.I. PROTECTION ? BUT MOST OF ALL YOU CAN NOT RUN A 3 WIRE ON A G.F.C.I. PROTECTED CIRCUIT BECAUSE YOU WILL ABSOLUTLY HAVE A NEUTRAL INBALANCE ESPECIALLY WHEN THERE ARE 2 SEPERATE LOADS BEING DRAWN AT THE SAME TIME INSTEAD OF ARGUING GENTLEMEN .LETS CHECK OUR CODE BOOKS

electricsmylove, what are you using? an Apple II?! If so, the fancy slot #3 80-column text mode does allow lower-case letters, and fits more text on the screen to boot!

Elsewise, try pressing the "CAPS LOCK" button on the left of your keyboard. You (or, rather, we) want it off.

You HAVE to be kidding me! My post about his all caps was removed. And also the comment after it.
Give me a BREAK! My post was completely polite.
WHY was it removed???

Actually the forum page shows 35 replies, yet only 27 are here.
Why were EIGHT posts removed from this thread???

To keep on the relevant topic, in the US "wet location" isn't a criteria for GFCI requirements. The code specifically calls out locations where receptacles must be protected: countertops, bathrooms, garages, outside, unfinished basements, etc...

All countertops? It is a little different here in Canada although my book is probably two years old and may have changed (and it may be a unified code, not just British Columbia) - you must have no more than 900mm/35.4" between outlets but as for GFI it says "washbasins" yet my kitchen section does not mention them, where it says "washbasins" it says all outlets gfi protected within 3m which for most kitchens would be the majority of outlets, in which case why would you not do them all; and 20amp outlets are permitted but lighting is not allowed to be on that 20a circuit.

With the proliferation of espresso machines currently, and the emergence of plumbed-in models, I can see 20 amp and even 240v (I could have brought my old espresso machine with me from Australia) becoming popular, and no doubt in higher end kitchens there will be an espresso nook with specialised outlets and a water box recess thingy like is provided for fridges, eventually. My current machine just uses a water tank though. A gfci for an espresso machine seems like a good idea to me, water and electricity come very close together in them (and even closer when they start to leak like mine has)

I still don't know if you can get GFI outlets that can be divided though - all the ones I've seen have no provision to separate the two individual outlets. For me at least, it's gfci two pole breakers. Probably around $100 each.

Well, all KITCHEN countertops. There's no exception for distance from the sink.

240V receptacles are not included in this requirement.

Dedicated appliance receptacles in their own space (like the one behind my cabinet mounted Miele Coffee Station) also do not need to be protected.

The original poster is NOT in Canada so he doesn't have to worry about the goofy yoke splitting requirement.

As I have said and everybody else has said. A receptacle GFCI can't be used for the multiwire circuit like you are describing. All the current carrying conductors must pass through the same GFCI in order for it to work. That means a GFCI breaker with load neutral for you.

pjb999, the reference I made a long time ago to using individual gfci outlets at every location along a shared-neutral circuit was NOT intended to imply splitting the gfci outlets. The suggestion was that BOTH sockets on the first receptacle were on leg A, then BOTH on the second were B, then BOTH on the third were A, then BOTH on the fourth were B, etc -- with the boxes alternating legs rather than the receptacles themselves being split-wired.

I've sat here and bit my tongue while that miscommunication enlarged itself long enough.

Thanks for the clarification. With the talk of shared neutrals I assumed it was a split yoke setup.

Personally I think the split yoke this IS stupid, and the arrangement described herein makes more sense. It's also safer in that it's not relying on someone to remember to use tie bars on the breaker so the box isn't half hot.

Handle ties are required in split-yoke setups in the US.

A two-pole GFCI breaker is going to have a handle tie anyhow (well it's going to probably one handle for both poles).