# MWBC GE AFCI/GFCI tripping



## HackWork (Oct 2, 2009)

electricdrummer said:


> Hey guys got a quick one for ya on this Sunday morning. I recently rewired a home from scratch with the laundry room and 3 full baths on the second floor all next to each other. After discussing my plan to use MWBC's with my supplier, *i was told i could share neutrals with the use of GE AFCI/GFCI breakers with tie handles to achieve my goal of using 2 12/3's to hit the laundry and three bathrooms*, having them all on their own 20A dedicated circuits. Problem i am having is that i can only get one half of each MWBC to hold, and whenever i put a load on the other half, breaker trips. I have traced everything back to the panel to the first box and everything looks fine. I'm now at the point of installing AFCI only breakers and putting GFCI receptacles in the laundry and bathrooms to alleviate the problem, that's my plan b. I'm heading back today to continue troubleshooting and cant shake this gut feeling that i am close to solving this problem. I need help. Any insight would be greatly appreciated. Thanks all!


"_i was told i could share neutrals with the use of GE AFCI/GFCI *breakers with tie handles* to achieve my goal of using 2 12/3's to hit the laundry and three bathrooms_"

Are you using 2-pole AFCI/GFCI breakers made for this purpose? Or 2 single poles with a handle tie that you installed between them?


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## J F Go (Mar 1, 2014)

It is not possible to share the neutral from two different circuits with AFCI/GFCI breaker. It will trip every time. Supply house guys aren't really the best source of information to understand how something works, IMO. MWBC conductors, for what you did, would have been you using the multi conductor with two neutrals in the sheath.


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## Signal1 (Feb 10, 2016)

J F Go said:


> It is not possible to share the neutral from two different circuits with AFCI/GFCI breaker. It will trip every time. Supply house guys aren't really the best source of information to understand how something works, IMO. MWBC conductors, for what you did, would have been you using the multi conductor with two neutrals in the sheath.


He said was using the new GE breakers, which you can in fact share a neutral at least for the AFCI ones, not sure about the Dual function GFCI/AFCI.
https://www.geindustrial.com/print/node/234861

Great for retrofits, however the OP said "rewired from scratch", hmmm, I'd give everyone a neutral while I had the chance.


"_He said was using the new GE breakers_",
edit: I stand corrected, the OP didn't say this.


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## electricdrummer (May 23, 2013)

HackWork said:


> "_i was told i could share neutrals with the use of GE AFCI/GFCI *breakers with tie handles* to achieve my goal of using 2 12/3's to hit the laundry and three bathrooms_"
> 
> Are you using 2-pole AFCI/GFCI breakers made for this purpose? Or 2 single poles with a handle tie that you installed between them?



thanks hack! that's it! I will pick up 2pole breakers first thing monday morning.


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## Service Call (Jul 9, 2011)

Nope. Need a 2 pole breaker. 2 singles tied together ain’t gonna work. 


Sent from my iPhone using Tapatalk


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## nrp3 (Jan 24, 2009)

I have used a handle tie with two single pole GE AFCI breakers, but not the Dual function type. I think the Dual function is the problem. If you have a real two pole Dual function made the same way one is that we typically use on a hot tub (if there is such a thing), you'd probably be ok. I think you are going to have to go back to GFCI at the point of use, provided it's accessible.


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## JoeSparky (Mar 25, 2010)

GE's regular combination type non gfci arc fault breakers no longer have any kind of ground fault protection. The handle tie works just fine for them. A gfci breaker depends on the neutral from each circuit to be landed on the device. They measure the current usage between hot and neutral. More then 5 mA difference and they trip. This is why one of your breakers is tripping. You need 2 pole breakers in this application.
I don't think anyone has a 2 pole dual function breaker yet. It's a day late and a dollar short for this job, but 2 12/2 home runs are only $10 more in material then 1 12/3. You are now going to spend $25 in GFCI outlets to save $10 in wire


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## HackWork (Oct 2, 2009)

So you guys are saying that you can use 2 standard single pole combo AFCI breakers (no GFCI) with a handle tie to power both legs of a MWBC and it will work without issue?

I know that if you touch the neutral to ground of a circuit fed with an AFCI it will trip, so I didn't think 2 of them would work with a shared neutral of a MWBC.


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## JoeSparky (Mar 25, 2010)

HackWork said:


> So you guys are saying that you can use 2 standard single pole combo AFCI breakers (no GFCI) with a handle tie to power both legs of a MWBC and it will work without issue?



GE has specifically removed any ground fault protection from their standard combo single pole arc fault breakers. MWBC or not, you don't need to land the neutral on their afci breakers
http://apps.geindustrial.com/publibrary/checkout/DEQ-234?TNR=FAQs|DEQ-234|PDF&filename=DEQ-234.PDF


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## nrp3 (Jan 24, 2009)

I've done this at least half a dozen times and have it in my own house with the GE AFCI breakers.


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## emtnut (Mar 1, 2015)

As Signal1 mentioned, GE took the GFP out of the their AFCI breakers. So you could use 2 single poles with a tie bar and not have a problem.

AFAIK, they didn't take the GFP out of the GFCI :vs_laugh: 

BR took the GFP out of their AFCI's as well, but it's not documented (at least anywhere I can find)

So for a dual function, OP would need a 2 pole breaker.


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## JoeSparky (Mar 25, 2010)

Now, if we can only convince them to take the AFCI protection out of AFCI breakers :vs_laugh:


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