AFCI - Multiwire branch circuits

[dana1028]

Are there any AFCI breakers [2-pole] yet available for multiwire branch circuits?

Thank you,

 

[jumper]

Rumor has it that GE and Siemens make them.

 

[gotmud]

yup....

 

[Dennis Alwon]

Ge uses 2 single poles with breaker tie. That is exclusive to GE. I don't believe sq. D QO panels make them or so a member has been told.

 

[bobserrano]

The info I got from the field is that 2 single pole arc faults with handle ties will not work with shared neutrals. I heard that Square D makes a 2 pole arc fault that is made for shared neutrals.

 

[220/221]

I saw one....I think it was Cutler Hammer BR series (it was in a Homeline panel).

Someone mistakenly ran a 3 wire HR (new construction) and got away with it.

Half of the breaker failed BTW. Don't ask what I used to replace it.

 

[ActionDave]

The info I got from the field is that 2 single pole arc faults with handle ties will not work with shared neutrals.

That is correct, with this exception.

I heard that Square D makes a 2 pole arc fault that is made for shared neutrals.

Nope. But these guys make one, i.e. what Jumper and Dennis said.

 

[al hildenbrand]

Are there any AFCI breakers [2-pole] yet available for multiwire branch circuits?

If GE and its MOD 3 Combination-type single pole AFCI are any indication of what other manufacturer's will copy and make for us to install, then, in the future, providing AFCI protection for part or all of a multiwire branch circuit will be no big deal.

Look carefully at the wiriing diagram in the GE tech article about their handle tied single pole MOD 3 combination AFCI.

Click HERE.

Note that one AFCI has no neutral connected to it! This GE AFCI is a whole new generation of product, in that the ground fault sensitivity has been removed.

These breakers have been sold since the middle of last year. No additional price.

 

[Dennis Alwon]

If GE and its MOD 3 Combination-type single pole AFCI are any indication of what other manufacturer's will copy and make for us to install, then, in the future, providing AFCI protection for part or all of a multiwire branch circuit will be no big deal.

Look carefully at the wiriing diagram in the GE tech article about their handle tied single pole MOD 3 combination AFCI.

Click HERE.

Note that one AFCI has no neutral connected to it! This GE AFCI is a whole new generation of product, in that the ground fault sensitivity has been removed.

These breakers have been sold since the middle of last year. No additional price.

I have not needed this as I never use mwbc in a residence but it is convenient in that you don't need to stock different parts. I posted that exact hookup awhile ago and the product was available then. FWIW, these are not special single pole afci. They are the standard afci put together with ties.

 

[al hildenbrand]

I have not needed this as I never use mwbc in a residence but it is convenient in that you don't need to stock different parts. I posted that exact hookup awhile ago and the product was available then. FWIW, these are not special single pole afci. They are the standard afci put together with ties.

As enforcement of the 2011 NEC is phased in, the value of this type of AFCI will increase. Many existing dwellings contain MWBC homeruns to the service, and they may well be serving parts of the dwelling that are included in the list of areas / rooms in 2011 NEC 210.12. Repair, replacement and / or extension of these circuits become somewhat simpler with the capabilities of the GE MOD 3 combination AFCI (as we all wait for the receptacle type AFCI to arrive.)