AFCI breakers on a 208 volt system.

[IRMILEY]

AFCI 2 pole breakers seem to only work with 180° phases. Has anyone figured out how to get an AFCI breaker on a 120/208 volt Multi Wire Branch Circuit?
My problem is that I have several of units with Home line and several with Murray. GE has application DET-719 using 2 single poles. Rewiring or putting in AFCI receptacles would be a nightmare.

 

[mbrooke]

AFCI 2 pole breakers seem to only work with 180° phases. Has anyone figured out how to get an AFCI breaker on a 120/208 volt Multi Wire Branch Circuit?
My problem is that I have several of units with Home line and several with Murray. GE has application DET-719 using 2 single poles. Rewiring or putting in AFCI receptacles would be a nightmare.

I'd go with the GE. My understanding is that two single pole AFCIs without GFP will not care about the phase shift associated with a 3 phase system or a single phase system derived from a 120/208Y power source.

 

[IRMILEY]

I figured as much. That still means changing out 30 load centers because the owner's wanted a few can lights.
I very surprised that only home line breakers points this issue out but only after you get the Breakers.

 

[mbrooke]

I figured as much. That still means changing out 30 load centers because the owner's wanted a few can lights.
I very surprised that only home line breakers points this issue out but only after you get the Breakers.

Have you tried AFCI receptacles? If the first device box is close enough to the panel you can do it. The other option is not pulling a permit.

 

[IRMILEY]

Nowhere to put them that makes sense. I'm​ being asked to come in after the fact. General contractor started the job and never finished. My other thought is to go look at the load and maybe with luck I can make it with combining the circuits the 1 single pole Circuit. They are just little units.

 

[K8MHZ]

Nowhere to put them that makes sense. I'm​ being asked to come in after the fact. General contractor started the job and never finished. My other thought is to go look at the load and maybe with luck I can make it with combining the circuits the 1 single pole Circuit. They are just little units.

Can you add a single pole breaker and move your circuit to that? Or is the panel already full?

 

[mbrooke]

Nowhere to put them that makes sense. I'm​ being asked to come in after the fact. General contractor started the job and never finished. My other thought is to go look at the load and maybe with luck I can make it with combining the circuits the 1 single pole Circuit. They are just little units.

Calc the circuit, you might be able to combine them. Often in resi mist circuits can indeed be combined as people generally wire above the 3va per foot rule. I feel your pain btw if the helps

 

[ActionDave]

Nowhere to put them that makes sense. I'm​ being asked to come in after the fact....

What about right at panel?

 

[wwhitney]

Do AFCI receptacles incorporate differential current ground fault detection? If so, they'd need to be downstream of the separation of the MWBC into separate 2 wire circuits.

Cheers, Wayne

 

[ActionDave]

Do AFCI receptacles incorporate differential current ground fault detection? If so, they'd need to be downstream of the separation of the MWBC into separate 2 wire circuits.

Cheers, Wayne

You are correct. I was not thinking things through.