Panel Replacement & MWBC/AFCI

[dgrey]

I replaced a panel this weekend that had one 15 Amp MWBC feeding two bedrooms. My question is with the arc fault breaker that is required. I cant seperate the circuits onto two AFCI due to the one neutral and a two pole AFCI is not produced! How does the code account for this common wiring practice in older homes if it does at all. I initially placed both ungrounded conductors on one AFCI but nowI believe I have an overloading problem.

 

[LarryFine]

We have not (yet) had to add AFCI's to existing circuits with panel replacements.

Two options that I see if you can't find 2p AFCI's:

1. Run at least one new home-run, capping the newly-abandoned hot wire at both ends.

2. Place a 2-ckt breaker box at the load end of the existing home run, and install two 1p AFCI's there.

 

[stickboy1375]

I replaced a panel this weekend that had one 15 Amp MWBC feeding two bedrooms. My question is with the arc fault breaker that is required. I cant seperate the circuits onto two AFCI due to the one neutral and a two pole AFCI is not produced! How does the code account for this common wiring practice in older homes if it does at all. I initially placed both ungrounded conductors on one AFCI but nowI believe I have an overloading problem.

Either keep it the way you left it, or wait till 2-pole arc fault breakers are released... Thats the best you can do... Personally, installing AFCI's on a panel upgrade is not required (yet)... but a hell of an upsell! WHOO-HOO!!!!

 

[electricmanscott]

I replaced a panel this weekend that had one 15 Amp MWBC feeding two bedrooms. My question is with the arc fault breaker that is required. I cant seperate the circuits onto two AFCI due to the one neutral and a two pole AFCI is not produced! How does the code account for this common wiring practice in older homes if it does at all. I initially placed both ungrounded conductors on one AFCI but nowI believe I have an overloading problem.

The NEC does not require AFCI's to be installed in the job you describe.

 

[dgrey]

NEC 08 210.12 (B) states that that arc faults are to be used on all dwelling unit branch circuits supplying family rooms, dining rooms, living rooms, parlors, libraries, dens, sunrooms, rec rooms,closets, hallways or similar. So I take that to mean newly installed services, replacement panels or even when you simply add a new circuit it goes on an arc fault. Am I mistaken? I dont see any exceptions other than circuits in conduit or AC.

 

[Dennis Alwon]

NEC 08 210.12 (B) states that that arc faults are to be used on all dwelling unit branch circuits supplying family rooms, dining rooms, living rooms, parlors, libraries, dens, sunrooms, rec rooms,closets, hallways or similar. So I take that to mean newly installed services, replacement panels or even when you simply add a new circuit it goes on an arc fault. Am I mistaken? I dont see any exceptions other than circuits in conduit or AC.

Adding a circuit or a receptacle to a room is a very different animal than changing a service panel. It would be unfair for an inspector to require that.

With that same thinking, I would need to change all circuits to arc faults if I go into a house and add a circuits. If I add circuits to an existing home do I need to make the entire house code compliant to the 2008 code? I think not.

 

[dgrey]

Adding a circuit or circuits to a dwelling wouldn't mean changing all the breakers because the code is not retroactive but you would have to put the new circuits on an AFCI. Right? So with that in mind, installing a new panel or replacing a service would require you to put the proper circuits on AFCI because you are upgrading the system.