1. ## afci ?

This is more a ?
I have a new home " " now this home has 3 bedrooms ,2 bathrooms 1 kitchen and so on.
2 bedrooms have a 12/3 as a line (to different circuits sharing the same neutral) (phase "a"=n of out lets --- phase "b"=n of out lets ) (phase "a" bedroom1--- phase "b" bedroom2)

Now the question is: Can we install on the circuit panel a AFCI type of breakers for this 2 particular branch circuits?

2. ## Re: afci ?

Originally Posted by bb_becker
Now the question is: Can we install on the circuit panel a AFCI type of breakers for this 2 particular branch circuits?
Not only can you, but you are also required to.

AFCIs are different than GFCIs, and the answer would be different for GFCIs.

Question: Why? As in 'Why do you want to use 12-3 instead of two separate 12-2 circuits?'

There is very little cost savings and it can have a negative effect later if someone tries to move circuits around in the panel.

I really see no distinct advantage of running one 12-3 multi-wire circuit over two 12-2 circuits.

3. ## Re: afci ?

The answer to using 12/3 (comman netrual) on AFCI breakers is this will cause nuisance triping. The instructions for the AFCI will tell you this. Go to a electical or building supply and read the instulation instructions.

Jim Farmer
Out here in God's country.

4. ## Re: afci ?

Originally Posted by Jerry Peck
I really see no distinct advantage of running one 12-3 multi-wire circuit over two 12-2 circuits.
Can I get an amen from anybody on this one? ................AMEN!

5. ## Re: afci ?

This arc-fault detection device is not
designed or intended for use on circuits
in which the neutral conductor is shared
with other circuits. The circuit breaker
will nuisance trip in “shared neutral”

circuits.

This is from the Square D homeline instructions from their website.
It appears Mr. Farmer is correct for at least this brand.

6. ## Re: afci ?

Thank you Jim.

Learned something new (as I always try to every day).

Know what that means?

It means *NO MORE MULTI-WIRE CIRCUITS* for bedrooms. Cool!

Because, after all, the bedroom circuits *are required* to have AFCI protection. Not 'unless the circuits are multi-wire', just as plain and simple 'required to have'.

I like it.

7. ## Re: afci ?

don't forget two pole afci's

Last edited by paul hardy; 06-02-2008 at 06:54 PM. Reason: add attachment

8. ## Re: afci ?

Originally Posted by Jerry Peck
It means *NO MORE MULTI-WIRE CIRCUITS* for bedrooms. Cool!

Because, after all, the bedroom circuits *are required* to have AFCI protection. Not 'unless the circuits are multi-wire', just as plain and simple 'required to have'.
Originally Posted by paul hardy
don't forget two pole afci's

DANG!

That means multi-wire circuits to bedrooms can be AFCI protected.

9. ## Re: afci ?

When is an AFCI not a code-compliant AFCI?

The latest version of the NEC specifies "combination" type AFCI's. I am given to understand - times change, and I could be / maybe will be wrong - that there are no two-pole combination AFCI's made.

The two-pole AFCI's I've seen up to now were not the "combination" type.

I've even seen something circulated on the internet, purporting to be a NEMA statement, to the effect of "too bad" if the lack of two-pole combo AFCI's means no more shared neutrals.

Just what we need - more confusion, more uncertainty.

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