2 AFCI questions

**Jim Robinson** · 11-15-2008, 09:50 AM

If a service panel is replaced in an older house, can the original circuits that were wired with 12-3 use an AFCI breaker, or will the shared neutral cause it not to function properly?

Would the new NEC require existing GFCI circuits such as a hot tub to also be protected by an AFCI breaker?

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Ted Menelly · 11-15-2008, 11:19 AM

Originally Posted by Jim Robinson

If a service panel is replaced in an older house, can the original circuits that were wired with 12-3 use an AFCI breaker, or will the shared neutral cause it not to function properly?

Would the new NEC require existing GFCI circuits such as a hot tub to also be protected by an AFCI breaker?

If an outlet is not protected by GFCI it will require AFCI. Besides the hot tub or master Jacuzzi has to have GFCI not arc fault protection same as any other wet area in the home (kitchen, bath, exterior,garage etc.

Are you saying the older home is wired with 12-3 and not 12-2 with ground. I have run into this up north but not in the south or I just don't run into it down here.

John Steinke · 11-15-2008, 04:35 PM

This is a subject you must take up with the AHJ.

Many places have decided not to require AFCI's for panel replacements / service changes.

The latest version of the AFCI, the 'combination type,' is not available in a two ple version. While AFCI devices are permitted, I don't think they're available either.

You can be sure that the appropriate code committee is currently deluged with proposals on this topic.

**Jerry Peck** · 11-15-2008, 04:56 PM

Originally Posted by Jim Robinson

If a service panel is replaced in an older house, can the original circuits that were wired with 12-3 use an AFCI breaker,

Originally Posted by John Steinke

This is a subject you must take up with the AHJ.

Huh?

Even the following ...

Would the new NEC require existing GFCI circuits such as a hot tub to also be protected by an AFCI breaker?

... does not need to be taken up with the AHJ, it is a simple NEC code question.

**Jim Robinson** · 11-15-2008, 05:38 PM

Yeah, it's 12-3 so it's two breakers sharing a neutral wire. In fact, it's 12-3 without a ground, since it was built in about 1951. Got the answer on the GFCI, which makes sense. I have been told that the AFCI breaker will not work with a 12-3 shared neutral, much like the GFCI breaker will not. I was just looking for some confirmation.

BTW, this is for my house. I'm about to replace my service panel, and I'm trying to figure out exactly what I might be in for with my local AHJ.

**Jerry Peck** · 11-15-2008, 06:18 PM

Originally Posted by Jim Robinson

Got the answer on the GFCI, which makes sense. I have been told that the AFCI breaker will not work with a 12-3 shared neutral, much like the GFCI breaker will not.

A GFCI breaker rated for 120 volt / 240 volt use (but not one just rated for 240 volt use) WILL protect a multi-wire circuit (the 12-3 circuit you are describing). I got that straight from Siemens - they make 120 volt / 240 volt rated GFCI breakers.

Regarding the AFCI on multi-wire circuits, the best answer I have is "I believe they will work on multi-wire circuits", this based on understanding how they work (but you may need to get a 120 volt / 240 volt rated AFCI breaker to avoid any potential interference cross-talk because of the shared neutral ... maybe not - just not 100% sure.

**Gunnar Alquist** · 11-15-2008, 07:10 PM

An electrical contractor that I recently spoke with told me that that AFCIs will not work with multi-wire circuits. I have not confirmed this.

**Jerry Peck** · 11-15-2008, 07:20 PM

Originally Posted by Gunnar Alquist

An electrical contractor that I recently spoke with told me that that AFCIs will not work with multi-wire circuits. I have not confirmed this.

I just sent an e-mail off to the engineer at Siemens, who answered my GFCI on multi-wire circuits question, asking if AFCI breakers will work on multi-wire circuits.

I hope to hear back from him on Monday or Tuesday.

**Jerry Peck** · 11-16-2008, 08:14 PM

Originally Posted by Jerry Peck

I just sent an e-mail off to the engineer at Siemens, who answered my GFCI on multi-wire circuits question, asking if AFCI breakers will work on multi-wire circuits.

I hope to hear back from him on Monday or Tuesday.

This is the answer I received back this evening:

Jerry,
Only a two pole AFCI can be used on multi-wire branch circuits since these AFCI devices also include detection for current imbalance. It is this current imbalance that is the real issue. Crosstalk is not a concern. At this time, we only offer the older Branch/Feeder AFCI in a two pole version. We have not yet released a two pole Combination Type AFCI.

John Steinke · 11-24-2008, 09:58 PM

As to whether a code 'requires' something is a question that can only be resolved by the AHJ.

Does a particular code require somethnig? Only if you deny that other codes may overule or limit the scope of the code. Regarding AFCI's and service upgrades, this is one area of great debate, and wide local variance.

Even were one to stipulate that the NEC required AFCI's .... with a multi-wire branch circuit, there is no product made that can be used. Earlier AFCI's were not the "combination type" now required by the NEC, and there are no combination-type AFCI's that can be used on multi-wire branch circuits.

Can a code require you to use something that does not exist? Lots of luck enforcing that one!

Carry it further ... would a service change require, by extension, the complete rewire of a house that had multi-wire branch circuits? Such a requirement is clearly beyond the scope of codes, in effect requiring the retroactive enforcement of today's rules on yesterdays' work. Such is simply unconstitutional.

But for safety .... Please! We have these limits upon authority, simply because tyranny and slavery are inherently unsafe. If one cannot accept limitatiojns to their authority, they have no business in any position of authority.

Jeff Remas · 11-25-2008, 02:07 AM

Multi-Wire circuits can only work with both AFCI and GFCI if you install a double pole GFCI or AFCI breaker. They make double pole GFCI breakers but I have never seen a double pole AFCI.

**Jerry Peck** · 11-25-2008, 03:20 PM

Originally Posted by John Steinke

As to whether a code 'requires' something is a question that can only be resolved by the AHJ.

Incorrectly stated, John.

A code requires it if it is written in the code, whether or not the AHJ enforces it. The AHJ does not change the code as written, only their local enforcement of it.

In many areas, the AHJ may adopt amendments to the code, in which case they are enforcing the code as it is written *and the amendments to the code*.

Even were one to stipulate that the NEC required AFCI's .... with a multi-wire branch circuit, there is no product made that can be used.

There is product which can be used for AFCI protection of multi-wire branch circuits.

The correct way to say what you are trying to say (or at least what I think you are trying to say) is that there are no AFCI breakers currently which will fulfill the 2008 AFCI requirements for multi-wire branch circuits.

Can a code require you to use something that does not exist? Lots of luck enforcing that one!

No, but it CAN require you to not use a new multi-wire branch circuit on circuits which require the new combination AFCIs. Simply because that it the only way you will meet the AFCI requirements.

You need to not think to tight against yourself, John, you need to expand your thinking in what is actually being addressed, and how to meet it.

**Jerry Peck** · 11-25-2008, 03:24 PM

Originally Posted by Jeff Remas

Multi-Wire circuits can only work with both AFCI and GFCI if you install a double pole GFCI or AFCI breaker. They make double pole GFCI breakers but I have never seen a double pole AFCI.

Jeff,

A slight correction to the above.

The GFCI and AFCI double pole breakers must also be rated 120 volt / 240 volt, not 240 volt only. The 120 volt / 240 volt double pole GFCI and AFCI breakers will work on multi-wire circuits.

Siemens makes a double pole AFCI breaker which is rated 120 volt / 240 volt, but it is the older type, not the "combination" type - not as yet (not as of last week).