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#177985 05/20/08 09:45 PM
Joined: Mar 2007
Posts: 1
johntum Offline OP
New Member
Hello all...
Ive got an issue here. Im upgading a residential service from 100A to 200A. in looking at the service a privious electrian has moved the older panel from inside (closet) to the exterior. he installed the 100A panel with most of the circiuts extended with 12/3NM. most of the house is now on multiwire circuits.The new panel will requier AFCI breakers for the bedrooms. these cannot be installed on shared neutral circiuts. The old location for the first panel is "around the corner" from the new panels. so pulling new extentions for these lines will involve a LOT of drywall/paint work.. should i run from this project?

john t

johntum #177986 05/20/08 10:05 PM
Joined: Aug 2001
Posts: 459
Does your jurisdiction require that the old circuit be brought up to Code when doing the service upgrade or when the circuit itself is modified?

Can the 12/3's be replaced with 12/2's?

I may not run from the job by you need to price appropriately and give a warning about the drywall work and the required patch and paint.

Jim M #178000 05/21/08 06:32 AM
Joined: Mar 2005
Posts: 1,213
Call your AHJ and ask them if they require it for the work you're doing. Even if they normally do, they may grant a waiver in this case, given the circumstances.

johntum #178004 05/21/08 07:07 AM
Joined: Dec 2001
Posts: 444
How about using a 2 pole AFCI breaker? In this situation, what harm would there be in AFCIing a non bedroom circuit?

Sandro #178007 05/21/08 10:06 AM
Joined: Jan 2005
Posts: 5,316
Cat Servant
Sandro, there seems to be an issue, as to whether there will ever be a two-pole combination type AFCI. I have seen a memo, purportedly from NEMA (note that I am still not convinced of it's authenticity), that essentially says "too bad" if the lack of two pole AFCI's eliminates the use of multi-wire branch circuits.

The 2008 NEC also introduces plenty of restrictions on the use of the "shared neutral." It's almost as if they want to discourage the practice.

On the bright side .... there is an opening for AFCI devices. While the code still calls for the run to the panel to be in a metal raceway, IMO device AFCI's are ideal for old work, such as you describe.

renosteinke #178014 05/21/08 12:33 PM
Joined: Jul 2004
Posts: 9,662
Likes: 4
John, the problem is, if you don't already have a metal wiring method, it will be as hard to put it in as it would be to just run 2 regular circuits and abandon the multiwire.

Greg Fretwell
renosteinke #178032 05/21/08 08:02 PM
Joined: Dec 2001
Posts: 444
Please forgive me if I am misunderstanding something here, but I have used 2 pole AFCI's many times with no issues. Is our canadian code different then the US code in respect to this matter?

Sandro #178033 05/21/08 08:18 PM
Joined: Jan 2005
Posts: 5,316
Cat Servant
Greg, you are correct ... and the attitude of the code panel towards the use of AFCI's in old work is but one of the many tangents to this thorny issue.

Sandro, I'm a bit puzzled myself; that's part of the reason I am not ready to accept that "memo" as genuine. At any rate = and I have to go by hearsay, lacking direct experience - the AFCI for this year is somehow different from the AFCI from last year. Hence, the name "combination AFCI."

ECN is one of the most popular internet electrical forums. The entire mess could be solved, if only one of our established members - and I know you're out there - would come out and say "I work for "X," we make combo AFCI's for use on multi-wire branch circuits, they are in the distribution pipeline, and you should have no trouble getting them."
So far, that statement has not been made.

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