AFCIs on Split Phase Circuits

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  #1  
Old 01-02-13, 04:24 PM
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AFCIs on Split Phase Circuits

I would like to upgrade the bedroom 20 amp circuits to AFCI circuits. The problem is that all the 20 amp circuits are wired split phase, (I hope that is the correct term, wired using one neutral and two hots on opposite breaker positions). Am I out of luck or is there a solution out there for me?
 
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Old 01-02-13, 04:35 PM
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The correct term is a multi-wired branch circuit. Unless your brand of panel has a 2 pole AFCI breaker you are out of luck. IIRC there is only one brand of 2 pole AFCI available.
 
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Old 01-02-13, 04:45 PM
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I found them. It is a Cuttler Hammer panel. At $150 each, I think I will think about it. Thanks for the info.
 
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Old 01-02-13, 06:57 PM
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If I were you, I would wait a while. While I haven't heard of anything yet, I suspect there will be AFCI devices coming out in the near future.
 
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Old 01-02-13, 07:11 PM
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Thanks. I will wait a while and then take another look. I guess the multi-wired branch circuit idea was not too popular.
 
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Old 01-02-13, 08:02 PM
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AFCI receptacles are supposedly available but back-ordered -
Leviton - AFTR1-I, Arc Fault/Tamper Receptacles, Tamper Resistant, Wiring Devices - Platt Electric Supply
You would use two on a MWBC so it would still cost you $75. Code says they need to be first receptacle on circuit which can be challenging enough without it being a MWBC.
 
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Old 01-03-13, 04:08 PM
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I guess the multi-wired branch circuit idea was not too popular.
It is very popular, and used all the time. Just not as much in today's homes as the code is trying to make it more difficult to use them. There can be hazards when working with them which is why it is not a good idea to work on electrical circuits if you do not know what your are doing.

Code says they need to be first receptacle on circuit which can be challenging enough without it being a MWBC.
I do not have the 2011 code book in front of me, but I believe the current code requires a circuit, that is protected by an AFCI, is protected along it's entire length. This means that it can only be achieved by a breaker. IIRC there are some changes coming to allow the use of devices for existing installations in 2013.
 
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Old 01-03-13, 06:07 PM
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I believe the current code requires a circuit, that is protected by an AFCI, is protected along it's entire length.
Just working from memory here, but isn't there an exception to the entire length of the homerun being AFCI protected if it is in metallic conduit or metal clad cable?
 
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Old 01-03-13, 06:53 PM
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Yes, Exception #1 allows the use of RMC, IMC, EMT or steel armored AC to the first outlet. You can then install the AFCI at that outlet. Not sure why they don't accept steel armored MC cable. This is out of the 2008 Code.
 
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Old 01-04-13, 06:18 PM
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Right from the product flyer I found at the link above.

Exception 1: AFCI protection can be of the branch-circuit type located at the first outlet if the circuit conductors are installed in RMC, IMC, EMT or Type MC or steel armored Type AC cable meeting requirements of 250.118, and the AFCI device is contained in a metal outlet or junction box.
In addition, why would the homerun need to be in metallic conduit or flexible metallic cable since, the Leviton device protects both downstream of the AFCI device and UPSTREAM as well.

parallel and series arcing. Similar to GFCIs, AFCI receptacles provide feed-through protection and are able to detect
downstream arc-faults, both parallel and series, as well as upstream series arc-faults
I wonder what he 2014 version of the NEC will say?
 
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