Will AFCI breaker protect Aluminium-wired branch circuit?


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Old 05-12-09, 06:56 PM
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Will AFCI breaker protect Aluminium-wired branch circuit?

I've been refinishing a room in my house, a 1961-1963ish A-frame that had a two-story addition put on around 1976. Some of the wiring in the A-frame section is black-clad aluminium 12-2 romex. In the process of opening up walls for remodelling, I've found aluminium wiring splices wrapped in electrical tape, and other fun. The aluminium branch circuits are terminated on the breakers with short copper pigtails.

I've been pulling and replacing the aluminium where I find it in the sections of the house I'm presently remodelling, but am concerned about hidden splices and/or other wiring problems in other sections, such as the two bedroom circuit on the second floor of the original construction.

Today, I moved said aluminium-wired branch circuit from a 15A breaker to a 15A AFCI breaker (which incidentally is indicating no faults). Will this be sufficient to mitigating AL wiring risk until I can remove the last runs of it and replace with 12-2 copper romex?
 
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Old 05-12-09, 07:32 PM
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I should think an AFCI would provide additional protection from a regular breaker provided it is a "Combination AFCI".
 
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Old 05-12-09, 07:58 PM
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Make sure the AFCI breaker is rated for aluminum wire. There should be a CU/Al mark on it someplace.
 
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Old 05-12-09, 08:13 PM
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Technically speaking the AFCI breaker is not an approved remedy for aluminum wire, but in my opinion it is probably the best thing you can do short of completely replacing the wire.

Make sure you get the newer combination series + parallel arc fault breakers. I believe these are sold under the "FireGuard" (or something like that) brand for all Eaton / Cutler / Bryant brands. The breakers which have series arc fault protection should have a trip threshold of 5A instead of the parallel threshold of something like 70A.

These are different than combination AFCI/GFCI class A breakers. Unfortunately the terms are somewhat confusing. Which make and model of breaker panel do you have? One of us may be able to look up the correct part numbers to help you get the right breakers.
 
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Old 05-12-09, 08:43 PM
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Originally Posted by ibpooks View Post
Make sure you get the newer combination series + parallel arc fault breakers. I believe these are sold under the "FireGuard" (or something like that) brand for all Eaton / Cutler / Bryant brands. The breakers which have series arc fault protection should have a trip threshold of 5A instead of the parallel threshold of something like 70A.

These are different than combination AFCI/GFCI class A breakers. Unfortunately the terms are somewhat confusing. Which make and model of breaker panel do you have? One of us may be able to look up the correct part numbers to help you get the right breakers.
I have an ITE-branded load center, which I believe to be equivalent to Siemens. The AFCI breaker I dropped in today was a Siemens QF115P 15A single-pole Class-A/5ma AFCI breaker, but I'm not sure about FireGuard equivalency...

Rather than connecting the aluminium branch feeder directly to the new breaker, I transplanted its copper pigtail from the older breaker. I'm not sure if this is here nor there, but the load center is accessed in a rainproof enclosure on the exterior of the home.
 
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Old 05-13-09, 08:45 AM
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The AFCI breaker I dropped in today was a Siemens QF115P 15A single-pole Class-A/5ma AFCI breaker
I'm not familiar with that part number with the "P" on the end. Without the "P", it's a GFCI breaker; and the 5mA rating also implies it's a GFCI breaker. It sounds like you may have actually gotten a GFCI breaker, not an AFCI breaker.

The ideal breakers you want for the ITE panel are "Siemens Combination Type AFCI" part numbers Q115AFC (15A) and Q120AFC (20A).

Note that they also sell a Q115AF, but this is a different breaker which is not exactly what you want.

Rather than connecting the aluminium branch feeder directly to the new breaker, I transplanted its copper pigtail from the older breaker.
Any breakers in the Q series can take the aluminum wire directly to the breaker terminal. In fact, that's probably the best thing to do.
 
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Old 05-13-09, 09:29 AM
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Siemens QF115P is indeed a GFCI...sold at Lowes and numerous other places as such.
 
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Old 05-13-09, 04:05 PM
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Originally Posted by Gunguy45 View Post
Siemens QF115P is indeed a GFCI...sold at Lowes and numerous other places as such.
Whoops, my bad. Well, this is what I get for trying to go to the home depot site and ID what I bought by looking for it. So, I've gone back to my kitchen trash and pulled out the packaging for the breaker.

It's actually a Siemens Q115AFCP "combination type arc-fault circuit interrupter." Sorry to those who checked the wrong model out, my bad.
 
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Old 05-13-09, 07:10 PM
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Looks like you're good to go.
 
 

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