Single strand aluminum wire

Looked at this panel today - single strand AL wire for a 45-amp circuit which is labelled for the “A/C”. I normally see AL wire, but it is not single strand. This a Siemens panel in a house built in 2000. I was not expecting to find this…

…and, the AL gauge looks small for a 45 amp circuit, eh, Andy?

I wasn’t sure, but that was my initial impression. And a lot of grease on the connections…

Well, it is hard to tell from MI. But, it doesn’t look like at least 8 gauge:

I can only figure it may be AA-8000 series aluminum alloy (sometimes referred to as “new technology” aluminum wiring) as specified by industry standards such as the NEC.
However only for a 15 or 20 amp circuit, not that 45A breaker that Larry identified.
Also if it was the smaller size, then you run into that the Siemens breaker may not be designed for AL.


Check the data plate on the AC, it will tell you what you need.


Step #1?..

Thanks, Marcel. I missed that it was for the AC…my bad. :pensive:

Should have mentioned - data plate calls for 45… I cant remember ever seeing single strand aluminum for this before…

I have seen copper wire look like aluminum its called tinning only way to tell is to pull a wire from the breaker and look at the core I believe this is what you have here based on the year built.

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It is nice to see you on our forum again, Bill!..Enjoy! :smile:

Since the MCA is 26 amps you need #8 Al NM cable.

Does it have to be NM type?

No but I’m guessing that the cable in the OP is NM.

Oh okay, I thought it had to be NM in general. Thanks!

Sorry for the confusion. For NM cable the conductor ampacity is based on 60° C column in T310.15(B)(16) in the NEC. That lists #10 aluminum as 25 amps, since the MCA is 26 amps the aluminum conductor would need to be a minimum of #8 (35 amps @ 60° C) with a 45 amp Max OCPD. Further I don’t believe that they ever made solid #8 aluminum in a cable so one could assume that the conductor in the photo is smaller than #8.


Tinned copper would pre-date a house from 2000 by many years.