Use of #3AWG Not Common

[kwired]

I don't do a lot of commercial work, so I wouldn't have a common use for #3

But 3 years ago I wired a restaurant that had 2 - 100 amp subpanels, and I got #3 from a supply house readily available.

In fact, I still had some of the scrap laying around, and used it on 2 residential subpanels in the last week or so.

You still need full 100 amp conductor (or at least 91 amps or more) for a 100 amp subpanel in a dwelling if it is not feeding an entire dwelling unit. If you chose to do this with copper do you try to get #3 or do you get #2? Same for #1 vs #2 if aluminum? With SER cable it may be more common to find 1/0 aluminum than #1 aluminum?

 

[James L]

You still need full 100 amp conductor (or at least 91 amps or more) for a 100 amp subpanel in a dwelling if it is not feeding an entire dwelling unit. If you chose to do this with copper do you try to get #3 or do you get #2? Same for #1 vs #2 if aluminum? With SER cable it may be more common to find 1/0 aluminum than #1 aluminum?

I don't run copper feeders in residential applications unless aluminum isn't allowed.

One municipality here used to not allow any aluminum at all, and we'd have to run all copper.

And I think you're right about #1 vs 1/0 AL SER

 

[tortuga]

I think it is about the same as 95mm2.

That's quite common in UK.

I believe the closest metric wire to 3 AWG is 25mm²

I can get 3AWG copper all day long here, and in all kinds of colors but 3 AWG aluminum has a high minimum order for me.

 

[kwired]

I've had times when utility guys ask what size your conductors are so they can grab connectors before going up to connect to their drop, and if you tell them #3 they act like that is not possible.