I am building a detached garage and have installed a 125 amp panel. I plan to install the service disconnect by the meter base. What size wire do I run from the service disconnect to the panel in the garage. The distance is about 125 feet. I have been told that I could use 2-2-4-6 aluminum, but according to NEC Table 310.16 I would need either 1/0 for 90 degrees C or 2/0 for 75 degrees C. I don't have Table 310.15.B.6, which is what I was told the 2-2-4-6 was selected from.

I'm just going to say this.

1. You are not allowed to use T. 310.15
2. Equipment rated over 100A must have the conductors sized no smaller than the 75 degree column of T. 310.16
3. Your 4th conductor is Alum??
4. What do you think?

Then I'll just say this.

We use 2-2-2-4 or 2-2-4-6 URD cable for 100A remote sub-panels. Yes, all four conductors are AL.
This is the typical installation around here.

Not all areas are alike. Many DO allow this installation, which IMO makes complete sense.

If your area does not allow this, then simply use a 90A breaker in the feeder disconnect.

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Originally Posted by stanfortyman

Then I'll just say this.

We use 2-2-2-4 or 2-2-4-6 URD cable for 100A remote sub-panels. Yes, all four conductors are AL.
This is the typical installation around here.

Not all areas are alike. Many DO allow this installation, which IMO makes complete sense.

If your area does not allow this, then simply use a 90A breaker in the feeder disconnect.

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Interesting:D

Sounds good too me, if the URD is complaint--having the xhhw or rhh rating. Or even better, use THHN/THWN copper (too expensive, then use xhhw [alum] ). Yet, if your URD (Which is not recognized) is rated for both (XHHW or RHH) then you are fine... I guess this is what I meant!? ;)

;) :cool: :eek: :) <----did I over do it!

Quote:

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Sounds good too me, if the URD is complaint--having the xhhw or rhh rating. Or even better, use THHN/THWN copper (too expensive, then use xhhw [alum] ). Yet, if your URD (Which is not recognized) is rated for both (XHHW or RHH) then you are fine... I guess this is what I meant!?

<----did I over do it!

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I guess not! :)

I didn't even realize that was a question. Duh!

Yes, I know URD is not recognized by some jurisdictions, but it is approved and used almost exclusively around here for underground services and sub-feeds.

Thanks for the answers. I decided to go with mobile home feeder that is 2-2-2-4, type USE-2.