Cu vs. Al


Old 06-14-07, 12:42 PM
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Cu vs. Al

I am going to run an underground cable from my house panel to my barn (250') for lights and a receptacle. Would it be best to use 10-3/ground or equivalent aluminum for cost purposes. If so what size conductor in Al would I need? thanks
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Old 06-14-07, 12:48 PM
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At that distance with 10 gage wire you will not get much power. What were you planning for out there?

I would run aluminum and power a sub panel.
Old 06-14-07, 01:00 PM
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Cu vs. Al

I was planning on 3- 75 watt lights, and one 120 receptacle for light portable tools.
Old 06-14-07, 01:11 PM
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"I would run aluminum and power a subpanel"

Yeah, what he said. The wire savings would probably pay for a 60A subpanel.
Old 06-14-07, 01:42 PM
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I also agree. I would not limit yourself to a multi-wire circuit (two circuits).
You'll be sorry later when you get that 220v compressor you've always wanted.
Old 06-14-07, 02:20 PM
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You'll be sorry when you run 10 gauge CU and the voltage drop is so bad you can't light a 75w bulb.
Old 06-14-07, 02:27 PM
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You won't be able to find AL wire that small.
Old 06-14-07, 03:42 PM
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No, but larger aluminum cable will be cheaper anyway, which is he why he should consider the subpanel.
Old 06-15-07, 08:28 AM
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This is a good case for aluminum #2-2-2-4 underground mobile home feeder cable; it should be available at all the big box stores and supply houses. Normally, this cable is good for 100A, but over the 250' distance it shouldn't be used for more than 50A.

Given the distance, #10 copper is too small for even a 15A circuit. You would need to upsize to #8/3 UF for a 15A or 20A multiwire circuit.

#8/3 UF is about $2.49/ft. and 2-2-2-4 AL is about $2.60/ft. Three times the available power for about 10c more per foot.

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