I am trying to buy direct burial cable for a 240 volt service from my house to my polebarn. The barn is just for residential use & the biggest thing I plan to use is a 2 post lift which is 30 amp. I have a 200amp house service that I have a 100amp 2 pole breaker in that I will run the cable from. I plan to run direct buriable cable to a 100amp service panel in my polebarn. The distance totals 270ft from house to polebarn. I looked at copper wire (2 x 1/0 with a #6 neutral return) at nearly $1,900 I decided to look at aluminum instead. I used online calculators to find that I need 2/0 for aluminum but am not sure on the return neutral size needed? I found a cable bundled together 2/0, 2/0 & #1 called "converse underground secondary distrbution cable", is this OK or should I use separate cables? It totals only $403! I am aware that I need to use a dieletric paste to avoid corrosion, is there anything else I need to know about using aluminum instead of copper? Thanks.

You will need a 4 wire cable or system.

If you can find 4 wire #2/0 aluminum URD cable, it would suffice.

URD cable is rated for direct burial, will need conduit sleeve for physical protection where exposed out of ground.

Most aluminum wire nowadays does not need anit-oxidant compound uses at connections and terminals, but need to check the manufacturers datasheet. I use it anyway, if needed or not.

I am confused, why would I need 4 x 2/0? I was planning on 2 hot wires at 2/0, plus a neutral return at either #6 copper or whatever that equates to in aluminum. Plus a separate ground wire to the ground rod at the polebarn. Thanks

If ungrounded (live) conductors are increased to deal with voltage drop all conductors must be increased proportionally.

If you find the URD I mentioned, you will find that it is 2 -#2/0, plus probably a #1 for the neutral, and a #4 for the equipment ground. I am guessing the reduced wire sizes, but they are smaller than the live wires.

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Originally Posted by tkrussell

If ungrounded (live) conductors are increased to deal with voltage drop all conductors must be increased proportionally.

If you find the URD I mentioned, you will find that it is 2 -#2/0, plus probably a #1 for the neutral, and a #4 for the equipment ground. I am guessing the the reduced wire sizes, but they are smaller than the live wires.

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I was just planning to run a wire to a ground rod outside the polebarn. I already have a ground rod for the house panel. Are you saying I have to link the house ground to the polebarn also? Seems a long distance to run a ground wire? Thanks

3 wire feeders to separate structures are no longer allowed. You must run an equipment grounding conductor and drive a rod at the barn.

Quote:

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Originally Posted by tkrussell

3 wire feeders to separate structures are no longer allowed. You must run an equipment grounding conductor and drive a rod at the barn.

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Many thanks, I had seen this on a schematic but was not sure. I'll work out the correct sizes & price them out. Thanks for your help.