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DIYALLTHETIME 03-04-2009 12:41 PM

Copper wire sizing underground 185ft run 200A service
I live in Northern California and I want to install an underground service to a new construction, distance from power drop panel to sub panel is 185feet.
I have been told that for a 200Amp service the wire size will have to be 4/O Copper.
My question is: Can I use a smaller size Copper wire than 4/0 for the Ground conducter. Or do I have to run all three at 4/0?
It will be a standard 3 wire install through 3 inch Conduit.
Many thanks for any advice

craneservice 03-04-2009 12:58 PM

The 3 feeders must be 4/0 the ground the 4th wire should be #4

DIYALLTHETIME 03-04-2009 01:26 PM

Many thanks for such a quick reply
Do I have to run 4/0 copper as two hot legs, and one neutral, plus a ground leg from the 200A panel ( 4 wires total running to the home in 3" conduit) or can I run two 4/0 legs and one ground to the home if so what size ground and how would you then install this in the panel.
I have seen this in the past but I'm now a little unsure from your reply

Will I get a 240V supply at the house with a 3 wire pull, 2 hot legs 4/0 one ground 2/0? which can be used as a neutral? what are the complications of 3 wire or benefits of 4 wire install?

It will be a standard 240V single phase install through 3 inch buried Conduit.

micromind 03-04-2009 07:35 PM

The minimum code size for a neutral is pretty small.

If it were me, I'd run the two hots as 4/0, and a 2/0 or maybe 3/0 for the neutral. #4 for the ground will be OK.


jamiedolan 03-04-2009 07:40 PM


Originally Posted by craneservice (Post 240125)
The 3 feeders must be 4/0

Based on what?

Stubbie 03-04-2009 08:22 PM

I think you mean 4/0 aluminum not copper...:)

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