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#163236 - 05/04/07 02:26 PM 3 phase transformer
kyelectric Offline
Member

Registered: 08/30/05
Posts: 64
On a 75kva 3 phase transformer I use my Ugly's book to see that it is rated for 180 amps full load current. Looking at the allowable ampacities of conductors table I can see that using 75 C column and going to 180 amps that I can use 4/0 alum. or copper clad cable. When I inspected the transformer I found it to be wired with 4/0 paralled USE type cables. Was that over kill or why did they parallel the cables with 6 line conductors and 2 neutrals instead of using 3 line conductors and 1 neutral. I know it can't hurt to over size the wire (except cost and lug size in the panels). Thanks!

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#163237 - 05/04/07 02:29 PM Re: 3 phase transformer [Re: kyelectric]
codewarrior Offline
Member

Registered: 12/26/05
Posts: 17
Loc: Camden,New Jersey
They problably did that because of voltage drop to a long distance load.

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#163260 - 05/04/07 07:37 PM Re: 3 phase transformer [Re: codewarrior]
kyelectric Offline
Member

Registered: 08/30/05
Posts: 64
Codewarrior,
You are correct. I went back by there this afternoon and realized that the run is probably around 250 to 300 feet. So, they upsized to compensate for voltage drop. Thanks for the reply.

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#163263 - 05/04/07 07:49 PM Re: 3 phase transformer [Re: kyelectric]
codewarrior Offline
Member

Registered: 12/26/05
Posts: 17
Loc: Camden,New Jersey
Glad I could be of help

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