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#94144 - 07/07/05 08:24 PM conduit fill
MI Sparky Offline

Registered: 07/06/05
Posts: 14
Loc: Fenton, MI
since I dont have a code book handy, and I tried an online fill calculater...lets pose this question: 3 #6(Thhn/Thwn) and 1 #8 (thhn/thwn) in one conduit (NMRC) IE PVC, underground, unless I have missed something, using area per conductor, I should be able to use 3/4. I dont feel right using 3/4, I want to use 1"
Whats your thoughts?

This is for a hot tub rated at 50 amps, about a 150'-200' run
I thought that was off!!!!

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#94145 - 07/07/05 08:38 PM Re: conduit fill
Tech-Home Offline

Registered: 05/15/05
Posts: 16
Loc: Burnsville, MN, USA
I use 1 inch regardless of what I can get by with. Easier pull, less strain on conductors.

#94146 - 07/08/05 12:38 PM Re: conduit fill
George Little Offline

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
MI sparky- since you gave me a left handed compliment I looked up the numbers for you:

Your total wire area in sq. inches is .1887 and the 40% fill limit would allow you to use ¾" Schedule 40 RNMC (.203) but not Schedule 80 (.164). As Tech Home said I'd probably run 1 inch because it's easier especially on that length of run. Wish you well in your career move.
George Little


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