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  1. #1
    Join Date
    Nov 2011
    Location
    Sherman, TX
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    INSTALLING NEW AIR COMPRESSOR

    I'm upgrading my compressor to a new Campbell Hausfeld 7.5 HP 3 Phase pump and motor and I'm about 6 feet away from my breaker box. The manufacturer recommends a minimum of a 40 amp breaker for this setup. What gauge wire should I use for this short run? If it's relevant, I was previously running a Quincy pump for 30 years with a 5 HP motor on a 30 amp breaker with only 12 gauge wire with no overheating problems or blown breakers.

    Thanks in advance for your help.

    Doug

  2. #2
    Join Date
    Feb 2005
    Location
    In a van by the river
    Posts
    624
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    I'd use 8 gauge personally. I don't have the NEC book in front of me but 10 gauge may be sufficient. I'd still use 8 though.
    ## + years in the field never made you a know-it-all This industry is far more diverse than you are

  3. #3
    Join Date
    Feb 2013
    Location
    Phoenix, AZ
    Posts
    184
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    The good book says 8AWG copper.

    Your 30A installation, while it may have worked fine, was technically illegal.

  4. #4
    Join Date
    Nov 2011
    Location
    Sherman, TX
    Posts
    8
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    Thanks to both of you. I will go with 8 AWG. I'm not surprised about the previous wiring. My late father-in-law, a self professed electrician, lead me astray many times I have found out over the years and I am correcting them as I find them.

  5. #5
    Join Date
    Oct 2008
    Location
    In a kitchen with my head stuck in an oven
    Posts
    1,166
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    I'm being nosey, but since you said three phase, then you're replacing this compressor in a commercial building?

  6. #6
    Join Date
    Nov 2011
    Location
    Sherman, TX
    Posts
    8
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    Quote Originally Posted by ECtofix View Post
    I'm being nosey, but since you said three phase, then you're replacing this compressor in a commercial building?
    My mistake, I should have specified single phase at the beginning of the post. My apologies.

    Doug

  7. #7
    Join Date
    Aug 2009
    Location
    Maine
    Posts
    6,533
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    Make sure you use copper wire

  8. #8
    Join Date
    Jun 2013
    Posts
    67
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    Be sure to include an earth ground ( green or bare ) copper wire . # 10 is legal for the ground on a 40 amp circuit .

    God bless
    Wyr

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