Power mains question: wire gauge

Discussion in 'Misc Electronics' started by DaveC, Dec 28, 2012.

  1. DaveC

    DaveC Guest

    Air compressor 1/2 hp motor rated 220v (2-wire, not 3-phase) @ 15A. Distance
    from load panel ~100 ft (as the conduit runs).

    15A can be handled by 14 gauge, but I'd normally go with 12 gauge due to
    start current.

    With such a distance, is it recommend to up-scale the wire to 10 ga?

    DaveC, Dec 28, 2012
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  2. DaveC

    SoothSayer Guest

    Cant hurt. It would definitely help, in fact. multiple #14s to make
    each #10 would work better, keeping each segment electrically separated
    except at the nodes, giving a sort of Litz effect. At that gauge, you
    can get SPC too (Silver Plated Copper), reducing ohms per foot without
    increasing gauge above #10.

    And you want a #12 return run for ground fault carriage too.
    A single piece would pop a breaker.
    SoothSayer, Dec 28, 2012
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  3. DaveC

    Phil Allison Guest


    ** Giant HUH ??

    Such a motor normally draws around 3 amps.

    .... Phil
    Phil Allison, Dec 29, 2012
  4. DaveC


    considered what the skin deepth at 60Hz is?....

    , Dec 29, 2012
  5. DaveC

    Bill Guest

    There is s thing called "voltage drop". Voltage will drop in a wire
    running a long distance, sometimes so much, the device at the end will
    not operate!

    The amount of voltage drop depends on the voltage, the type of metal
    used for the wire (copper / aluminum), the wire size, and the load in
    amperage at the end of that wire.

    The internet has made this easy for you. Just search google.com for the

    Voltage Drop Calculator
    Bill, Dec 29, 2012
  6. DaveC

    DaveC Guest

    Until the motor or compressor is replaced with a larger unit. Then
    That's a good idea. I'll talk it over with the owner.

    But for now I want to settle on what size conductor to use if it's just to
    supply this one compressor.

    DaveC, Dec 29, 2012
  7. DaveC


    If it's 1/2HP, now, it's unlikely to grow to >5HP.
    Run several #12s, instead, when needed. It's cheaper.
    , Dec 29, 2012
  8. DaveC

    notme Guest

    Run several #12s, instead, when needed. It's cheaper.

    Pull additional #12s in the future? I've had bad experience pulling
    additional conductors in a conduit with existing conductors.

    If I misunderstand your statement, please try again. ;-)

    notme, Dec 29, 2012
  9. DaveC

    MrTallyman Guest

    No. A bundle of a few 12s will make a nice oversized #10.
    The finished 'wire' will be stronger and more flexible too.

    Of course, the return has to match. So you pull all 7 at once.

    Two sets of 3 #12s and one #12 fault return. Seven wires.
    MrTallyman, Dec 29, 2012
  10. DaveC


    , Dec 29, 2012
  11. DaveC


    I've seen a *lot* of 1/2HP motors used for power tools that can be
    wired either way.
    Rather irrelevant.
    I always do it the right way. The "right way" depends on the
    situation. I guess the "right side" is universal, though, but it's
    also right.
    It's a *lot* cheaper. #6 is a PITA to work with. No thanks!
    Now you're throwing in random costs.
    , Dec 29, 2012
  12. DaveC


    OK, 300K.
    , Dec 29, 2012
  13. DaveC

    Tom Biasi Guest

    How about run what you need now with a pull string included?
    Tom Biasi, Dec 30, 2012
  14. DaveC


    Sure. Most small fractional horse induction motors can be.
    , Dec 30, 2012
  15. DaveC


    I think we have a winner!
    , Dec 30, 2012
  16. DaveC


    Hey, you never know how big of a compressor you might need.
    , Dec 30, 2012
  17. DaveC

    rickman Guest

    100 feet of AWG 6 will set you back some C-notes. That's an expensive
    investment if you don't need it.

    rickman, Dec 30, 2012
  18. DaveC

    SoothSayer Guest

    What utter idiot suggested #6?
    SoothSayer, Dec 30, 2012
  19. It's also a sweaty PITA to pull.. ( I ran some to a manly (for single
    phase) compressor and kiln).

    Best regards,
    Spehro Pefhany
    Spehro Pefhany, Dec 30, 2012
  20. DaveC

    Jasen Betts Guest

    a larger compresser is likely to have a soft start where the pump
    compression is releived come on until it's up to speed.
    Jasen Betts, Dec 30, 2012
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