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?

    Thanks.
     
    DaveC, Dec 28, 2012
    #1
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  2. DaveC

    SoothSayer Guest

    On Fri, 28 Dec 2012 15:41:08 -0800, DaveC <> wrote:

    >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?
    >
    >Thanks.



    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
    #2
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  3. DaveC

    Phil Allison Guest

    "DaveC"

    > Air compressor 1/2 hp motor rated 220v (2-wire, not 3-phase) @ 15A.



    ** Giant HUH ??

    Such a motor normally draws around 3 amps.




    .... Phil
     
    Phil Allison, Dec 29, 2012
    #3
  4. DaveC

    Guest

    On Dec 29, 12:48 am, SoothSayer <> wrote:
    > On Fri, 28 Dec 2012 15:41:08 -0800, DaveC <> wrote:
    > >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?

    >
    > >Thanks.

    >
    >   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.


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

    -Lasse
     
    , Dec 29, 2012
    #4
  5. DaveC

    Bill Guest

    In article <-september.org>,
    says...
    >
    > 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?
    >



    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
    words...

    Voltage Drop Calculator
     
    Bill, Dec 29, 2012
    #5
  6. DaveC

    DaveC Guest

    > Until the motor or compressor is replaced with a larger unit. Then
    > all bets are off. It's cheaper to do it right the first time. You
    > could even put a small breaker box by the compressor & run AWG 6 to it,
    > to power other tools, as needed without starting from scratch.


    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.

    Thanks.
     
    DaveC, Dec 29, 2012
    #6
  7. DaveC

    Guest

    On Sat, 29 Dec 2012 14:57:19 -0500, "Michael A. Terrell"
    <> wrote:

    >
    >John Larkin wrote:
    >>
    >> We're basically doing the same calculation, demonstrating that #12 (or
    >> 14) is plenty good enough.

    >
    >
    > Until the motor or compressor is replaced with a larger unit. Then
    >all bets are off. It's cheaper to do it right the first time.


    If it's 1/2HP, now, it's unlikely to grow to >5HP.

    >You
    >could even put a small breaker box by the compressor & run AWG 6 to it,
    >to power other tools, as needed without starting from scratch.


    Run several #12s, instead, when needed. It's cheaper.
     
    , Dec 29, 2012
    #7
  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. ;-)

    Thanks.
     
    notme, Dec 29, 2012
    #8
  9. DaveC

    MrTallyman Guest

    On Sat, 29 Dec 2012 13:04:27 -0800, notme <> wrote:

    >> 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. ;-)
    >
    >Thanks.



    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
    #9
  10. DaveC

    Guest

    On Sat, 29 Dec 2012 13:04:27 -0800, notme <> wrote:

    >> 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.


    Conduit?

    >If I misunderstand your statement, please try again. ;-)
     
    , Dec 29, 2012
    #10
  11. DaveC

    Guest

    On Sat, 29 Dec 2012 16:49:01 -0500, "Michael A. Terrell"
    <> wrote:

    >
    > wrote:
    >>
    >> On Sat, 29 Dec 2012 14:57:19 -0500, "Michael A. Terrell"
    >> ?? wrote:
    >>
    >> ?
    >> ?John Larkin wrote:
    >> ??
    >> ?? We're basically doing the same calculation, demonstrating that #12 (or
    >> ?? 14) is plenty good enough.
    >> ?
    >> ?
    >> ? Until the motor or compressor is replaced with a larger unit. Then
    >> ?all bets are off. It's cheaper to do it right the first time.
    >>
    >> If it's 1/2HP, now, it's unlikely to grow to ?5HP.

    >
    >
    > I've never seen a 240 volt compressor it a 1/2 HP motor 2 HP is
    >common, and go on up as the capacity increases.


    I've seen a *lot* of 1/2HP motors used for power tools that can be
    wired either way.

    >A local business
    >recently switched from multiple 2 HP 240 VAC 60 gallon compressors to a
    >pair of 480 VAC three phase units with 120 gallon tanks that are set upi
    >to run their entire production line from one unit. It was the old EDCO
    >factory that Emerson closed a few years ago..


    Rather irrelevant.
    >
    >> ?You
    >> ?could even put a small breaker box by the compressor ? run AWG 6 to it,
    >> ?to power other tools, as needed without starting from scratch.
    >>
    >> Run several #12s, instead, when needed. It's cheaper.

    >
    >
    > Cheaper? When did yo go over to the 'Do it any way but right' side?


    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 not cheaper when the extra labor and increased material costs
    >are added for doing the job more than once. If you didn't size the
    >conduit for more wire, you'll have to rip it all out & start over.


    It's a *lot* cheaper. #6 is a PITA to work with. No thanks!

    > Then there's the cost of a bribe to get the inspector to look the
    >other way.


    Now you're throwing in random costs.
     
    , Dec 29, 2012
    #11
  12. DaveC

    Guest

    On Sat, 29 Dec 2012 18:18:22 -0500, "Michael A. Terrell"
    <> wrote:

    >
    >John Larkin wrote:
    >>
    >> On Sat, 29 Dec 2012 14:57:19 -0500, "Michael A. Terrell"
    >> ?? wrote:
    >>
    >> ?
    >> ?John Larkin wrote:
    >> ??
    >> ?? We're basically doing the same calculation, demonstrating that #12 (or
    >> ?? 14) is plenty good enough.
    >> ?
    >> ?
    >> ? Until the motor or compressor is replaced with a larger unit. Then
    >> ?all bets are off. It's cheaper to do it right the first time. You
    >> ?could even put a small breaker box by the compressor ? run AWG 6 to it,
    >> ?to power other tools, as needed without starting from scratch.
    >>
    >> Well, then why stop at #6? Run 3KV and a distribution transformer. You
    >> never know.

    >
    >
    > Who uses 3KV?


    OK, 300K.
     
    , Dec 29, 2012
    #12
  13. DaveC

    Tom Biasi Guest

    On 12/29/2012 6:47 PM, wrote:
    > On Sat, 29 Dec 2012 18:18:22 -0500, "Michael A. Terrell"
    > <> wrote:
    >
    >>
    >> John Larkin wrote:
    >>>
    >>> On Sat, 29 Dec 2012 14:57:19 -0500, "Michael A. Terrell"
    >>> ?? wrote:
    >>>
    >>> ?
    >>> ?John Larkin wrote:
    >>> ??
    >>> ?? We're basically doing the same calculation, demonstrating that #12 (or
    >>> ?? 14) is plenty good enough.
    >>> ?
    >>> ?
    >>> ? Until the motor or compressor is replaced with a larger unit. Then
    >>> ?all bets are off. It's cheaper to do it right the first time. You
    >>> ?could even put a small breaker box by the compressor ? run AWG 6 to it,
    >>> ?to power other tools, as needed without starting from scratch.
    >>>
    >>> Well, then why stop at #6? Run 3KV and a distribution transformer. You
    >>> never know.

    >>
    >>
    >> Who uses 3KV?

    >
    > OK, 300K.
    >

    How about run what you need now with a pull string included?
     
    Tom Biasi, Dec 30, 2012
    #13
  14. DaveC

    Guest

    On Sat, 29 Dec 2012 20:52:31 -0500, "Michael A. Terrell"
    <> wrote:

    >
    > wrote:
    >>
    >> I've seen a *lot* of 1/2HP motors used for power tools that can be
    >> wired either way.

    >
    >
    > On an air compressor?


    Sure. Most small fractional horse induction motors can be.
     
    , Dec 30, 2012
    #14
  15. DaveC

    Guest

    On Sat, 29 Dec 2012 19:53:40 -0500, Tom Biasi <>
    wrote:

    >On 12/29/2012 6:47 PM, wrote:
    >> On Sat, 29 Dec 2012 18:18:22 -0500, "Michael A. Terrell"
    >> <> wrote:
    >>
    >>>
    >>> John Larkin wrote:
    >>>>
    >>>> On Sat, 29 Dec 2012 14:57:19 -0500, "Michael A. Terrell"
    >>>> ?? wrote:
    >>>>
    >>>> ?
    >>>> ?John Larkin wrote:
    >>>> ??
    >>>> ?? We're basically doing the same calculation, demonstrating that #12 (or
    >>>> ?? 14) is plenty good enough.
    >>>> ?
    >>>> ?
    >>>> ? Until the motor or compressor is replaced with a larger unit. Then
    >>>> ?all bets are off. It's cheaper to do it right the first time. You
    >>>> ?could even put a small breaker box by the compressor ? run AWG 6 to it,
    >>>> ?to power other tools, as needed without starting from scratch.
    >>>>
    >>>> Well, then why stop at #6? Run 3KV and a distribution transformer. You
    >>>> never know.
    >>>
    >>>
    >>> Who uses 3KV?

    >>
    >> OK, 300K.
    >>

    >How about run what you need now with a pull string included?


    I think we have a winner!
     
    , Dec 30, 2012
    #15
  16. DaveC

    Guest

    On Sat, 29 Dec 2012 20:51:35 -0500, "Michael A. Terrell"
    <> wrote:

    >
    > wrote:
    >>
    >> On Sat, 29 Dec 2012 18:18:22 -0500, "Michael A. Terrell"
    >> ?? wrote:
    >>
    >> ?
    >> ?John Larkin wrote:
    >> ??
    >> ?? On Sat, 29 Dec 2012 14:57:19 -0500, "Michael A. Terrell"
    >> ?? ?? wrote:
    >> ??
    >> ?? ?
    >> ?? ?John Larkin wrote:
    >> ?? ??
    >> ?? ?? We're basically doing the same calculation, demonstrating that #12 (or
    >> ?? ?? 14) is plenty good enough.
    >> ?? ?
    >> ?? ?
    >> ?? ? Until the motor or compressor is replaced with a larger unit. Then
    >> ?? ?all bets are off. It's cheaper to do it right the first time. You
    >> ?? ?could even put a small breaker box by the compressor ? run AWG 6 to it,
    >> ?? ?to power other tools, as needed without starting from scratch.
    >> ??
    >> ?? Well, then why stop at #6? Run 3KV and a distribution transformer. You
    >> ?? never know.
    >> ?
    >> ?
    >> ? Who uses 3KV?
    >>
    >> OK, 300K.

    >
    >
    > Inside your home? Or where you work?


    Hey, you never know how big of a compressor you might need.
     
    , Dec 30, 2012
    #16
  17. DaveC

    rickman Guest

    On 12/29/2012 3:05 PM, DaveC wrote:
    >> Until the motor or compressor is replaced with a larger unit. Then
    >> all bets are off. It's cheaper to do it right the first time. You
    >> could even put a small breaker box by the compressor& run AWG 6 to it,
    >> to power other tools, as needed without starting from scratch.

    >
    > 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.
    >
    > Thanks.
    >


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

    Rick
     
    rickman, Dec 30, 2012
    #17
  18. DaveC

    SoothSayer Guest

    On Sun, 30 Dec 2012 01:28:08 -0500, rickman <> wrote:

    >On 12/29/2012 3:05 PM, DaveC wrote:
    >>> Until the motor or compressor is replaced with a larger unit. Then
    >>> all bets are off. It's cheaper to do it right the first time. You
    >>> could even put a small breaker box by the compressor& run AWG 6 to it,
    >>> to power other tools, as needed without starting from scratch.

    >>
    >> 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.
    >>
    >> Thanks.
    >>

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


    What utter idiot suggested #6?
     
    SoothSayer, Dec 30, 2012
    #18
  19. On Sun, 30 Dec 2012 01:28:08 -0500, the renowned rickman
    <> wrote:

    >On 12/29/2012 3:05 PM, DaveC wrote:
    >>> Until the motor or compressor is replaced with a larger unit. Then
    >>> all bets are off. It's cheaper to do it right the first time. You
    >>> could even put a small breaker box by the compressor& run AWG 6 to it,
    >>> to power other tools, as needed without starting from scratch.

    >>
    >> 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.
    >>
    >> Thanks.
    >>

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


    It's also a sweaty PITA to pull.. ( I ran some to a manly (for single
    phase) compressor and kiln).


    Best regards,
    Spehro Pefhany
    --
    "it's the network..." "The Journey is the reward"
    Info for manufacturers: http://www.trexon.com
    Embedded software/hardware/analog Info for designers: http://www.speff.com
     
    Spehro Pefhany, Dec 30, 2012
    #19
  20. DaveC

    Jasen Betts Guest

    On 2012-12-29, Michael A. Terrell <> wrote:
    >
    > John Larkin wrote:
    >>
    >> We're basically doing the same calculation, demonstrating that #12 (or
    >> 14) is plenty good enough.

    >
    >
    > Until the motor or compressor is replaced with a larger unit.


    a larger compresser is likely to have a soft start where the pump
    compression is releived come on until it's up to speed.




    --
    ⚂⚃ 100% natural

    --- news://freenews.netfront.net/ - complaints: ---
     
    Jasen Betts, Dec 30, 2012
    #20
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