Power mains question: wire gauge

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

  1. On Wed, 02 Jan 2013 09:51:41 -0500, wrote:

    >On Wed, 02 Jan 2013 06:47:36 -0800, DraconisExtinctor
    ><> wrote:
    >
    >>On Wed, 02 Jan 2013 09:33:25 -0500, wrote:
    >>
    >>>On Tue, 01 Jan 2013 21:57:26 -0800, DraconisExtinctor
    >>><> wrote:
    >>>
    >>>>On Tue, 01 Jan 2013 23:10:28 -0500, wrote:
    >>>>
    >>>>>Good Lord, you've taken the AlwaysWrong KoolAid, along with Fields.
    >>>>
    >>>>
    >>>> Says the idiot that reads "plastic" and morphs it into "PVC".
    >>>>
    >>>> You are a true retard.
    >>>
    >>>Plastic water pipe *is* PVC, moron.

    >>
    >> Plastic AIR piping is NOT, you absolute foot right fucking straight
    >>into the mouth dumbfuck!

    >
    >You implied that it could be used, AlwaysWrong.


    NO! I DID NO SUCH THING! EVER! You fucking RETARD!
    >
    >> I never said ANYTHING about using water pipe. EVER. Get a clue,
    >>dipshit.

    >
    >You're a liar, AlwaysWrong. ...but you know that as well as everyone
    >else.


    The person who mentioned PVC is who fucked up. Let's go take a look at
    who that was... Oh, that's right... it was YOU, you fucking
    RETARD-RW.

    YOU mentioned incorrect media. To which I immediately responded is the
    WRONG choice.

    YOU can squirm all you want, but the truth will not change.
     
    DraconisExtinctor, Jan 2, 2013
    #81
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  2. DaveC

    Guest

    On Wed, 02 Jan 2013 10:46:18 -0600, John Fields
    <> wrote:

    >On Wed, 02 Jan 2013 09:32:54 -0500, wrote:
    >
    >>On Wed, 02 Jan 2013 06:06:43 -0600, John Fields
    >><> wrote:
    >>
    >>>On Tue, 01 Jan 2013 17:49:02 -0500, wrote:
    >>>
    >>>>On Tue, 01 Jan 2013 16:30:04 -0600, John Fields
    >>>><> wrote:
    >>>>
    >>>>>On Tue, 01 Jan 2013 17:07:46 -0500, wrote:
    >>>>>
    >>>>>>On Tue, 01 Jan 2013 16:04:11 -0600, John Fields
    >>>>>><> wrote:
    >>>>>>
    >>>>>>>On Sun, 30 Dec 2012 20:25:38 -0500, wrote:
    >>>>>>>
    >>>>>>>>On Sun, 30 Dec 2012 18:28:00 -0500, "Michael A. Terrell"
    >>>>>>>><> wrote:
    >>>>>>>>
    >>>>>>>>>
    >>>>>>>>> wrote:
    >>>>>>>>>>
    >>>>>>>>>> Tom Biasi wrote:
    >>>>>>>>>> ??
    >>>>>>>>>> ?How about run what you need now with a pull string included?
    >>>>>>>>>>
    >>>>>>>>>> I think we have a winner!
    >>>>>>>>>
    >>>>>>>>>
    >>>>>>>>> How much wire have you pulled?
    >>>>>>>>
    >>>>>>>>Enough to know I detest anything approaching 36 wire. An a appeal to
    >>>>>>>>authority? Come on.
    >>>>>>>
    >>>>>>>---
    >>>>>>>Clearly it's difficult to pull #36 wire through conduit, but with your
    >>>>>>>professed expertise in all things non-trivial, one would think you'd
    >>>>>>>relish, rather than detest, the challenge.
    >>>>>>
    >>>>>>You're as clueless as Michael. Actually more, since I corrected the
    >>>>>>tupo some time back.
    >>>>>
    >>>>>---
    >>>>>You really didn't, since all you made reference to was the missing #
    >>>>>sign, but not its location in the string.
    >>>>
    >>>>You really are as stupid as DimBulb. Look what's above the "3" on
    >>>>your keyboard.
    >>>>
    >>>>>Sloppy work all around, but then that's just you...
    >>>>
    >>>>No, you simply can't think, but that's nothing new to anyone here.
    >>>
    >>>---
    >>>Speaking about not thinking,

    >>
    >>You are the expert at not thinking.

    >
    >---
    >Of course; that's why it's so easy to see through your sad little
    >charade of literacy.


    Of course you project you inadequacies on others. It's always been
    your MO.


    >>> it's interesting to note that, in an
    >>>argument, whenever you come up against the stops because of your
    >>>limited capability to use logic and reason - which you demonstrate ad
    >>>nauseam - you always revert to ad hominem.

    >>
    >>You're funny, Fields. Too bad you're such an idiot. You don't even
    >>know that <shift>3 is "#", even though it's right in front of your
    >>stupid nose.

    >
    >Oh, I had no trouble with that,


    You're a liar.

    >I was just referring to the fact that
    >you didn't mention where in the string the "#" is supposed to be,
    >which made your statement ambiguous.


    You're a liar. But that's nothing new.
     
    , Jan 2, 2013
    #82
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  3. DaveC

    Guest

    On Wed, 02 Jan 2013 07:08:55 -0800, DraconisExtinctor
    <> wrote:

    >On Wed, 02 Jan 2013 09:51:41 -0500, wrote:
    >
    >>On Wed, 02 Jan 2013 06:47:36 -0800, DraconisExtinctor
    >><> wrote:
    >>
    >>>On Wed, 02 Jan 2013 09:33:25 -0500, wrote:
    >>>
    >>>>On Tue, 01 Jan 2013 21:57:26 -0800, DraconisExtinctor
    >>>><> wrote:
    >>>>
    >>>>>On Tue, 01 Jan 2013 23:10:28 -0500, wrote:
    >>>>>
    >>>>>>Good Lord, you've taken the AlwaysWrong KoolAid, along with Fields.
    >>>>>
    >>>>>
    >>>>> Says the idiot that reads "plastic" and morphs it into "PVC".
    >>>>>
    >>>>> You are a true retard.
    >>>>
    >>>>Plastic water pipe *is* PVC, moron.
    >>>
    >>> Plastic AIR piping is NOT, you absolute foot right fucking straight
    >>>into the mouth dumbfuck!

    >>
    >>You implied that it could be used, AlwaysWrong.

    >
    > NO! I DID NO SUCH THING! EVER! You fucking RETARD!


    AlwaysWrong runs away from his own position. Who wudda thunk!

    <AlwaysWrong babble snipped>
     
    , Jan 2, 2013
    #83
  4. DaveC

    Guest

    On Wed, 02 Jan 2013 15:40:40 -0600, John Fields
    <> wrote:

    >On Wed, 02 Jan 2013 13:08:11 -0500, wrote:
    >
    >>On Wed, 02 Jan 2013 10:46:18 -0600, John Fields
    >><> wrote:

    >
    >>>>> it's interesting to note that, in an
    >>>>>argument, whenever you come up against the stops because of your
    >>>>>limited capability to use logic and reason - which you demonstrate ad
    >>>>>nauseam - you always revert to ad hominem.
    >>>>
    >>>>You're funny, Fields. Too bad you're such an idiot. You don't even
    >>>>know that <shift>3 is "#", even though it's right in front of your
    >>>>stupid nose.

    >
    >---
    >See what I mean?


    I don't need you to tell me you're stupid. Like DimBulb, you
    advertise the fact constantly.
     
    , Jan 2, 2013
    #84
  5. DaveC

    DarkMatter Guest

    On Wed, 02 Jan 2013 18:27:08 -0500, wrote:

    >On Wed, 02 Jan 2013 15:40:40 -0600, John Fields
    ><> wrote:
    >
    >>On Wed, 02 Jan 2013 13:08:11 -0500, wrote:
    >>
    >>>On Wed, 02 Jan 2013 10:46:18 -0600, John Fields
    >>><> wrote:

    >>
    >>>>>> it's interesting to note that, in an
    >>>>>>argument, whenever you come up against the stops because of your
    >>>>>>limited capability to use logic and reason - which you demonstrate ad
    >>>>>>nauseam - you always revert to ad hominem.
    >>>>>
    >>>>>You're funny, Fields. Too bad you're such an idiot. You don't even
    >>>>>know that <shift>3 is "#", even though it's right in front of your
    >>>>>stupid nose.

    >>
    >>---
    >>See what I mean?

    >
    >I don't need you to tell me you're stupid. Like DimBulb, you
    >advertise the fact constantly.


    The blind shall not see...

    This is why, despite the only pre-requisite being a pre-death
    repentance, most sinners will *still* not ever be saved.

    Despite being told that you were acting like an adolescent worm, you
    continued to do so, and enhanced your pathetic wormage even further.

    You illustrate for the intelligent among us, just what the flaws in the
    human race are.

    Not with your diatribes, but with your attempts at making a diatribe.
    It borders on funny, considering that you tout yourself as intelligent
    and civil.

    Your senility onset is showing again.

    Must be that curse I put on you about 8 years ago, when you started
    your baby bullshit back then, over in a.e.e. I hope the pain settles in
    soon.

    Maybe you can figure out why an Easy-Bake-Oven works better with a 100W
    heating coil than it does with a 100 W light bulb.
     
    DarkMatter, Jan 3, 2013
    #85
  6. DaveC

    josephkk Guest

    On Sat, 29 Dec 2012 11:04:23 -0800, John Larkin
    <> wrote:

    >On Sat, 29 Dec 2012 12:20:01 -0600, John Fields
    ><> wrote:
    >
    >>On Fri, 28 Dec 2012 16:05:49 -0800, John Larkin
    >><> 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 dueto
    >>>>start current.
    >>>>
    >>>>With such a distance, is it recommend to up-scale the wire to 10 ga?
    >>>>
    >>>>Thanks.
    >>>
    >>>#12 is 1.6 mohms/foot. That's 0.32 ohms total. The short-circuit
    >>>current from 220 volts is almost 700 amps. A half horse is only around
    >>>400 watts, about 2 amps. I'd use #14.

    >>
    >>---
    >>The short circuit current through the wire resistance is irrelevant.

    >
    >It is not. If 700 amps is available, there's a huge margin for the
    >startup current for a dinky motor like this one. And plenty of current
    >to blow a breaker if needed.
    >

    No John Larkin, you are full of baloney on this one. I do the wire gauge
    for motor starts all the time. I(sc) is NOT used.
    >
    >>What matters is the stall current through the motor when it's starting
    >>up; no doubt the 15A the OP mentioned.

    >
    >Exactly. It needs 15, we have 700. We don't need #10 wire.
    >

    Incorrect setup. What is of concern is the drop during motor start. Not
    motor run and not wiring fault conditions. The goal is to keep it below
    5% including all other losses to the service transformer. Generally a 2%
    to 3% drop during normal operation, and no more than 8% during motor
    start, is allowed in the building, all the way to the main service lugs.

    Thus #14 is a bit wimpy but #12 is fine. No real advantage going to #10.
    >>
    >>14AWG is till a good call though, since 15A will drop only about 7.5V
    >>across the run.

    >
    >We're basically doing the same calculation, demonstrating that #12 (or
    >14) is plenty good enough.
    >
     
    josephkk, Jan 3, 2013
    #86
  7. DaveC

    josephkk Guest

    On Mon, 31 Dec 2012 16:54:41 -0500, wrote:

    >On Mon, 31 Dec 2012 13:50:29 -0800, John Larkin
    ><> wrote:
    >
    >>On Mon, 31 Dec 2012 15:08:00 -0500, wrote:
    >>
    >>>On Mon, 31 Dec 2012 12:28:31 -0500, "Michael A. Terrell"
    >>><> wrote:
    >>>
    >>>>

    <snip>
    >>>> He said he was going to suggest it to the owner, so who knows.
    >>>
    >>>So why not 500KV? You never know?

    >>
    >>Why not put the compressor where the power is, and run an air hose?
    >>Then we could argue about ths size of the hose.

    >
    >Actually, that's what I plan to do. Put the compressor in the garage
    >and pipe the air downstairs. 4" oughtta do it. ;-)
    >
    >I just have to figure out how much work it's going to be (how things
    >line up).


    4" really? How big it that compressor, 500 kW? Does it go over 3000'?
    Not that i am all that expert but that is the size of compressor and the
    run length i saw last time i saw one plumbed at 4". And that one was done
    by an expert.

    ?-)
     
    josephkk, Jan 3, 2013
    #87
  8. DaveC

    josephkk Guest

    On Sat, 29 Dec 2012 16:40:07 -0500, wrote:

    >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. ;-)


    Conduit is mentioned in the leadoff post by OP. The cost of putting in
    conduit almost completely swamps the wire gauge issue.

    ?-)
     
    josephkk, Jan 3, 2013
    #88
  9. DaveC

    josephkk Guest

    On Mon, 31 Dec 2012 19:24:24 -0500, wrote:

    >On Mon, 31 Dec 2012 17:45:13 -0500, "Michael A. Terrell"
    ><> wrote:
    >
    >>
    >> wrote:
    >>>
    >>> It doesn't matter what *YOU* have on hand. #12 works just fine and is
    >>> about 1/3 the cost of #10.

    >>
    >>
    >> Do they use lube on you when you buy 10 AWG? It has 50% more copper
    >>per foot. If you pay 200% more per foot, you've been raped. Do whatever
    >>the hell you like, no one else cares.

    >
    >#12 is normal stuff, sold by the pallet at HD. #10 is "special" and
    >quite expensive because of it. Anything outside the norm has a
    >premium attached to it. For example, 12-3 has only 33% more copper
    >than 12-2 but costs almost double ($120 vs. $70 per 250' roll). And,
    >10-2 is $135 per roll, so yes, *DOUBLE*.
    >
    >When *was* the last time you bought this stuff? You really need to
    >get out more and bitch less.



    Small wonder you get raped on #10. You don't know where to buy stuff.

    ?-)
     
    josephkk, Jan 3, 2013
    #89
  10. DaveC

    Guest

    On Wed, 02 Jan 2013 19:11:54 -0800, josephkk
    <> wrote:

    >On Mon, 31 Dec 2012 16:54:41 -0500, wrote:
    >
    >>On Mon, 31 Dec 2012 13:50:29 -0800, John Larkin
    >><> wrote:
    >>
    >>>On Mon, 31 Dec 2012 15:08:00 -0500, wrote:
    >>>
    >>>>On Mon, 31 Dec 2012 12:28:31 -0500, "Michael A. Terrell"
    >>>><> wrote:
    >>>>
    >>>>>

    ><snip>
    >>>>> He said he was going to suggest it to the owner, so who knows.
    >>>>
    >>>>So why not 500KV? You never know?
    >>>
    >>>Why not put the compressor where the power is, and run an air hose?
    >>>Then we could argue about ths size of the hose.

    >>
    >>Actually, that's what I plan to do. Put the compressor in the garage
    >>and pipe the air downstairs. 4" oughtta do it. ;-)
    >>
    >>I just have to figure out how much work it's going to be (how things
    >>line up).

    >
    >4" really?


    Of course not. Michael is being silly with his suggestion of running
    #6 wire for the compressor. I thought I'd join in. For anything I've
    done, 1/2" Type-L copper is fine. That's probably what I'll use again
    but it's getting rather pricey.

    > How big it that compressor, 500 kW? Does it go over 3000'?
    >Not that i am all that expert but that is the size of compressor and the
    >run length i saw last time i saw one plumbed at 4". And that one was done
    >by an expert.
     
    , Jan 3, 2013
    #90
  11. DaveC

    Guest

    On Wed, 02 Jan 2013 19:16:15 -0800, josephkk
    <> wrote:

    >On Sat, 29 Dec 2012 16:40:07 -0500, wrote:
    >
    >>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. ;-)

    >
    >Conduit is mentioned in the leadoff post by OP. The cost of putting in
    >conduit almost completely swamps the wire gauge issue.


    Agreed, sorta. PVC isn't too bad, though. This whole thing has
    gotten absurd.
     
    , Jan 3, 2013
    #91
  12. DaveC

    Guest

    On Wed, 02 Jan 2013 18:44:15 -0800, DarkMatter
    <> wrote:

    >On Wed, 02 Jan 2013 18:27:08 -0500, wrote:
    >
    >>On Wed, 02 Jan 2013 15:40:40 -0600, John Fields
    >><> wrote:
    >>
    >>>On Wed, 02 Jan 2013 13:08:11 -0500, wrote:
    >>>
    >>>>On Wed, 02 Jan 2013 10:46:18 -0600, John Fields
    >>>><> wrote:
    >>>
    >>>>>>> it's interesting to note that, in an
    >>>>>>>argument, whenever you come up against the stops because of your
    >>>>>>>limited capability to use logic and reason - which you demonstrate ad
    >>>>>>>nauseam - you always revert to ad hominem.
    >>>>>>
    >>>>>>You're funny, Fields. Too bad you're such an idiot. You don't even
    >>>>>>know that <shift>3 is "#", even though it's right in front of your
    >>>>>>stupid nose.
    >>>
    >>>---
    >>>See what I mean?

    >>
    >>I don't need you to tell me you're stupid. Like DimBulb, you
    >>advertise the fact constantly.

    >
    > The blind shall not see...


    Those who are always wrong, are certainly stupid, AlwaysWrong.

    <nothing more needs to be known about AlwaysWrong>
     
    , Jan 3, 2013
    #92
  13. DaveC

    Guest

    On Wed, 02 Jan 2013 19:34:04 -0800, josephkk
    <> wrote:

    >On Mon, 31 Dec 2012 19:24:24 -0500, wrote:
    >
    >>On Mon, 31 Dec 2012 17:45:13 -0500, "Michael A. Terrell"
    >><> wrote:
    >>
    >>>
    >>> wrote:
    >>>>
    >>>> It doesn't matter what *YOU* have on hand. #12 works just fine and is
    >>>> about 1/3 the cost of #10.
    >>>
    >>>
    >>> Do they use lube on you when you buy 10 AWG? It has 50% more copper
    >>>per foot. If you pay 200% more per foot, you've been raped. Do whatever
    >>>the hell you like, no one else cares.

    >>
    >>#12 is normal stuff, sold by the pallet at HD. #10 is "special" and
    >>quite expensive because of it. Anything outside the norm has a
    >>premium attached to it. For example, 12-3 has only 33% more copper
    >>than 12-2 but costs almost double ($120 vs. $70 per 250' roll). And,
    >>10-2 is $135 per roll, so yes, *DOUBLE*.
    >>
    >>When *was* the last time you bought this stuff? You really need to
    >>get out more and bitch less.

    >
    >
    >Small wonder you get raped on #10. You don't know where to buy stuff.
    >


    When was the last time you bought wire?
     
    , Jan 3, 2013
    #93
  14. On Wed, 02 Jan 2013 22:57:50 -0500, the renowned wrote:

    >On Wed, 02 Jan 2013 19:11:54 -0800, josephkk
    ><> wrote:
    >
    >>On Mon, 31 Dec 2012 16:54:41 -0500, wrote:
    >>
    >>>On Mon, 31 Dec 2012 13:50:29 -0800, John Larkin
    >>><> wrote:
    >>>
    >>>>On Mon, 31 Dec 2012 15:08:00 -0500, wrote:
    >>>>
    >>>>>On Mon, 31 Dec 2012 12:28:31 -0500, "Michael A. Terrell"
    >>>>><> wrote:
    >>>>>
    >>>>>>

    >><snip>
    >>>>>> He said he was going to suggest it to the owner, so who knows.
    >>>>>
    >>>>>So why not 500KV? You never know?
    >>>>
    >>>>Why not put the compressor where the power is, and run an air hose?
    >>>>Then we could argue about ths size of the hose.
    >>>
    >>>Actually, that's what I plan to do. Put the compressor in the garage
    >>>and pipe the air downstairs. 4" oughtta do it. ;-)
    >>>
    >>>I just have to figure out how much work it's going to be (how things
    >>>line up).

    >>
    >>4" really?

    >
    >Of course not. Michael is being silly with his suggestion of running
    >#6 wire for the compressor. I thought I'd join in. For anything I've
    >done, 1/2" Type-L copper is fine. That's probably what I'll use again
    >but it's getting rather pricey.


    Protectionism at work:-
    http://www.bloomberg.com/news/2010-...on-china-mexico-made-copper-piping-tubes.html



    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, Jan 3, 2013
    #94
  15. DaveC

    John S Guest

    On 1/2/2013 8:48 PM, josephkk wrote:
    > On Sat, 29 Dec 2012 11:04:23 -0800, John Larkin
    > <> wrote:
    >
    >> On Sat, 29 Dec 2012 12:20:01 -0600, John Fields
    >> <> wrote:
    >>
    >>> On Fri, 28 Dec 2012 16:05:49 -0800, John Larkin
    >>> <> 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.
    >>>>
    >>>> #12 is 1.6 mohms/foot. That's 0.32 ohms total. The short-circuit
    >>>> current from 220 volts is almost 700 amps. A half horse is only around
    >>>> 400 watts, about 2 amps. I'd use #14.
    >>>
    >>> ---
    >>> The short circuit current through the wire resistance is irrelevant.

    >>
    >> It is not. If 700 amps is available, there's a huge margin for the
    >> startup current for a dinky motor like this one. And plenty of current
    >> to blow a breaker if needed.
    >>

    > No John Larkin, you are full of baloney on this one. I do the wire gauge
    > for motor starts all the time. I(sc) is NOT used.
    >>
    >>> What matters is the stall current through the motor when it's starting
    >>> up; no doubt the 15A the OP mentioned.

    >>
    >> Exactly. It needs 15, we have 700. We don't need #10 wire.
    >>

    > Incorrect setup. What is of concern is the drop during motor start. Not
    > motor run and not wiring fault conditions. The goal is to keep it below
    > 5% including all other losses to the service transformer. Generally a 2%
    > to 3% drop during normal operation, and no more than 8% during motor
    > start, is allowed in the building, all the way to the main service lugs.


    I'm curious about this. Doesn't a motor draw about 6-10 times FLA during
    start? If so, wouldn't that cause a 18-30% drop during start if you have
    a 3% drop normally? Or, looking at it the other way, if you size for 8%
    starting drop, your normal operating drop would be only 1.3%.
     
    John S, Jan 3, 2013
    #95
  16. DaveC

    Guest

    On Thu, 03 Jan 2013 03:23:32 -0500, Spehro Pefhany
    <> wrote:

    >On Wed, 02 Jan 2013 22:57:50 -0500, the renowned wrote:
    >
    >>On Wed, 02 Jan 2013 19:11:54 -0800, josephkk
    >><> wrote:
    >>
    >>>On Mon, 31 Dec 2012 16:54:41 -0500, wrote:
    >>>
    >>>>On Mon, 31 Dec 2012 13:50:29 -0800, John Larkin
    >>>><> wrote:
    >>>>
    >>>>>On Mon, 31 Dec 2012 15:08:00 -0500, wrote:
    >>>>>
    >>>>>>On Mon, 31 Dec 2012 12:28:31 -0500, "Michael A. Terrell"
    >>>>>><> wrote:
    >>>>>>
    >>>>>>>
    >>><snip>
    >>>>>>> He said he was going to suggest it to the owner, so who knows.
    >>>>>>
    >>>>>>So why not 500KV? You never know?
    >>>>>
    >>>>>Why not put the compressor where the power is, and run an air hose?
    >>>>>Then we could argue about ths size of the hose.
    >>>>
    >>>>Actually, that's what I plan to do. Put the compressor in the garage
    >>>>and pipe the air downstairs. 4" oughtta do it. ;-)
    >>>>
    >>>>I just have to figure out how much work it's going to be (how things
    >>>>line up).
    >>>
    >>>4" really?

    >>
    >>Of course not. Michael is being silly with his suggestion of running
    >>#6 wire for the compressor. I thought I'd join in. For anything I've
    >>done, 1/2" Type-L copper is fine. That's probably what I'll use again
    >>but it's getting rather pricey.

    >
    >Protectionism at work:-
    >http://www.bloomberg.com/news/2010-...on-china-mexico-made-copper-piping-tubes.html
    >

    Unbelievable. With the housing market in the tank and commodities
    through the roof, what the housing market really needs *more* help
    from UncleS. <sheesh>
     
    , Jan 3, 2013
    #96
  17. DaveC

    Guest

    On Thu, 03 Jan 2013 02:23:36 -0600, John Fields
    <> wrote:

    >On Wed, 02 Jan 2013 18:27:08 -0500, wrote:
    >
    >>On Wed, 02 Jan 2013 15:40:40 -0600, John Fields
    >><> wrote:
    >>
    >>>On Wed, 02 Jan 2013 13:08:11 -0500, wrote:
    >>>
    >>>>On Wed, 02 Jan 2013 10:46:18 -0600, John Fields
    >>>><> wrote:
    >>>
    >>>>>>> it's interesting to note that, in an
    >>>>>>>argument, whenever you come up against the stops because of your
    >>>>>>>limited capability to use logic and reason - which you demonstrate ad
    >>>>>>>nauseam - you always revert to ad hominem.
    >>>>>>
    >>>>>>You're funny, Fields. Too bad you're such an idiot. You don't even
    >>>>>>know that <shift>3 is "#", even though it's right in front of your
    >>>>>>stupid nose.
    >>>
    >>>---
    >>>See what I mean?

    >>
    >>I don't need you to tell me you're stupid. Like DimBulb, you
    >>advertise the fact constantly.

    >
    >---
    >You just can't help yourself, can you?


    You're just helpless.
     
    , Jan 3, 2013
    #97
  18. DaveC

    SoothSayer Guest

    On Thu, 03 Jan 2013 08:10:27 -0600, John Fields
    <> wrote:

    >On Thu, 03 Jan 2013 06:40:26 -0600, John S <>
    >wrote:
    >
    >>On 1/2/2013 8:48 PM, josephkk wrote:
    >>> On Sat, 29 Dec 2012 11:04:23 -0800, John Larkin
    >>> <> wrote:
    >>>
    >>>> On Sat, 29 Dec 2012 12:20:01 -0600, John Fields
    >>>> <> wrote:
    >>>>
    >>>>> On Fri, 28 Dec 2012 16:05:49 -0800, John Larkin
    >>>>> <> 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.
    >>>>>>
    >>>>>> #12 is 1.6 mohms/foot. That's 0.32 ohms total. The short-circuit
    >>>>>> current from 220 volts is almost 700 amps. A half horse is only around
    >>>>>> 400 watts, about 2 amps. I'd use #14.
    >>>>>
    >>>>> ---
    >>>>> The short circuit current through the wire resistance is irrelevant.
    >>>>
    >>>> It is not. If 700 amps is available, there's a huge margin for the
    >>>> startup current for a dinky motor like this one. And plenty of current
    >>>> to blow a breaker if needed.
    >>>>
    >>> No John Larkin, you are full of baloney on this one. I do the wire gauge
    >>> for motor starts all the time. I(sc) is NOT used.
    >>>>
    >>>>> What matters is the stall current through the motor when it's starting
    >>>>> up; no doubt the 15A the OP mentioned.
    >>>>
    >>>> Exactly. It needs 15, we have 700. We don't need #10 wire.
    >>>>
    >>> Incorrect setup. What is of concern is the drop during motor start. Not
    >>> motor run and not wiring fault conditions. The goal is to keep it below
    >>> 5% including all other losses to the service transformer. Generally a 2%
    >>> to 3% drop during normal operation, and no more than 8% during motor
    >>> start, is allowed in the building, all the way to the main service lugs.

    >>
    >>I'm curious about this. Doesn't a motor draw about 6-10 times FLA during
    >>start? If so, wouldn't that cause a 18-30% drop during start if you have
    >>a 3% drop normally? Or, looking at it the other way, if you size for 8%
    >>starting drop, your normal operating drop would be only 1.3%.

    >
    >---
    >From the OP's example we have a 240VAC 1/2HP motor with a startup
    >current of 15A being fed through 200 feet of #14 AWG wire.
    >
    >1HP is 746 watts, so if his motor delivers 1/2HP at the shaft and it's
    >80% efficient it'll be taking about 467 watts from the mains under
    >full load.
    >
    >200 feet of #14 solid copper looks like about half an ohm, so we have,
    >for the startup case:
    >
    > 15A--->
    >240AC>---[0.25R]---+ <------+
    > | |
    > [16R] 233V
    > | |
    >240AC>---[0.25R]---+ <------+
    >
    >Because of the wire resistance, instead of 15A in the circuit we'll
    >have 14.55A, and that will drop 233V across the motor.
    >
    >233V is 97% of 240V, so there's only a 3% loss in the wire.
    >
    >In the full load case we have this:
    >
    > 1.94A--->
    >240AC>---[0.25R]---+ <------+
    > | |
    > [123R] 239V
    > | |
    >240AC>---[0.25R]---+ <------+
    >
    >so the loss is less than half a percent.



    That is right on the mark.

    It was always fun to un a 100 foot extension cord to a construction
    work area and run a device like a circular saw or such. Then try it with
    two 100 foot cords together for 200 feet. It (the difference) is very
    noticeable.

    Most of those cords are #14 at those lengths (or they'd better be), but
    at the price difference for raw wire and a buried run, I'd say that
    dropping to #12 or eve the #10 run was not an improper suggestion,
    considering it was going to be a permanent install, and the device being
    powered may not be, and wiring a service outlet is what we are doing.

    So, yes, as you illustrate, #14 is sufficient, even good, considering
    what I have seen houses and such wired with.

    At 200 feet away, and not knowing if the device will be the only item
    being powered, I would at least examine the cost tables for the job using
    #10, #12 and #14 Thhn, no conduit.

    As far as the conduit goes though, if one gets small diameter PVC, and
    all the fittings, no 200 foot pull needs to be done. The segments and
    fittings can all be fed down the wire bundle and build the conduit in
    place right on the wires, then bury the finished run.
     
    SoothSayer, Jan 3, 2013
    #98
  19. DaveC

    bud-- Guest

    On 1/3/2013 8:10 AM, John Fields wrote:
    > On Thu, 03 Jan 2013 06:40:26 -0600, John S<>
    > wrote:
    >
    >> On 1/2/2013 8:48 PM, josephkk wrote:
    >>> On Sat, 29 Dec 2012 11:04:23 -0800, John Larkin
    >>> <> wrote:
    >>>
    >>>> On Sat, 29 Dec 2012 12:20:01 -0600, John Fields
    >>>> <> wrote:
    >>>>
    >>>>> On Fri, 28 Dec 2012 16:05:49 -0800, John Larkin
    >>>>> <> 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.
    >>>>>>
    >>>>>> #12 is 1.6 mohms/foot. That's 0.32 ohms total. The short-circuit
    >>>>>> current from 220 volts is almost 700 amps. A half horse is only around
    >>>>>> 400 watts, about 2 amps. I'd use #14.
    >>>>>
    >>>>> ---
    >>>>> The short circuit current through the wire resistance is irrelevant.
    >>>>
    >>>> It is not. If 700 amps is available, there's a huge margin for the
    >>>> startup current for a dinky motor like this one. And plenty of current
    >>>> to blow a breaker if needed.
    >>>>
    >>> No John Larkin, you are full of baloney on this one. I do the wire gauge
    >>> for motor starts all the time. I(sc) is NOT used.
    >>>>
    >>>>> What matters is the stall current through the motor when it's starting
    >>>>> up; no doubt the 15A the OP mentioned.
    >>>>
    >>>> Exactly. It needs 15, we have 700. We don't need #10 wire.
    >>>>
    >>> Incorrect setup. What is of concern is the drop during motor start. Not
    >>> motor run and not wiring fault conditions. The goal is to keep it below
    >>> 5% including all other losses to the service transformer. Generally a 2%
    >>> to 3% drop during normal operation, and no more than 8% during motor
    >>> start, is allowed in the building, all the way to the main service lugs.

    >>
    >> I'm curious about this. Doesn't a motor draw about 6-10 times FLA during
    >> start? If so, wouldn't that cause a 18-30% drop during start if you have
    >> a 3% drop normally? Or, looking at it the other way, if you size for 8%
    >> starting drop, your normal operating drop would be only 1.3%.

    >
    > ---
    > From the OP's example we have a 240VAC 1/2HP motor with a startup
    > current of 15A being fed through 200 feet of #14 AWG wire.
    >
    > 1HP is 746 watts, so if his motor delivers 1/2HP at the shaft and it's
    > 80% efficient it'll be taking about 467 watts from the mains under
    > full load.
    >
    > 200 feet of #14 solid copper looks like about half an ohm, so we have,
    > for the startup case:
    >
    > 15A--->
    > 240AC>---[0.25R]---+<------+
    > | |
    > [16R] 233V
    > | |
    > 240AC>---[0.25R]---+<------+
    >
    > Because of the wire resistance, instead of 15A in the circuit we'll
    > have 14.55A, and that will drop 233V across the motor.
    >
    > 233V is 97% of 240V, so there's only a 3% loss in the wire.
    >
    > In the full load case we have this:
    >
    > 1.94A--->
    > 240AC>---[0.25R]---+<------+
    > | |
    > [123R] 239V
    > | |
    > 240AC>---[0.25R]---+<------+
    >
    > so the loss is less than half a percent.
    >


    The NEC gives the full load current of a 1/2 HP 230V motor as 4.9 A.
    Power factor adds to the motor current. (In most cases this will be
    high, but is used to determine wire size.)

    The NEC gives the locked rotor amps as 29.4 (which is 6x the running amps).

    The NEC gives the resistance of 200 ft of #12 as 0.62 ohms (about the
    same as you used).

    The running voltage drop is 4.9V = 3%.
    The starting (locked rotor) voltage drop is 18.2V = 7.6%.

    #14 sounds reasonable. Can't remember if the motor was actually 1/2 HP.
     
    bud--, Jan 3, 2013
    #99
  20. DaveC

    John S Guest

    On 1/3/2013 9:14 AM, bud-- wrote:
    > On 1/3/2013 8:10 AM, John Fields wrote:
    >> On Thu, 03 Jan 2013 06:40:26 -0600, John S<>
    >> wrote:
    >>
    >>> On 1/2/2013 8:48 PM, josephkk wrote:
    >>>> On Sat, 29 Dec 2012 11:04:23 -0800, John Larkin
    >>>> <> wrote:
    >>>>
    >>>>> On Sat, 29 Dec 2012 12:20:01 -0600, John Fields
    >>>>> <> wrote:
    >>>>>
    >>>>>> On Fri, 28 Dec 2012 16:05:49 -0800, John Larkin
    >>>>>> <> 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.
    >>>>>>>
    >>>>>>> #12 is 1.6 mohms/foot. That's 0.32 ohms total. The short-circuit
    >>>>>>> current from 220 volts is almost 700 amps. A half horse is only
    >>>>>>> around
    >>>>>>> 400 watts, about 2 amps. I'd use #14.
    >>>>>>
    >>>>>> ---
    >>>>>> The short circuit current through the wire resistance is irrelevant.
    >>>>>
    >>>>> It is not. If 700 amps is available, there's a huge margin for the
    >>>>> startup current for a dinky motor like this one. And plenty of current
    >>>>> to blow a breaker if needed.
    >>>>>
    >>>> No John Larkin, you are full of baloney on this one. I do the wire
    >>>> gauge
    >>>> for motor starts all the time. I(sc) is NOT used.
    >>>>>
    >>>>>> What matters is the stall current through the motor when it's
    >>>>>> starting
    >>>>>> up; no doubt the 15A the OP mentioned.
    >>>>>
    >>>>> Exactly. It needs 15, we have 700. We don't need #10 wire.
    >>>>>
    >>>> Incorrect setup. What is of concern is the drop during motor
    >>>> start. Not
    >>>> motor run and not wiring fault conditions. The goal is to keep it
    >>>> below
    >>>> 5% including all other losses to the service transformer. Generally
    >>>> a 2%
    >>>> to 3% drop during normal operation, and no more than 8% during motor
    >>>> start, is allowed in the building, all the way to the main service
    >>>> lugs.
    >>>
    >>> I'm curious about this. Doesn't a motor draw about 6-10 times FLA during
    >>> start? If so, wouldn't that cause a 18-30% drop during start if you have
    >>> a 3% drop normally? Or, looking at it the other way, if you size for 8%
    >>> starting drop, your normal operating drop would be only 1.3%.

    >>
    >> ---
    >> From the OP's example we have a 240VAC 1/2HP motor with a startup
    >> current of 15A being fed through 200 feet of #14 AWG wire.
    >>
    >> 1HP is 746 watts, so if his motor delivers 1/2HP at the shaft and it's
    >> 80% efficient it'll be taking about 467 watts from the mains under
    >> full load.
    >>
    >> 200 feet of #14 solid copper looks like about half an ohm, so we have,
    >> for the startup case:
    >>
    >> 15A--->
    >> 240AC>---[0.25R]---+<------+
    >> | |
    >> [16R] 233V
    >> | |
    >> 240AC>---[0.25R]---+<------+
    >>
    >> Because of the wire resistance, instead of 15A in the circuit we'll
    >> have 14.55A, and that will drop 233V across the motor.
    >>
    >> 233V is 97% of 240V, so there's only a 3% loss in the wire.
    >>
    >> In the full load case we have this:
    >>
    >> 1.94A--->
    >> 240AC>---[0.25R]---+<------+
    >> | |
    >> [123R] 239V
    >> | |
    >> 240AC>---[0.25R]---+<------+
    >>
    >> so the loss is less than half a percent.
    >>

    >
    > The NEC gives the full load current of a 1/2 HP 230V motor as 4.9 A.
    > Power factor adds to the motor current. (In most cases this will be
    > high, but is used to determine wire size.)


    I believe the motor current given by the NEC includes efficiency and
    power factor.

    In fact, the NEC info indicates an inefficient motor with a poor power
    factor.

    Motor running VA is the motor volt-amps (4.9 * 230) = 1127.

    The power output of a motor is nameplate horsepower times 746 = .5 * 746
    = 373 Watts.

    The product of motor efficiency and power factor is:
    N*Pf = P/VA where N is efficiency and Pf is power factor. That product
    is 373/1127 = .331

    I know neither the efficiency nor power factor of the NEC's motor, but
    as a quick rough "feel" for the numbers, I can take the square root of
    the .331 = .575. Roughly .6 for power factor and .6 for efficiency.

    If power factor was actually typical of larger HP motors, say .7, then
    the efficiency is .331/.7 = .47 or about 50%.

    Fractional horsepower single phase motors typically have a lower power
    factor and lower efficiency than integral horsepower three-phase motors.

    However, that is not my point.

    >
    > The NEC gives the locked rotor amps as 29.4 (which is 6x the running amps).


    Yes, I was thinking somewhere between 6 and 10 times.

    > The NEC gives the resistance of 200 ft of #12 as 0.62 ohms (about the
    > same as you used).
    >
    > The running voltage drop is 4.9V = 3%.
    > The starting (locked rotor) voltage drop is 18.2V = 7.6%.


    ISTM that if there is a 3% drop at FLA, then the drop will be 6 times
    that at 6 times the current. That would be 18%

    > #14 sounds reasonable. Can't remember if the motor was actually 1/2 HP.


    I am not questioning the wire gauge chosen.
     
    John S, Jan 3, 2013
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