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Adequate wire gauge question.

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  • Adequate wire gauge question.

    I have a 50’ length of electric cable marked Coleman Seoprene 105 10AWG. I would like to use this as an extension cord for my Lincoln 215 MIG welder. Is this wire gauge heavy enough for this long a run? If so that’s great, if not what would be the safe maximum length? Thanks
    Tim

  • #2
    Its good for 30A max, should'nt drop too much voltage for that length, Check your welder manual on how much output current = 30A input current and don't exceed that setting (Except for maybe tack welds)
    Insure it has proper 240v 30A connectors on it, if not install them yourself (a welder should have no use for neutral, so even a 120v 2 conductor (+ground) cable could be used at 240v for a welder, but double check your manual on that)
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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    • #3
      Welders are allowed to exceed the maximum rating of a circuit based on the maximum duty cycle permitted over 10 minutes IIRC. A dedicated welder circuit may be overloaded to a maximum of 200% of the conductor rating and may be protected with an overcurrent device (breaker) rated at no more than 200% of the wire ampacity or the welder maximum current draw, whichever is the lesser based on duty cycle. There is a table in the NEC which spells out how much overload is permitted based on the actual duty cycle of the welding performed and the ampacity of the supply conductors. It is always permissible to overload to the next uprated standard circuit breaker and load current.

      This means that a 30 amp cable may be protected at 40 amps for welder use.
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      • #4
        Originally posted by Evan
        Welders are allowed to exceed the maximum rating of a circuit based on the maximum duty cycle permitted over 10 minutes IIRC. A dedicated welder circuit may be overloaded to a maximum of 200% of the conductor rating and may be protected with an overcurrent device (breaker) rated at no more than 200% of the wire ampacity .........

        This means that a 30 amp cable may be protected at 40 amps for welder use.
        Not actually.

        The 10ga copper is limited to 30A "unless specifically permitted elsewhere in the code".

        Since #10 is very minimal for any welder (and so not in common use for welder supply cable), AND no part of article 630 *specifically* mentions #10, it would actually NOT be permitted under the NEC.

        I would never sanction anything like that on a drawing......
        1601 2137 5683 1002 1437

        Keep eye on ball.
        Hashim Khan

        If you look closely at a digital signal, you find out it is really analog......

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        • #5
          It is specifically permitted in the code. See section 630-12.
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          • #6
            Originally posted by Evan
            Welders are allowed to exceed the maximum rating of a circuit based on the maximum duty cycle permitted over 10 minutes IIRC. A dedicated welder circuit may be overloaded to a maximum of 200% of the conductor rating and may be protected with an overcurrent device (breaker) rated at no more than 200% of the wire ampacity or the welder maximum current draw, whichever is the lesser based on duty cycle. There is a table in the NEC which spells out how much overload is permitted based on the actual duty cycle of the welding performed and the ampacity of the supply conductors. It is always permissible to overload to the next uprated standard circuit breaker and load current.

            This means that a 30 amp cable may be protected at 40 amps for welder use.
            Thanks Evan. I was an electrician all my life and that one never came up. Makes tons of sense though. I wonder if a modern inverter welder has the inrush current of an old transformer type? I suspect that the reasoning behind this article is about the breaker more than the cable. When starting an arc, the old style equipment would have to accelerate a big field that would settle down after saturation. OP, as Evan said, see what the manual says for running vs output current. As J Tiers points out, Engineers can do whatever they want, they just have to sign for the liability when they stray from the code.


            So J, having now read the exception, would you still insist that your client oversize his welder feeder??

            Dan
            Last edited by skyboltone; 11-14-2009, 05:34 PM.

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            • #7
              I've been searching for that manual all day, it can't hide forever.

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              • #8
                The inspectors here will not pass a higher rated breaker than the wire and length of run and socket are rated to handle.

                What "might" be plugged into it is not a consideration.

                In a residential situation the breaker, the wire size, the run, and the outlet must be rated according to code.

                They will not allow a so called "dedicated welder" outlet that exceeds code.
                Gene

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                • #9
                  It isn't exceeding the code. It is specifically permitted by the code.

                  The code:

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                  • #10
                    That won't apply, and I wouldn't pass the drawing if it showed that.

                    It is well known that SPECIFICALLY #10, #12, and #14 are under-rated for current in the code.

                    In MANY places in the code, there are gauge restrictions on usage, such as the sizes allowed to be paralleled, and the like.

                    Unless #10 was specifically called out as THAT GAUGE as allowed, I'd call it NOT allowed.

                    I would allow it for most any "unrestricted" gauge, i.e. 8, 6, etc, but not for 10, 12, or 14. AND not in anything but a welder-specific hard-wired application in an industrial situation.

                    Home use? Never.

                    Most of those small gauges don't apply for any but the smallest welders anyway.


                    ************************************************** ************************************************** **********************

                    But that is fixed wiring.................................. and assumes an overload situation, which we don't have here.

                    Use as an extension cord is somewhat different from use in a fixed wiring situation anyhow. The Lincoln 215 supplies 215A at 22V with 30% duty. The duty cycle timing is not given.

                    The 215A at 22V is 4700W, which is only 20A at 230V. possibly as much as 5000 W input power, or 22A. The 10Ga cable will take that just fine. It is well within rating.
                    Last edited by J Tiers; 11-14-2009, 09:46 PM.
                    1601 2137 5683 1002 1437

                    Keep eye on ball.
                    Hashim Khan

                    If you look closely at a digital signal, you find out it is really analog......

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                    • #11
                      It bloody well does apply. If there is a specific exception to the rule it will be noted, not the other way around. Try reading your Miller manual for a welder intended to run on a 15 or 20 amp circuit. They specifically mention that portion of the elctrical code and how it applies to the wiring and breakers required for the welder.

                      I would allow it for most any "unrestricted" gauge, i.e. 8, 6, etc, but not for 10, 12, or 14.
                      Check the wire gauges below.



                      According to note 1 a breaker up to 30 amps may be used with 12 gauge wire.
                      Last edited by Evan; 11-14-2009, 10:29 PM.
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                      • #12
                        My gut feeling, and nothing to do with regulations etc, is that anything that draws lots of current will work best if the supply voltage to it doesn't drop by much when it's working hard. Even with 10 ga. wire, there's going to be a significant voltage drop over 50 feet when you're drawing 30 or more amps. You might want to temporarily wire it in and see how well it works before stringing the wire.
                        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                        • #13
                          The particular cable the OP has couldn't be better suited to the job. Coleman Seoprene 105 10AWG has an insulation temperature rating of 105 degrees C. It has a nominal ampacity rating of 30 amps with a footnote that higher current may be used in continuous service because of the high temperature insulation rating. It is oil resistant submersible rated fine strand super flexible cable with 30 strands per conductor. Using the NEC welder criteria it can easily be operated at 40 amps and 50 amps in intermittent service.

                          On 240 vac single phase power at a current of 30 amps over 50 feet it will produce a voltage drop of only 1.5 percent. The code permits up to 3 percent in that service so technically it can handle 60 amps intermittent which is 200% of the continuous rating as permitted by section 630.12.

                          I would breaker it at 40 amps although legally you could use a 50 amp breaker if the machine requires it.
                          Last edited by Evan; 11-14-2009, 10:58 PM.
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                          • #14
                            And, since the welder apparently doesn't draw enough at 230V to NEED a higher breaker than is legal with the #10, what's the big deal?

                            it shouldn't draw more than about 30A


                            Evan, you chose a particularly BAD example,

                            While the manual you show recommends a breaker somewhat oversized for the 12 ga wire, the actual current they draw is within the wire rating in both cases

                            17.5A and 12 Ga (nominal limit 20A) and 9.3A and 14 ga (nominal limit 15A.

                            So what they actually suggest as current draw is within the NEC limits for the wire, aside from an oversizing of one breaker by 25%.

                            And, that is for an "industrial welding circuit".

                            When you install that in a HOUSE, it is a "branch circuit", end of story. Nothing about welders etc applies, unless it is WIRED TO a welder.
                            1601 2137 5683 1002 1437

                            Keep eye on ball.
                            Hashim Khan

                            If you look closely at a digital signal, you find out it is really analog......

                            Comment


                            • #15
                              I chose the example because it refers to the code and because it uses 12 and 14 gauge wire which you maintain shouldn't be used for welders and the code doesn't apply to those gauges which is nonsense.

                              The code also makes no mention of a distinction between industrial or home shop use. They have the same electrical requirments and rules. I dealt with these precise issuse for over two decades and would always meet with the architects when they were designing a new building for the machines I installed and serviced that drew up to 70 amps on two circuits. I also dealt closely with the power company over these issues. The NEC in the US and the NEC in Canada are nearly identical with only a few areas where the Canadian code is slightly tighter. I always carried my code book with me.

                              When you install that in a HOUSE, it is a "branch circuit", end of story. Nothing about welders etc applies, unless it is WIRED TO a welder.
                              Funny thing about that welder receptacle. You can't plug much else into it. The story is that the OP is perfectly within code and safe practice to use that cable as an extension cord for his welder. Period.
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