View Full Version : 230v extension cord
10-06-2006, 10:10 PM
I need to make a extension cord for a Hobart 210 mig. Im using 50 amp plugs. How long of a cord can I make and what gauge wire should I use?
10-06-2006, 10:57 PM
I haven't done a bunch of research and math on the 210 but I'm thinking miller with it's sweet duty cycle at 130 amps will do fine with a 12awg of a reasonable length (50±ft). That will still keep within the NEC's fudge factor chart at 160 amps and a 60% duty cycle.
If "long" to you is 100 ft or so and you plan on running it high and hot I'd think about 10awg. I like the 10awg because it a no loss, no worry arrangement. But for longer cords it can get pricey.
10-07-2006, 07:25 AM
I was needing about 30-35'. So I guess a 12awg should probably serve my purpose. Thanks for the reply Sandy.
10-07-2006, 09:46 AM
I would not use anything less than 8 awg. 12 is rated for 20 amps max, 10 is rated at 30 amps max. your welder will be pulling between 25 to 30 amps, and *** the distance increase so does the wire size. you will probably melt your ext. cord if you go with 12.
10-10-2006, 02:12 PM
The 12ga = 20a and 10ga = 30a is NEC article 240.4(D) and only really applies to regular branch circuit wiring. Article 240.4(G) states that conductor sizing for welders is covered by Article 630 instead. Most welders come from the factory with only 12 or 10ga wiring of their own.
That is not to say that conductors need not be increased due to increased length but the poster specified only 30 feet or so, so not a big deal really.
Here is how you figure it per Article 630:
Welder input=25a @ 230v
Duty cycle correction factor in Art 630 40% = .63 times rated current
Therefore conductor ampacity required equals 16a. You could use 14ga and still be legal, (not overheating the wires) however it would not be a good idea. Voltage drop would probably be a problem.
As for me, I would use 10ga for any extension cord, that way if you wanted to use it for a more demanding process (such as stick) your cord would be good for that too.
10-10-2006, 02:38 PM
I would use #12 if I had to buy the wire and knew I'd never need the wire for anything else. You may also find that you need to double the #12 to get a secure clamp with the 50A connectors and plugs.
bkfran69, electrical requirements are different for welding machines with limiting duty cycles. There is no way for an IM210 to draw enough power for enough time to even get a #12 warm to the touch.
10-13-2006, 09:42 PM
Thanks for everyones replies. I made a 50' long cord using 10 ga. I figured a few dollars more for the 10 ga versus 12 ga was worth the money.
10-13-2006, 10:35 PM
Yeah for 50' the voltage drop might become significant, and it is more "future-proof" than 12ga for a more powerful machine, etc. also easier to terminate the wires.
10-14-2006, 08:29 AM
I am running a Millermatic 210, it draws about 28 amps at 230V.
I worried over this for some time and decided to " do it right " from the outset.
I needed two wire runs, about 45 feet from breaker box to an outlet on the outside of the house. After that another 60 feet or so from that outlet to the shed where the MM210 was to be housed and used.
It was pricey, but I bit the bullet and used 8 ga for the entire run. 8/3 Romex from breaker to outlet. I made a 75 foot extension cord from 8/3 SO rubber cable to go from the outlet to the welder.
Call me 'old school' but I believe that if you are gonna send 28 amps down a conductor, that conductor better be able to handle 28 amps. I realized there is a " fudge factor " that takes into account a welder and it's " duty cycle ". Lets be realistic, if you are wiring a " WXY " welder today, tomorrow you may upgrade to an " XYZ " welder tomorrow and that upgrade may well require a heavier wire. Not only would you have to spend more to buy new wire all over again, but the time involved in rewiring.
In reality I should have run 6ga from the breaker to the outlet, after all it is a 50 amp outlet.
Overkill?? Perhaps but I live out in the sticks so to speak and my biggest concern here is a house/building fire. Wiring is one place I don't scrimp. But damn it was expensive running the circuit for the 210.
Just my .02 cents worth.
10-14-2006, 10:08 AM
Similar to my other post, I agree with running 8ga to the outlet, 6 is probably overkill but not too much of a nuisance because you never have to grab it and move it around. However 10ga is capable of running 28A all day long and your welder draws much less than that when the duty cycle is figured in so an 8ga SO cord is just a waste of money and a big heavy thing to drag around if it is not necessary for a particular machine.
10-15-2006, 08:03 AM
Im only using the 10 ga extension occassionally when I need to be further than 15' from my outlet. The majority of my welding will be done close to the outlet which is 3' from the panel and ran with 8 ga. I only need the 10 ga extension when welding something that requires me to be further than 15' from the outlet. Sometimes overkill is liking buying a Ferarri or marrying a Nun, your getting something you cant use.
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