What Size Wire for Extension

[kidder]

I just got a Lincoln AC-225 and everything I read about wiring for 50 amps says to use #4 AWG. But there is no way in the world the plug out the welder is #4. So id like to know what size should I use for an extension cord. I'm going to put a 50 amp breaker in my panel and a short run to a sub-panel for an outlet.

[migman]

ayou mean that the wire coming out of the machine isnt # 4 right? if that is what you mean then that is because it is only a couple feet long which makes all the difference. how long of a cord are you making, that would determine the size.

[kidder]

Yeah not #4 out the machine. Not a very long extension, down the wall and some wiggle room, maybe 10 foot.

[migman]

i have a twenty foot extension and i used 8/3 but you could probably get away with 10/3 or maybe even 12/3. how many amps does your machine draw?

[Patriot Performance]

Some 8/3 will do you just fine for an outlet.

[redfish_joe]

Check this out for your extension cord.

http://www.elec-toolbox.com/calculators/voltdrop.htm

[jrfv]

I have a 225 AC/DC machine that I have used for many years. It came with a 6 foot cord of 10 gauge wire and required a 50 amp breaker. I needed to weld on my boat trailer and the only way to reach it at that time was to add a 30+ foot piece of 10 gauge extension cord plus a 50 amp dryer cord that fit my dryer receptacle. 10 gauge is only rated for 30 amps. Using 10 gauge for 50 amps is a fire hazard! IF the wire is covered by something flammable, or coiled up so it can't disperse heat.

That said, I have never had any problem at all with this arrangement. And after I am finished welding I always unplug my welders.

With my 225 AC/DC I have never used rods bigger than 1/8 inch so I think the most amps I ever use is about 120 or so. Usually its around 100. I'll bet this set up never draws more than about 25 amps unless I stick a rod. Wire ratings are based on continuous current draw. If you use your welder for 60% duty cycle the average heat (amps) load on the wire would only be 30 amps ( .60 X 50 ) even if you run the machine at 100 percent of its rated power and properly follow the cool down period.

The other problem of using a smaller wire (besides heat) is voltage drop. Most machines are rated at 115 volts per leg, or 230 volts. Where I live I have 125+ on each leg. I have to run several water pumps and an ice machine about 250 feet from my breaker panel. The total is about 5 hp, and even with all that my voltage is still above 240 at the motors. However, after a big discussion with the power company rep concerning my neighbors power supply, that is an excessive voltage drop. The limit is 3%, which in this case would be 7.2 volts.

On a stick welder it does not matter, you just turn the amps up 5 and you are good to go. If you have 10 gauge wire try it, if it does not melt the insulation you can save some money and have an easier to use extension cord. Try rolling up a 4/0 gauge aluminum extension cord!

[MAC702]

The Lincoln AC225 has a 20% duty cycle at rated output. An even smaller duty cycle at maximum output, which is the only time you'll pull 50A through it. A #10 extension cord is fine.

There are tens of thousands of these units installed throughout the country with #10 primary wire.

[MAC702]

10 gauge is only rated for 30 amps. Using 10 gauge for 50 amps is a fire hazard! ...
... And after I am finished welding I always unplug my welders.

At appropriate duty cycles, you can use #12 wire for 50A, legally and safely.

Why do you unplug your machines?