I did not have a 220v 50 amp power outlet for my welder to plug into. But I do have a 220v 30 amp dryer outlet. So after some research I made a welder to dryer plug conversion and extension cord.
Let me say right off, I am not recommending you do this, and I know it is not exactly the right thing to do. I am just showing you what I did.
The correct thing to do would be to wire in a seperate 220volt 50 amp plug for my welder to plug into. But I already had the dryer plug and this just worked out to be the easiest solution.
My dryer outlet is designed for a maximum of 30 amps at 220volts. My welder can draw a maximum of 50 amps at 220 volts. But I also know that for the thickness of steel that I am normally going to be welding I will not be drawing anywhere near as much amperage as the maximum, and in most cases well below 30 amps.
Also, my dryer outlet is about one foot away from my main power box. That means that I actually have over 250 volts coming in to that outlet when I tested it (no voltage drop because of distance). So that means I will be drawing less amperage for my needs (although I will see a drop in voltage because of the extension cord.)
So I figure worst case senario my welder trys to draw over 30 amps and my circuit breaker pops.
So, I went to Lowe's and bought 15 feet of 3/10 power cord that was rated for 30 amps. I also bought the two ends, the male that plugs into the dryer outlet, and the correct female for the welder. I made the cord this long to get my welder outside with some freedom. But shorter would be better because of the voltage drop over distance.
It was quick and easy to put together and the parts cost about $50. I will let you know how it works out.
Here are some great guides on the web that I read to do this: