As a licensed electrician in Oregon and Washington for over 14 years, hire a professional!!! <img src="/forums/images/graemlins/shame.gif" alt="" />
Please do not be one those statistics and homeless because of a house fire. <img src="/forums/images/graemlins/evil.gif" alt="" />
RobG hit the nail on the head precisely, 240 volt dryer outlets and related wiring are only rated/sized at 30 amps!

Most, not all, of the 240 welders I have worked around and wired for, are 40 or 50 amps. I have seen a few at 30 amps.
If you decide to install an outlet, it is a much wiser investment to have it sized for 50 amps. It is easy to change an outlet and breaker for a smaller amperage, but if you only install for 40 amps and want to go bigger, everything must be replaced to the larger size(ie-pipe, wire, breaker, outlet). Why pay for it twice? <img src="/forums/images/graemlins/shiner.gif" alt="" />
The outlet and ALL related wiring must be rated at least what your nameplate on the welder. Anything less will have safety and performance issues.

I have to agree also on buying quality the first time. I tried to tell my old man not to buy HF grinders, but no- he has gone through 3 and on his 4th, I still have my Milwaukee, the same one, no problems.
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