240v/50a Welder Problem.

[abrace]

Yes, you are correct on the exceptions for specific equipment...But I guess it was my mistake for assuming the original question was based on a home Garage/Shop scenario, where the person wasn't that well versed on the specifics of the NEC and would use the most common conductors available such as 6/3 romex... I should have known better than "assume" anything.
I totally agree that in a commercial shop where multiple Welders are used it would make more economic sense to wire them accordingly. In a home shop where one receptacle may be used for a few different pieces of equipment, one 50A receptacle with #6 wire would be able to safely handle them.
My Bad.

Fair enough. Your suggestion will not get anyone killed and there is nothing wrong with it. It is a more expensive way to wire a welder when it may not be required, but if someone isn't completely comfortable understanding the wiring rules for arc welders that allows them to undersize conductors then going with the standard 50A Wire = 50A breaker will work fine and possibly future proof the install.

In my case I have 3 welders that each take a 50A 240V (6-50) receptacle, and the cords on them are short as heck, so I like to have the receptacle near the welder versus using 50A extension cords...so exploiting the rule saved me a bunch of cash...and when properly labeled and understood it is a perfectly safe install.

---Aaron