Welder Plug Question

[KWH]

Is there a article in the NEC concerning a cord and plug connected welder where you have a box mounted female plug say 50amp that is protected by a larger breaker you need to label this plug for welder use only, article 210.21 (3) exception 1 mentions exceptions for cord connected welders but I thought I read somewhere you had to label the plug.

 

[JDBrown]

I haven't seen a written requirement for such a receptacle to be labeled "Welder Only", but I wouldn't be surprised to find that AHJs require it anyway. The rationale I've heard goes something along the lines of, "Well, this setup is only allowed for welders. You know that and I know that, but the only way the guy they hire 2 years from now is going to know that is if you label it."