NEC and NEMA overrated receptacles on 240 V circuits

Perfectly legal, see table 210.24 They don't really make a 40a receptacle so the NEC and NEMA say a 40a circuit can use a 50a. You just have to be sure your breaker reflects the conductor size

| My business sells a product that draws about 32 amps on a 240 V, | single phase circuit. The product is sold with a 6-50 plug attached | to it's cord. In the manufacturers literature, they specify a 40 amp | breaker and 8 gauge wiring for hookup in the customers location. | (Note: The product is UL approved.) | | Obviously, a 6-50 plug requires a 6-50 receptacle. So in the end, the | customer is being directed to install a 6-50 receptacle (good for 50 | amps) on a circuit with a 40 amp breaker and 8 gauge wiring. | | Is this OK? Is it implied that if you install a 50 amp receptacle on | a circuit, that the circuit is good for a 50 amp device? I recognize | that the 40 breaker will protect the 8 gauge wiring if a 50 amp device | is plugged in. However it seems like a bad idea to install a | overrated receptacle on a circuit. Am I over reacting?

Unlike convenience outlets (5-15R and 5-20R, and some might say also

6-15R and 6-20R), higher current outlets generally get used only on dedicated circuits. Would you think of a good reason to ever have two or more 6-50R or 14-50R outlets on the same circuit?

A dedicated circuit branch breaker can provide overcurrent protection not only for the building wiring and receptacle, but also for the cord and internal equipment wiring. The specification for a 40 amp breaker may well mean that the equipment internals are rated only for 40 amps. Why add a 40 amp unit breaker costing a couple hundred dollars extra when the panel branch breaker has to be there anyway? Just put in the dedicated breaker for the correct rating and that's all you need.

Thank you

The ability to use a single portable welder at different locations around a multibay garage?

Bob Weiss N2IXK

I had a garden variety "dryer" plug on my "buzz box" and multiple outlets in the garage for exactly that reason. I couldn't do laundry and weld at the same time but it did allow me to use my welder before I rewired the place.