larry cad wrote:
I don't agree with you. No reason why the 50 amp receptacle cannot be wired from a 30 amp circuit. I will concede IF you can point out the specific code section where this is stated. Typical residential duplex receptacles come in 15 and 20 amp configurations and are typically and legally used in both 15 and 20 amp circuits.
See 210.20B(3): "Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.20(B)(3) ....", followed by a few exceptions that would not apply.
The table says that for 30A circuits, only 30A receptacles are permitted. (For 20A circuits, either 15 or 20A receptacles are permitted. For 15A circuits, though, 20A receptacles are not permitted.)
I do agree that there is no immediate safety issue with putting a 50A receptacle on a 30A circuit; it's obviously more than capable of handling the current that it could carry. I also don't claim that the code is entirely self-evident or perfectly logical. Presumably the idea is to prevent excessive tripping of breakers or running the undersized circuit at the very edge of its capacity all the time or something similar (and maybe also to encourage the makers of equipment to provide appropriately sized power cords and plugs, rather than oversizing them for "convenience" or other reasons).
