If you want to directly feed the receptacle you must change the supply breaker to 50A. The 60A breaker is illegal on a NEMA 6-50 receptacle. Option 1: Change the breaker to 50A ($12) Your 30A Paragon kiln would work better on a 40A circuit, but we presume that TUV (an alternative to UL) certified it also for a 50A circuit, as that is plausible for them to do. Since the units ship with NEMA 6-50 receptacles, they need 50A circuits. The only exception is that there is no NEMA specification for a 40A socket, so 50A sockets are used on 40A circuits. However, socket sizes must match the circuit breaker, unless an exception is specified in NEC 210.21.

Annoyingly, nothing about this is mentioned on the equipment nameplates, and it would help a lot if it said 'Circuit breaker: 50A'.Īs things are, the kiln manufacturer is resting entirely on their admonishment not to change the plug, and the assumption that NEMA 6-50 receptacles are wired with 50A breakers (which is not a valid assumption at all, see below.) That would mean kilns would be at 100% nameplate ampacity for less than 3 hours, and then would fall below 80% nameplate, which means the 125% derate isn't really applicable. That's a short startup (<3h) so it behaves like inrush. Kilns aren't flat, though - usually kanthal elements and those change resistance about 1.6x from cold to operating temperature. I would agree that ordinarily, a 125% derate would need to be applied by default. We see a lot of blatant 'ignoring of Code' among kiln and welder folks, and your current sockets are no exception.

Neutral can be energized and float at 120V under a number of common wire failures - that's why we put insulation on it. In sub panels and outbuildings, there's a big difference. The difference is that the neutral pin on a NEMA 10 socket is wired to the neutral of the house, not the ground. The manufacturers insist not to do that, and Paragon voids the warranty when you do. They really should be using the NEMA 6 type receptacle. Usually this involves cutting off the correct socket and then putting 'Amateur's choice' of socket, typically based on the existing sockets they have in their home for dryers and whatnot. Several communities, such as welders and kiln people, have 'adopted' the defective NEMA 10 as 'their private socket' even thought it is wrong. The plugs and sockets are still sold, strictly for direct replacement of a broken plug or socket. Finally around 30 years ago, NEC 'put its foot down' and banned NEMA 10 absolutely. Appliance manufacturers and builders dragged their feet on switching to NEMA 14. Unfortunately, this permission was wildly abused. It was expected these would be wired with '/3 w/ground' cables, so the socket could be changed to NEMA 14 in the future. New wire was required to be grounded, but the old 3-prong NEMA 10 connector could be used for awhile to accommodate dryers and ranges with the old cords. However there was still a large inventory of ungrounded 30-50A cabling in the manufacturing pipeline, so an exception was made to allow ungrounded wiring for dryers and ranges only until wire stocks ran out.

Safety grounding became mandatory in the 1960s (NEC 1966). The kiln manufactures supply NEMA 6 receptacles appropriate to the unit, so clearly, 'monkey business' has gone on here. It is obsolete and dangerous, and does not contain a ground wire. The plug, as provided on the new-to-you equipment, is a 'NEMA 10-30' type.

240 volt plug in