Is it safe to fire six 120-volt kilns during a seminar?

It is safe to have six kilns firing at the same time as long as they are each plugged into separate 120-volt circuits that have been properly installed by an electrician. If the center when you are teaching the seminar doesn't have six separate circuits in one room, the kilns may have to be fired in two or more rooms. It would be unsafe to plug two kilns into outlets that are wired to the same circuit. The circuit breaker would trip when you turned on the second kiln, but if the breaker failed for some reason, the circuit wire would overheat.