whether he needs a separate disconnecting means depends on the control switch(s) on the kiln. If the control knob has the word "off" on it, it means both legs are disconnected when the switch is turned to off. If it doesn't specifically have that on the knob, then it indicates that the thermostatic switch is only opening one leg and the other leg could remain hot even though the kiln was not heating. If it has a separate power switch meant to disconnect both legs, then no separate disconnecting means is required. My code book is buried somewhere's so I can give you the article number right off. As far as voltage drop, unless it's pretty far,say out in the barn, I wouldn't worry too much. The branch circuit ratings are pretty conservative and at worst, the kiln would just put out less heat. If the manufacturer's name and model are on the kiln, I'll bet an owner's manual could be easily found thru the net or a ceramic dealer that sells kilns.
My big question is: how is this guy going to have any time to run a kiln anyway?...it's going to take all his time to read this thread, hey? Luck, Kizmet