Time to pipe up
Kiln failures have brought down many studios and quite a few homes (including ceramic artists). But probably not as many homes as toaster failures. A good rule is to treat your kiln as a pot belly stove. Pot belly stove surfaces are known to get up to 700 deg. Check local codes for this, usually if you make sure that there is 12 to 18 inches of air space around the kiln and plenty of space above and that it sits on a fire proof space you should be ok. Ceramic tile on top of plywood table is not fire proof. If the kiln fails it can transfer enough heat to start the plywood smoldering. If the kiln is sitting on bricks with an air space before the tile this is better. (Some kilns have that airspace built in).
Wiring (I cannot express this enough) must be the proper size for your kiln. Just because you are plugged into a circuit with the right size breaker does not mean that the wire going to your outlet is the right size. The breaker is set up for total load on that circuit, IE if you have a 20 amp breaker; this is the total load for that circuit. When the electrician builds it they will start out from the breaker box with wire designed to handle 20 amps and as he splits the load up ( to outlets and lights) he will use smaller and smaller wire, to the point that he may be down to 10 amp wire at the last outlet. A dedicated line for you kiln is always safest. The wire is like a fuse, if you over work it, it will fail. You cannot depend on your breaker to save you. These can fail too. Electrical failures are a major cause of house fires.
What kind of controller you use is important too. Does it have any fail safes such as what happens if there is a thermocouple failure. Will it shut off or run wild. Newer ones should shut off. Also, do you really need to ramp down. My bead kiln is an old Norman kiln really well insulated. I built the controller myself, using a set point controller with mercury switches. This holds temp forever. When I finish at night I let it sit for 15 to 20 min. and just shut it off. This works so well that 8 hours latter it is still 200 deg or so (my annealing point is 925).
Test your kiln, run it up to your annealing point, let it soak for an hour. This is to make sure that you have soaked all the insulation to saturation point, then shut it of and see how long it takes to get to 200 deg or so.
A little background: I am a journyman lineman, have been for almost 20 years, and work for a power company. I am the one who comes out and fixes the power lines (sometime in ungodly weather). I am also the first responder to house fires. To kill the electric so the fireman are safe to put out the fire.
George
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