A standard electric kiln normally requires 220-240 single phase voltage to work properly. It is possible to fire your kiln on a 208 volt source, but firing times may be slower. If your kiln should be wired for 208 volts you cannot use it on 240 volt source.
The coils in your elements should not be so close together that they touch each other.
Your electrical installation for your kiln will be as good as the electrician you use.
When firing allow at least one element groove between every shelf. If your kiln has a blank spacer ring, let at least two element grooves contribute to the heat of the blank space.
When installing wiring for hooking up your kiln, be sure that the proper gauge wire is being used to carry the load. If the proper wire is not used your breaker switch or fuses will go when the kiln heats up to maximum temperatures.
You should always inspect a new kiln when it arrives. Vibration and jarring in shipping sometimes causes elements in the kiln to become dislodged.