This control panel has 15-amp meter and 140-volt meter.   The variac is a 140 volt 10 amp and handles the 900-watt coil well. There are two filters; one 20 amp is for the Neon transformer (high voltage) and one 10 amp is for the sparkgap, just to ensure no noise or voltage spikes gets back into the house AC. The variac is fan cooled to ensure long life. Tab on pictures to the left to enlarge.