The voltage required is pre-set manually on the unit to a minimum level determined by the thickness of film of the coating product and its generic type i.e.: PVC, Teflon, FRP or polyethylene. Detailed instructions are set out in the section of the Operator’s Manual marked Recommended Minimum Voltage. It is important to follow these instructions in setting voltages as some surfaces have a much higher dielectric strength than others – consequently offering a high resistance to the conduction of electricity. Applied test voltages should only be sufficient to detect faults, otherwise overstressing of the dielectric strength may occur with possible surface rupturing.