The VOLTAGE RATING of a switch is the maximum voltage the switch is designed to control. A
voltage higher than the voltage rating may be able to "jump" the open contacts of the switch.
The CURRENT RATING of a switch is the maximum current the switch is designed to carry; it is
dependent on the voltage rating. Any current higher than the current rating may cause the contacts of the
switch to melt and "weld" together.
The contacts of a switch can be checked with an ohmmeter if power is removed or with a voltmeter
if power is applied to the switch. To check a switch, the actuator should be checked for smooth and
correct operation, the terminals should be checked for evidence of corrosion, and the physical condition
of the switch should be determined. If a substitute switch must be used to replace a faulty switch, the
substitute must have all of the following:
At least the same number of poles, throws, and positions; the same number of breaks and an identical
configuration in regard to momentary and locked positions; and a voltage and current rating equal to or
higher than the original switch. In addition, the substitute must be of a physical size compatible with the
mounting, and must have the same type actuator as the original switch.