To prevent overloading the starter, do not select heater(s) for a motor of larger rating than the maximum given on the nameplate for the starter.

For continuous rated motors, with a service factor of 1.15 to 1.25, select the heater with maximum motor amperes equal to or immediately greater than the motor full-load current (provides a maximum of 125% protection). For continuous rated motors with no service factor, multiply the full-load current of the motor by 0.90 and use this value to select the heater