Impact voltages and currents, which occur in illumination applications from time to time, may force the contactor. It has been classified in terms of type
behavior and closing-breaking operation for selection. While contactor is selected for illumination circuits, important factors are bulb type, connection, whether there is compensation or not, start-up and operating current and power factor. While the contactor is loaded up to 15 times of the lamp rated current during closing in filament lamps, breaking current is equal to rated current. Compensation is very important in discharge and
florescent lamps. In high pressure mercury vapor lamps, a current occurs at two times of the operating current during pre-heating period (approximately 5 minutes).
This regime period is about 10 minutes in halogen lamps and sodium vapor lamps