Ultra high voltage, low corona, air edge type earth relay. Peak test ratings up to 300kV and 100 amps continuous current. The device can be operated by solenoid, motor or cylinder, with spring or gravity return. All models have spherical contacts. Some models have an adjustable ball gap when voltage transient limits are required. Units with built-in high voltage discharge resistors are also available with an energy dissipation capacity of 50 to 10,000 ohms. The height of some units can be reduced if the full line to ground voltage is connected only to the top high voltage contact and the other high voltage terminal is operating at or near the ground potential. Line-to-ground voltage can also be increased by adding an edge between the lower high-voltage contact and the ground. Usually mount the base downward.