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High Speed Ground Switches Southern States automatic high speed ground switches, also sometimes called fault-initiating switches, provide an economical alternative for circuit protection in applications that would otherwise require costly circuit breakers. One of the most common applications of the high speed ground switch is to provide protection of power transformers in circuits having enough impedance to limit the low side fault currents to values below the trip settings of source breakers. The system relays signal the high speed ground switch to close, imposing a deliberate single phase fault to ground on the high side of the power transformer which in turn causes the source breaker to open, clearing the fault. Another popular application for the high speed ground switch is in backup protection for a power transformer as part of a circuit breaker failure scheme or a circuit switcher failure scheme. If a fault occurs and the power transformer's main protective device (either a circuit breaker or a circuit switcher) fails to successfully operate to clear the fault within a defined period of time the high speed ground switch is signaled by system relays to close, imposing a deliberate single phase fault to ground on the high side of the transformer and causing a remote circuit breaker to trip, clearing the fault. High speed ground switches can be furnished as stand-alone devices or can be attached to a hookstick operated switch or to a single phase of a group operated switch. Installing high speed ground switches on the hinge end of hookstick operated switches or to the hinge end of a single phase of a group operated switch is increasing in popularity as this combination device allows you to test operate the ground switch during initial installation and during routine maintenance without imposing a fault on the system as the switch the high speed ground switch is attached to can be opened, isolating the high speed ground switch from the system. After test operation is completed, the high speed ground switch is left in the open position and the switch it is mounted on is closed, readying the high speed ground switch to perform its function. http://www.southernstatesllc.com/product_categories/41/products/11-Ground-SwitchesRead less