Patent ID: 7030514

Claim:
A power transfer switch assembly modularly attachable to a service installation, for selectively connecting one of a main power supply and an alternate power supply to a power load comprising: a first power switch including an electro-mechanically-held device for actuating the mechanical switching elements between an ON state and an OFF state, for receiving the main power supply and for coupling the main power supply to the power load in the ON state; a second power switch including an electro-mechanically-held device for actuating the mechanical switching elements between an ON state and an OFF state, for receiving the alternate power supply and for coupling the alternate power supply to the power load in the ON state; a mechanical interlock having a locking actuator mechanically coupled to the first and the second power switches for physically preventing the first power switch and the second power switch from assuming simultaneous ON states, the locking actuator having a pair of L-shaped tabs that are in sliding engagement with the body of the mechanical inter lock; a controller for monitoring the main power supply and switching the first power switch to the OFF state and the second power switch to the ON state when a disturbance in the main power supply is detected, the controller switching the second power switch to the OFF state and the first power switch to the ON state when the main power supply is restored; and, a casing containing the first power switch, the second power switch, the mechanical interlock and the controller, the casing having load terminals and line terminals for connection with a meter socket of the service installation, and line out and line in feed terminals for connection with a watt-hour meter of the service installation, the load terminals being connected to the first and second power switches, the line terminals being connected to the line out feed terminals, and the line in feed terminals being connected to the first power switch.