Abstract: An undervoltage trip coil and armature, with a pivotal member biased against and riding on the latch pin of the armature to sense its position. On occurrence of a low voltage condition, a trip lever causes the latch mechanism of the breaker to trip. The pivotal member then interferes with the latch and prevents reset. The undervoltage trip coil is normally energized to normally attract the undervoltage armature. On occurrence of a specified undervoltage condition the armature releases causing the trip lever to trip the latch mechanism and allowing the pivotal member to interfere with the latch of the breaker. During such condition, the breaker cannot be reset until the armature is attracted to the undervoltage coil under proper voltage condition.

Abstract: A trench duct system of the type embedded in concrete floors or the like is provided for use in the distribution of electrical power, service and/or communication cables and wiring throughout a building. The system includes a plurality of trench duct sections which are interconnected to form a predetermined distribution layout. Each section of duct includes a cover plate which is removably supported by a pair of vertically adjustable side rails. The length of the cover plate and the length of each supporting side rail may or may not be the same and will depend upon the particular layout. The exposed surface of the cover plate is flush with the plane of the finished floor. Adjoining side rails, when in angular relation to one another, are interconnected by coupling members or connectors which maintain the continuity and stability of the system.

Abstract: A circuit breaker of a medium voltage roll-in type is connected to an external control system by a plug and associated conductor line. The plug has a handle that is screwed into position to retain the plug in place and to compress a cable spring connected to a flexible cable enclosed in a tube. The compression of the cable spring enables a lever spring, acting oppositely to the cable spring, to move a lever attached to the cable. The lever is connected to move a trip latch that connects to a latch mechanism that opens and prevents closing of the circuit breaker.