The following specification describes a circuit breaker enclosure having a cover, which is latched closed by spring biased latch handles. The handles and cover move in response to gas pressure for relieving the pressure generated on tripping of the circuit breaker. The latch handles are arranged to point outwardly of the enclosure, when open, to provide a clear visual indication of their being open. The circuit breaker handle and enclosure handle are directly engaged with a common pivot pin for synchronous movement to enable the enclosure handle to indicate the trip condition of the breaker. When the cover is open, the handles are interlocked against movement to an ON position by a biased pivotable interlock plate. The cover in turn is latched closed through the interlock plate and a breaker handle plate, when the circuit breaker enclosure handles are in the ON position. A pair of spaced edge projections on the enclosure wall engage the cover sealing gasket to avoid a permanent compression set in the gasket.

An operator is provided for a molded-case circuit breaker of the type in a motor controller where the circuit breaker is removably mounted on a pan brace which is held in place by a pan latch. The operator mounts on the breaker for opening and closing the breaker and for providing three interlocks. One interlock prevents withdrawal or insertion of the breaker with the operator handle in the "on" position. A second interlock prohibits closing or opening the control door except when the handle is off and a third interlock locks the operator handle in "off" position.

Switch apparatus is disclosed. The switch apparatus has an enclosure, having a openable cover, a switch disposed within the enclosure, a handle in operative communication with the switch, a spring in biasing communication with the handle, and interlocking members. The interlocking members, the handle, the biasing spring and the switch having positions relative to each other such that the interlocking members lock the cover in a closed position in response to the handle being biased toward an OFF position, and the switch contacts being closed. Further disclosed is a method for unlocking a closed cover of a switch apparatus. A spring biased handle is changed to an OFF biased position from an ON biased position passing through a non-biased position. Subsequent thereto, a switch being changed from a closed circuit to an open circuit position. Subsequent thereto, interlocking members are changed from an interlocked to a non-interlocked position.

A trip indicator is for a circuit breaker having a housing including first and second openings, separable contacts and an operating mechanism having an operating handle protruding from the first opening. The trip indicator includes a one-piece flag member with a first end having a trip flag and a second end with first and second integral legs. The first leg biases the trip flag away from the second opening when the separable contacts are not tripped open, and includes a latching portion to maintain the flag in a viewable position to indicate the trip condition regardless of the operating mechanism position. The second leg is disposed proximate first leg and biases the operating handle toward the OFF position, thereby assisting the handle to move from the ON position in response to the trip condition.