Abstract: The invention concerns a solid state trip unit having long time delay, short time delay and ground fault trip circuits. It comprises a metering resistor (40) electrically connected in a series circuit (42) including additionally a power supply (44) for the trip circuits LR, CR and H, and a trip coil (22). A switch (52) connected in parallel with the coil (22) which may be either in an ON-state to shunt the coil (20), or in an OFF-state after a trip signal is delivered from one of the trip circuits, so as to cause an increase of the impedance of the series circuit (42) and the excitation of the trip coil (22). The trip unit can be applied to low-voltage circuit breakers.

Abstract: A rack-mounted electronic equipment module having plug-in normal-service contacts for engagement with the connector panel of a cabinet. The module comprises, preferably on the front edge of the module card, a plurality of aligned test contacts cooperating with a removable plug-in test bar. A single test bar may be provided to test the operation of several modules.