Abstract: A circuit breaker includes a microprocessor-based trip unit and a designator circuit including a plurality of jumper positions. Each jumper position corresponds to one digit of a four digit style number specifying which of a plurality of optional functions and features are incorporated in the specific trip unit. Each jumper position is a multitap voltage divider. Selection of one tap on each of the jumper positions causes a set of four analog voltages to be supplied to the trip unit. An analog-to-digital converter converts the analog voltages to a series of digital representations which are interpreted by the microcomputer as a style number used to command execution of a discrete set of instruction groups, with each instruction group corresponding to one of the optional functions and features.

Abstract: A circuit interrupter is provided with a trip unit removably inserted into the housing of circuit interrupter through the cover thereof. The trip unit is secured to the housing by spring clips mounted therein cooperating with recesses in the enclosure of the trip unit to permit insertion of the trip unit with the cover installed but preventing removal of the trip unit without prior removal of the circuit interrupter cover.

Abstract: Solid state relay system which includes a break-before-make function on both the opening and closing operation thereof is taught. The system may be utilized in conjunction with an "on" delay module or an "off" delay module or with a module that is generally instantaneous in operation.