Circuit interrupter with improved adjustable trip unit

An adjustable trip unit adapted for use with a circuit interrupter and associated sensing means to cause the circuit interrupter to trip upon detection of predetermined electrical characteristics on a circuit passing therethrough, said adjustable trip unit comprising:

• output means adapted for connection to the shunt trip device of the associated circuit interrupter;
• input means adapted for connection to the associated sensing means;
• a housing;
• electronic circuitry disposed in said housing and connected to said input and output means for generating a trip signal upon detection of a predetermined set of electrical parameter values on a circuit through the associated breaker;
• and means for specifying said set of electrical parameter values;
• said specifying means comprising a plurality of first connecting members mounted within said housing and electrically connected to a plurality of components of said electronic circuitry, a removable shorting plug comprising a plurality of second connecting members cooperating with said first connecting members to form electrical contact therebetween and having at least two of said second connecting members in direct electrical connection to each other, the number of said first connecting members being sufficiently greater than the number of said second connecting members such that said shorting plug may be inserted into any of a plurality of positions in said trip unit to selectively connect certain of said circuit components into said electronic circuitry, whereby said set of electrical parameter values are specified.