Abstract: An electric circuit breaker or switch is disclosed having a plug-in connection means with an auxiliary bolt-operated means for enhancing the electrical and mechanical connection between the circuit breaker and a panelboard terminal. A U-shaped terminal clip is mounted in an opening in the circuit breaker case. The terminal clip engages over and frictionally grips a stab terminal on a panelboard to provide an electrical connection. A C-shaped clamp fits over and partially encircles the terminal clip in such a manner that the free ends of the clamp arms project inwardly toward and contact the legs of the terminal clip. A screw, which may be non-conductive, is retained in a bore in the molded case of the circuit breaker, extends into the terminal clip opening and engages a threaded hole in the C-shaped clamp.