A multi-pole circuit breaker is provided with a trip bar subassembly including a molded bar having integrally formed bearings defining a pivot axis for the subassembly remote from the bar. The bar also includes an integrally formed projection for releasing a latch of a trip free contact operating mechanism. The subassembly also includes an extension unit of formed sheet metal and an elongated pin pivotally connecting the unit to the bar. The unit includes an elongated main section and links individually connected to overload sensing devices of each pole. The links are spaced along the length of the main section extending transverse to the longitudinal axis thereof with the latter being generally parallel to the pin.