Double break circuit breaker having improved secondary section

Abstract

A circuit breaker includes a first section and a second section with substantially independently operating pairs of contact assemblies in each respective section. In the first section, at least one of the contact assemblies is constructed and arranged to interrupt the current by moving from a normally closed position to a blown-open position and latching with the contact assemblies separated. The second section has a biasing extension spring for biasing the contact assemblies of the second section so as to permit interruption of the current in response to a blow-open force, which causes the contacts to separate only momentarily and then return to a normally closed position. The first and second pairs of contact assemblies separate substantially simultaneously in response to the blow-open force, and only the first section reacts to lower-level over-current conditions. To prevent welding or sticking of the contacts in the second section, a kicker is interposed between the pairs of contact assemblies so as to slightly open the contact assemblies in the second section in response to the contact assemblies of the first section reacting to the lower-level over-current conditions. The circuit breaker is designed to operate using 'Z-axis' mountable components.