1. A CIRCUIT BREAKER HAVING RELATIVELY MOVABLE CONTACTS AND MEANS RELEASABLE TO EFFECT OPENING OF SAID CONTACTS, A LATCH MECHANISM COMPRISING A LATCH MEMBER ENGAGING AND RELEASABLY RESTRAINING THE RELEASABLE MEANS, A TRIP STRUCTURE SEPARATE FROM THE LATCH MEMBER AND LATCHING THE LATCH MEMBER IN LATCHING POSITION, ELECTROMAGNETIC TRIP MEANS COMPRISING A MAGNETIC MEMBER, AN ARMATURE STRUCTURE OPERABLE UPON SUFFICIENT ENERGIZATION OF THE ELECTROMAGNETIC TRIP MEANS TO ENGAGE AND MOVE THE TRIP STRUC-