1. A THERMOMOTIVE CIRCUIT BREAKER COMPRISING, IN COMBINATION, A SNAP ACTION ELEMENT NORMALLY CONSTRAINED TO ASSUME A PRE-SET RESTORED POSITION; A RELATIVELY ELONGATED HEAT EXPANSIBLE ELECTRIC RESISTANCE ELEMENT OPERATIVELY ASSOCIATED WITH SAID SNAP ACTION ELEMENT AND, IN ITS COLD AND CONTRACTED STATE, CONSTRAINING SAID SNAP ACTION ELEMENT SNAPPED TO A STRESS-DEFORMED POSITION, SAID SNAP ACTION ELEMENT SNAPPING TO ITS RESTORED POSITION UPON PRE-SET EXPANSION OF SAID RESISTANCE ELEMENT; A PAIR OF LOAD CIRCUIT CONTROLLING CONTACTS OPERATIVELY ASSOCIATED WITH SAID SNAP ACTION ELEMENT AND IN ELECTRIC CIRCUIT CONNECTION WITH SAID RESISTANCE ELEMENT, SAID CONTACTS BEING CLOSED IN ONE POSITION OF SAID SNAP ACTION ELEMENT AND CONTROLLING THE FLOW OF HEATING CURRENT THROUGH SAID RESISTANCE ELEMENT; THERMOMOTIVE ACTUATED SHORTING MEANS HAVING A FIXED END ELECTRICALLY CONNECTED TO AN END OF SAID RESISTANCE ELEMENT AND HAVING A FREE PORTION MOVABLE ALONG SAID RESISTANCE ELEMENT IN SLIDING CONTACT THEREWITH TO SHORT OUT SAID RESISTANCE ELEMENT IN PROPORTION TO HEATING OF SAID SHORTING MEANS; AND AN ELECTRIC HEATER FOR SAID SHORTING MEANS IN SHUNT WITH SAID CONTACTS AND SUBJECTED TO ANY POTENTIAL DROP ACROSS SAID CONTACTS.