a cable temperature measurement circuit includes a heating circuit which comprises a series connection of a current generator , the cable to be heated and a high current shunt and a testing circuit which includes a low current generator , the cable and a low current shunt . additional circuit means are provided which generate a signal in response to the relative voltage drops across the cable and across either of the high current or low current shunts . an indicator responses to the signal thus generated to provide a readout showing cable temperature .