To prevent an electric wire from smoking even at abnormal electric load by constituting a driving element with excessive temperature protecting function so that interception beginning temperature can be externally changed, and lowering the interception beginning temperature by a fixed quantity according to the detected temperature.
Driving elements 9, 10, 11 are IPD with overheat intercepting function used for driving the respective ones of load groups 17, 18, 19. Electric wires 13, 14, 15 electrically connect together a control unit 6 and the load groups 17, 18, 19, and they are bundled to constitute wire harness. A temperature sensor 16 and 20 respectively measure the atmospheric temperature of a part of the wire harness exposed to high temperature and the atmospheric temperature of the control unit. Circuits 21, 22, 23 are external circuits for changing the interception temperature of the IPD with overheat intercepting function. By starting overheat interception simultaneously with smoking of the electric wire, electric wire smoking accident can be previously prevented.
YOSHIDA TATSUYA
OKAMOTO CHIKAYUKI
OSAKA ICHIRO
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