Electro thermal fusible link for use in boiler houses. The electro thermal fusible link is for installing in a position where a fire hazard may occur, e.g. Above a burner, an air heater or boiler. The fire will melt the fusible metal link and interrupt the electrical supply to either a gas valve or an alarm etc. The link consists of a purpose built cast aluminium box with a perforated cover having a temperature sensitive fuse. The unit should be mounted so that the perforated cover faces downwards and the ventilation holes in the back of the box must not be obstructed. The link is electrically rated at 5 amps maximum on 200/250volts, single phase, 50 hertz and melts at 155 deg f (68 deg c). Metal box version approx. 3” x 2” x 1”.