Abstract: A fault detector for detecting the occurrence of a rapid pressure rise within electrical equipment. The fault detector has a chamber having an interior, a diaphragm in sealing engagement with the chamber and an aperture providing fluid communication between the interior of the chamber and the external environment of the chamber.

Abstract: A temperature sensor has a heat-sensitive element contained within a chamber, the heat-sensitive element changing from a first configuration to a second configuration at a predetermined temperature, and a biased member biased towards the chamber. The biased member initially is prevented from entering the chamber when the heat-sensitive element is in the first configuration and enters the chamber when the heat-sensitive element is in the second configuration. In some aspects, the first configuration is solid and the second configuration is liquid and a selectively permeable element is provided to allow the heat-sensitive element to exit the chamber in the liquid configuration. An indicator can be provided that has a plurality of feet initially held in a retained configuration by the biased member until the biased member enters the chamber to release the feet for sliding motion of the indicator.