While I'm only a PPL, I do seem to know more about electrics than some posters on here, so I feel I should point out some items: Circuit Breakers and fuses that are away from the device being protected will only respond to an electrical overload - an overheating boiler, oven, whatever, would only have its circuit interrupted by a thermal device on the thing itself, not by an overcuttent breaker in a panel somewhere else. An overheating "heater" draws roughly the same current as one that's working normally, so nothing in the electrical system will "notice" the problem. Any heating device should have thermal overload protection, and if it turns out that something in the galley had been left on and resulted in this fire, then the thermal cutout must have malfunctioned. A friend of mine used to work in a domestic electrical appliance test laboratory, and they test thermal runaway to prove that the cutout will do the job, and also do "special" tests where the thermal cutout is disabled, to find out what happens then. (Anything from melting the element or the wiring to it, so disconnecting the circuit, to exploding and showing plastic everywhere!). I inadvertently tested my own automatic electric kettle recently, by leaving the lid open so the steam-sensor didn't work. Came back later to find damp wallpaper for the top three feet of the walls, and the kettle empty and turned off by its thermal trip. If a £15 kettle does this, £thousands of aircraft galley equipment will (should) too!