Abstract: An expendable heating device having a consumable electrode for extending into a bath of molten glass. The apparatus includes an L-shaped refractory holder whose longer leg is adapted to sit on the top of a wall such as that of a feeding extension or doghouse of a tank type glass melting furnace and whose shorter leg projects into the bath of molten glass for forming a protective jacket for the consumable electrode. The long leg of the refractory holder encases a bus bar which projects from the end thereof, the projecting end of the bus bar being adapted to be connected to a source of electrical energy. The bus bar is held in place within the long leg of the holder by a pair of clamping devices.