Abstract: An electrical enclosure lid composed of several elongated members nested in such a way that a tortuous air channel is created between each member. The air channel allows heat generated by internal electrical components, such as large power transformers, to pass out of the lid to facilitate convection cooling of the enclosure. Due to the labyrinthine air channel, flames potentially generated inside the enclosure are hindered from passing outside the enclosure. Drainage holes are included on the sides of the lid to allow water to pass over the lid without entering the enclosure. The design is optimized for harsh environments such as a mining operation where large amounts of power are needed in close proximity to workers. The nesting structure provides strong structural support to protect the enclosure in case of a rock fall or a cave-in.

Abstract: A combination disconnect/reversing switch for use in explosive environments for isolating an electrical power source from a three-phase motor or for reversing the operation of a motor. The disconnect/reversing switch comprises a handle, mounting plate, front insulator plate, mounting flange, front contact holder, moveable contact holder, rear contact holder, and rear contact retainer. The handle actuates the moveable contact holder between open circuit, or load-grounded, (or reverse in the case of a reversing switch) and closed (or forward) positions. The moveable contact holder contains three electrically conductive pin members which engage corresponding electrical contacts on either the front contact holder, corresponding to the open (or reverse in the case of a reversing switch) position, or rear contact holder, corresponding to the closed (or forward) position.