Santon changeover and bypass switches can be supplied using cam, packet or flat-pack switches. Each type has inherent interlocking as no 2 positions can be chosen at the same time. The changeover switches can be either 2 pole or 4 pole, loose or enclosed. There are 3 different types of standard bypass switches each one being 4 pole. The UPS bypass switch incorporates a test position which supplies the UPS and bypass whilst breaking the UPS output.