With key (included) turn the Earth lock clockwise (Fig 1). Take the Earth cable end connector (not included) and plug into the Earth socket. Figure 1 The Powersafe connectors are mechanically keyed to prevent. Phase 3's Powersafe Sequential Mating Box controls the connection sequence of incoming / outgoing high current cable connections. A paid repair will be provided if the warranty period expires. In this video, the entire power distribution box is removed including electrical connections on the bottom.