These Terminal Blocks are preferred for applications where the connections are subjected to severe vibrations. The wire is crimped to ring/fork type Lug (Ferrule) and is screwed on to flat current bar on the Terminal Block. The fastening nut always remains captive in the hinged plastic carrier. The Hinged Carrier should be lifted to insert the lugs and then snapped back into position. The nut can then be fastened to complete the connection. By the virtue of the hinged design the Terminal Blocks apart from shrouding the live parts, providing IP20 protection, saves considerable time in wiring.