Terminal Block Wire Connector PCB Mount 5mm Pitch 2 Pin Screw Terminal Block Connector YX-128 Connector A terminal block is a modular, insulated block that secures two or more wires together. Factories use terminal blocks to secure and/or terminate wires.In their most basic form, terminal blocks consist of several individual terminals which are arranged in a long strip. The terminal block is most useful for connecting wiring to ground.