Match wire colors — Match each pigtail wire to the corresponding vehicle wire by color. Splice the wires — Use heat-shrink butt connectors for a waterproof, vibration-resistant connection. Insert one wire from each end and crimp. Wiring a pigtail involves stripping the ends of your hot, neutral, or ground wires, twisting them together with a lead wire using a UL-listed wire nut, and securing that single lead to the outlet or switch. This method is employed when multiple wires, such as the circuit's incoming and outgoing hot wires, need to connect to a device like an outlet or. But remember not to strip one end if you plan to use a pigtail or nylon closed-end connector.