Knowing the different types and uses of electrical wire joints is critical to home repair and electrical maintenance. Joining wires incorrectly or without proper insulation can make the joint overheat, resulting in a potentially deadly fire.
To complete any electrical joint, the practitioner must seal the exposed wires with electrical tape or another type of insulation. There are many types of electrical joints, but several are considered fundamental archetypes. These types of joints include the Western Union splice, tap splice and fixture splice.
Western Union Splice
The Western Union joint is relatively simple and is one of the most common types of joints. This type of joint is used to connect two of the same conductor — repairing a severed wire, for example.
To make a Western Union splice, strip 5 inches of insulation from both conductors. Hold them in an "X" shape, leaving 1 or 2 inches of exposed wire for each conductor above the intersection. Wrap one of the exposed wires around the base of the other, then do the same with the remaining wire and conductor.
A tap splice connects a loose wire to a conductor in a perpendicular shape. This joint resembles a "T" shape, with the connecting wire intersecting the running one. Tap splices allow loose wires to tap the electrical flow of an active wire.
A tap splice requires you to strip 4 inches of insulation from the connecting cord, and 2 inches from the running wire. Hold the two together like a "T" and wrap the exposed wire of the connecting cord around the running wire once. Continue to wrap the wire in the opposite direction of the first coil. This results in one loop on one side of the "T" intersection, with the remaining loops (at least five) on the other side.
A fixture splice is mostly used to connect different-sized conductors, particularly those in electrical fixtures. This type of splice requires a pair of pliers or a similar tool.
To fashion a fixture splice, remove 4 to 5 inches of insulation from both of the wires. Clean them by scraping residue and remaining insulation from the conductor. Hold one of the exposed wires right at the base of the other. Roughly half of the exposed conductor should be on each side of the intersection. Grasp the intersection with the pliers and turn both wires simultaneously. Bend the coil toward the wires to complete the joint.