An electrical pigtail is a single piece of electrical wire that is used to connect two or more wires. This wire must be rated for the amperage of the circuit it is being installed into. Often, electrical pigtails are made using scrap or leftover wires from the project being worked on. Because of their simple definition and flexibility, electrical pigtails are used in a variety of settings.
In designing an electrical system, pigtail connections can be useful when multiple wires need to connect to a single device. According to About.com, this can be especially problematic when boxes have multiple cables that cannot be connected to a single terminal. One of the most popular ways to resolve this problem is to connect the wires with a pigtail. This groups the cables together so that it is possible to connect them to a single terminal.
According to the National Electric Code, an electrical pigtail must have at least 6 inches of wire for safety purposes. Many builders and electrical system designers pick out specific colors for pigtails and the wires they are connecting to the terminals to avoid confusion. Even though electrical pigtails can be made of scrap or leftover wire, they still need to be properly marked to keep the system safe.