Pigtail connections are very handy if you have to connect multiple circuit wires to a device such as an outlet receptacle or light fixture. Making electrical connections to a device in an electrical box is easy if there is only one cable entering the box—you simply attach each circuit wire to a corresponding screw terminal on the device. But it is more complicated if the device needs to be connected to two or more circuit wires. Connecting them all under one screw terminal isn’t an option and should never be attempted. The recommended installation method is to connect the circuit wires to the device using a short additional wire, known as a pigtail.
Pigtails are also useful if you need to extend the length of a circuit wire that is too short. If a circuit wire is too short to easily connect to a device, adding a pigtail extension can lengthen the wire enough to make the connection.
It is important that the pigtail wires match the wire gauge of the circuit wires. This ensures that the pigtail can handle the amperage carried by the electrical circuit.
How a Pigtail Works
Pigtailing is typically a technique that is used when making other electrical repairs and replacements—not as a standalone project. Make sure you understand the overall requirements of the project when you are making pigtail connections.
A pigtail wire is a short length of wire that connects at one end to a screw terminal on an electrical device, with the other end joined to circuit wires with a wire connector (wire nut). The most common application is when grounding a switch or receptacle, where green grounding pigtails are used to link the metal box and the device to the circuit grounding wires.
Many electricians use the pigtailing method for connecting hot and neutral wires, even when there are two screw terminals available to attach the circuit wires. The advantage of this is that power will continue to flow to the rest of the circuit should a problem develop in the device. By contrast, when the ingoing and outgoing circuit wires are both connected to screw terminals on the device, a breakdown in that device will halt current flow to all devices downstream on the circuit.
There are other applications for pigtails. For example, where a wall switch needs to control two or more light fixtures fed by different cables leading from the switch box, a short black pigtail wire is used to connect the screw terminal on the switch to the hot wires leading to the light fixtures. This method links the switch to both outgoing hot wires in a code-approved manner.
The National Electric Code requires that a pigtail wire be at least 6 inches long. Electricians often cut their own pigtail wires from scrap wire they have on hand, but green grounding pigtails are also available with pre-attached grounding screws at one end for connection to metal electrical boxes.
When making a pigtail, choose a scrap of wire with insulation that is the same color as the circuit wires you are connecting: white pigtails when connecting to neutral wires, red or black when connecting to hot wires, green or bare copper when connecting to grounding wires.
Equipment / Tools
- Circuit tester
- Combination tool or wire stripper
- Needle-nose pliers
- Scrap pieces of wire
- Wire connectors (either traditional wire nuts or push-fit connectors will work)
Make Sure Power Is Shut Off
As with any electrical repair installation, always make sure that the circuit power has been turned off before connecting a pigtail. Use a circuit tester to verify that the power is off before proceeding. A non-contact circuit tester provides an easy way to test for power before you touch any wires.
Make the Pigtail Wire
Using a combination tool or wire cutters, cut a piece of scrap wire 6 to 8 inches long, the same color and wire gauge as the circuit wires. Strip about 3/4 inch of insulation from each end of the wire, using a combination tool or wire stripper. Some devices, including switches and outlet receptacles, may have a strip gauge embossed on the side of the device to show precisely how much insulation to strip from the wires.
Connect the Pigtail to the Device
Loop the bare wire at one end of the pigtail around the screw terminal on the device in a clockwise direction, using needle-nose pliers. Tight the screw terminal down to secure the wire loop. The loop of wire should fit tightly around the screw shaft, with no copper wire exposed.
- Note: It's best NOT to use the push-in wire connection feature on receptacles and switches, as these tend to be less secure than screw terminal connections. Professionals rarely use the push-in connections, for this reason.
Connect the Pigtail to the Circuit Wire
At the other end of the pigtail, connected the bare end to the circuit wires, using a wire nut or other approved wire connector. Make sure no bare copper wire is exposed. Tug on the wires to make sure they are secure.
If you are connecting a green grounding pigtail to a metal electrical box, thread the green grounding screw attached to the pigtail into the threaded screw opening in the back of the electrical box. The free end of the grounding pigtail attaches to the other grounding wires with a wire connector. When metal boxes are used, there may be two grounding pigtails: one attached to the metal box, and one attached to the device, with the free ends of both pigtails joined to the circuit grounding wires using a wire connector. With plastic electrical boxes, there will be only a single grounding pigtail linking the circuit grounding wires to the device.
Complete the Work
Once all wire connections are complete, tuck the wires back into the electrical box, secure the device to the box, and mount the cover plate. Turn on the power and test the operation of the device.