Knowing how to pigtail a ground wire is very helpful for many DIY projects. If your wires are too short and uncomfortable to work with, the pigtailing technique comes in handy. Pigtailing simplifies excess wiring by combining wires like ground wires.
In this guide, I will teach you how to pigtail ground connections in metal and electrical boxes, and how to make a perfect pigtail. As an electrician, I have to pigtail ground wires every once in a while and can say it’s pretty easy once you get the hang of it. Below I will provide straightforward explanations with photos to guide you through the process.
In general, to pigtail, a ground connection, first switch off the power supply to the electrical box you are handling. Identify the neutral, ground, and hot wires from the main source cable. Next, wind the ground wire or wires together using pliers. Make sure the wires are firmly twisted together. Snip the sharp end and nest the twisted terminal in a wire cap.
What is a Pigtail Wire Connection?
An electrical pigtail connection is a technique of lengthening wires, or winding together multiple wires; then leaving a conductor that can be connected to other electrical devices such as switches or outlets. Making a pigtail is very easy even for beginners.
Use the following tools to make a pigtail:
- Wire strippers
- Linesman pliers
- Scrap pieces of wires
Use the strippers to remove the insulation coating from the wires. Strip about ½ inch of the insulation. You can then twist the naked ends of the wires before you pigtail them. Finally, nest the twisted terminal in a wire cap. Alternatively, you can use adhesive tape to wrap and insulate the wound section of the pigtailed wire.
How to Ground in Metal Boxes
Before you begin, you should shut down the power. You can pigtail the wires while the power is on if you have enough experience.
Using screws is the most reliable way of grounding metal boxes and light fixture enclosures. But it is not the only grounding technique.
The following are ways you can use to ground a metal box:
Method 1: Using a Green Screw with a Pigtail
- The first thing to do is cut off the power supply to the socket or the metal box.
- Go ahead and identify the ground wire from the main source cable. It is usually green or sometimes yellow.
- Using a wire stripper removes the insulation cover to about ½ inch on the ground wire or wires.
- Use your pliers to twist the pigtail wire and the ground wire together. Snip the sharp edge at the terminal and then insert it into the wire cap.
- If your metal box is in use, secure a green screw in the threaded opening at the back of the metal box.
- Now connect the equipment-grounding cables or pigtails to the screw on the metal box. That way, the metal becomes a part of the grounding system.
- Tighten the connection and then tuck everything back into the metal box. Reinstall the cover and restore the power.
Method 2: Use Ground Clips to Ground the Metal Box
This is an alternative (and approved) method that you can use to ground your metal box conveniently. The clip is a recognized hardware piece, and it works just fine.
- Slide the clip onto the edge of the metal box.
- Ensure that the clip firmly anchors the equipment-grounding conductor against the metal.
Note: Do not fold back bare ground wire to make it touch the inside part of the Romex connector as the cable enters the metal box. That is a big red flag, and you may be fined by electrical inspectors. Additionally, that is not a feasible way of making long-lasting low-impedance grounding.
How to Ground in Plastic Boxes
While metal boxes can be grounded with screws and grounding clips, plastic boxes are grounded differently. It is, however, necessary to tag along the equipment-grounding conductor to the enclosure to ground switches and the receptacles.
The procedure below will help you ground your plastic box:
- Similarly (as compared to the metal boxes), locate the green or yellow wire from the main power cable in the box – the ground wire. You may have several ground wires going to various loads such as the socket and the light fixture. Strip the insulation coating to about ½ inch and twist the ground wires together.
- Now get a bare copper wire or a pigtail and twist it on the ground wire connection with pliers. Insert it in a wire cap. (1)
- Affix the pigtail to the equipment-grounding conductors in the two cables to attach to the grounding screw. That is if there is another cable exiting the box to feed downstream devices.
- Lastly, secure the pigtail on the green screw and gently return everything into the plastic box. Restore the power and check your connection. (2)
The pigtail maintains the grounding continuity even if the downstream devices are removed.
Take a look at some of our related articles below.
- How to connect ground wires together
- How to test PC power supply with multimeter
- What to do with ground wire if no ground
(1) copper – https://www.rsc.org/periodic-table/element/29/copper
(2) Restore the power – https://www.sciencedirect.com/topics/
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