How to Wire a Light Socket
Some Background Information Before Starting: Why It Is Important to Connect Hot and Neutral Wires Correctly
You can attach the wires to a light socket without paying attention to hot and neutral and your socket will probably operate without anything seeming wrong, but the chance of getting a shock when handling the socket – especially while changing the bulb - is higher if you do not use the hot and neutral wires correctly.
Electricity creates a circuit through the bulb by running through the metal tab at the bottom of the socket where the bulb sits, through the bulb, and through the metal threads on the socket where the bulb is screwed in to the socket.
When wired properly, the metal threads of the socket will never be hot to the touch or give you a shock, whether the switch is on or off. When wired incorrectly, the threads or any conductive metal touching the threads - including the outside of the socket or the threads of a light bulb - can give you a shock whether the switch is on or off. Therefore, it is important to follow the instructions for the hot and neutral wires carefully.
Wiring the Socket
- VERY IMPORTANT: Make sure any electrical device being worked on is not connected to electricity. Turn off the circuit breaker, remove the fuse, or unplug the device before starting. If you have any questions about the safety of what you are doing, please contact an electrician rather than doing the job yourself.
- A few simple tools are necessary to complete this process. Clockwise from left you will need a screwdriver (flat head or Phillips head depending on the screws in the socket you are working with), a pair of scissors capable of cutting through soft plastic (for cutting strips of silicone tape and the outer plastic of a jacketed cord, such as pulley cord), a fine pair of fabric scissors (for snipping off the end of the cloth braid), silicone tape (available on our web site) (to bind ends of cloth covered wire to prevent fraying), a retractable knife like a box cutter (for cutting into the outer plastic of a jacketed cord) and a wire stripper with slots that accommodate the gauge of wire you are using. The second picture below shows the slots, labeled by gauge, in the wire stripper.
- Cut the wire to the length you want plus 6 inches.
- Disassemble your socket into its pieces - the cap, the interior, and the shell. The cap is the part where the wire exits the socket; the interior is the part with the screws where you attach the wire and that has the place where the bulb is screwed in; and the shell is the part that attaches to the cap to enclose the interior.
- In our brass sockets there are cardboard insulators in the cap and the shell. Do not discard these pieces - they are intended to put a barrier between metal pieces that could otherwise touch and create risk for shock.
- If you are using a strain relief:
- For a collar strain relief, first remove the set screw and set it aside. (A set screw is a tiny screw in a strain relief or a socket cap that, at the end of the socket application, is screwed in to hold the piece with the set screw to the underlying part.) Then slide the strain relief onto the wire with the threaded portion facing the end of the wire where the socket will go. Wait until the socket is wired and reassembled before screwing the strain relief into the socket cap and replacing the set screw in the strain relief.
- For a screw-top strain relief, unscrew its two parts and feed its outside piece over the wire first with the wider end facing the end of the wire where the socket will be. Then thread the inner section on with side with the shorter length of threading facing the end of the wire where the socket will be. Wait until the socket is wired and reassembled before screwing the inside of the strain relief into the socket cap and then screwing the outside piece over it.
- Next,if you have a cast socket, slide the ring that holds the cap to the shell onto the wire first, oriented with the wider, non-curved side of the ring towards the end of the wire where the socket will go. Our solid and Bakelite sockets don't have this ring, so you would skip that step. For all socket types, first unscrew the socket cap's set screw enough for the end of the screw to not show in the cap's wireway hole. Then slide the socket cap over the wire with the wide opening toward the end of the wire where the socket will go.
Left: example of our pulley cord with cast brass socket cap and metal collar strain relief. Right: example of our twisted wire with Bakelite socket cap and plastic screw-top strain relief.
- Cut an appropriate amount of the cloth braid off the wire. For our twisted wire remove 1" of cloth. For any other of our wires remove 2" of cloth. Unravel the cotton or rayon, snipping it away incrementally using the finest scissors you have. Take care not to cut into the plastic insulation at all. If you do nick the insulation, you will need to cut that part of the wire off and redo the removal of the cloth braid.
- Use a 1.5” length of self-fusing silicone tape to bind the cloth to the wire's plastic insulation. The silicone tape sticks to itself (a little like Saran Wrap) but is not sticky. It will stay on best if you stretch it as you wind it around the wire. Try to keep the taped area as tight and narrow as possible with the tape half covering the cloth and half covering the plastic insulation. This will prevent issues with the wire fitting in the socket and the tape showing out of the socket cap's wireway hole. For our twisted wires, tape each leg of the twist individually.
For jacketed cords like our pulley cord you will now need to remove the plastic jacket, slicing up from the tape with a retractable knife blade like a box cutter or other jacket-cutting tool, taking extreme caution not to cut into the underlying wires' insulation. To help prevent cutting into the underlying wires we recommend exposing the smallest amount of the retractable knife blade as possible that can still cut through the thickness of the jacket. If you do nick the insulation on the underlying wires, you will need to cut that part of the wire off and redo the removal of the cloth braid and the jacket. Cut off the plastic and all interior padding (some paper and/or additional plastic), leaving only the interior wires. Tape over the jagged edge of the cut plastic jacket to keep this section neat.
- For our parallel cords you will need to start to separate the fused hot and neutral wires with a retractable knife blade in the slot in the middle of the wire, taking extreme caution not to cut into either wire, and then pull the two wires apart until you have them separated for ½”. For all wires, strip ½” of the plastic insulation off the ends of each wire, using the slot in the wire stripper's head that matches the gauge of the wire you are using. A wire stripper is the best tool for removing the insulation because it does not cut the copper, just the plastic around the copper. If you end up losing strands of copper, you need to cut the ends off, move the end of the cloth and the jacket if there is one back by ½”, and re-strip the ends so that you have the full amount of copper. You need all the copper to have a secure connection to the socket. Now twist the strands of copper together.
- Tie an underwriter’s knot in the wire. Follow the path of the wires as shown in the picture below to make the knot. The knot helps keep the wires connected to the socket even with some weight applied to the socket. With our twisted wire, the knot should be tied with the part of the wire that has cloth on it. After the knot is tied, the silicone tape will be just beyond the knot.
If you are using a 3-conductor wire, tie the knot using only the black and white wires, ignoring the green wire.
- Make a hook out of the end of the neutral wire. See the chart below for which wire is hot and which is neutral.
|Identifying the Hot, Neutral, and Ground Wires
||*plain (no stripe) wire
||narrow prong/gold screw
||wide prong/silver screw
* This is a Sundial Wire convention. In non-Sundial Wire, the hot wire is black and the neutral white. Sundial Wire uses the stripe/no-stripe convention so that the color of the plastic does not show through the braid. Also in some of our wires there is no striped wire, but a beige wire which is hot and a white wire which is neutral.
- Rest the hook of the wire over the silver screw in the socket, with the hook bending clockwise around the screw. Tighten the screw, making sure to sandwich as much copper as possible under the screw when completely tightened. It helps to keep pushing the wire under the screw as you tighten the screw, using your fingernail or thumbnail or a very small screwdriver if you have no nails. Every time the wire starts to squeeze out from under the screw, push it back under, backing the screw off if you need to. If you screw the screw down very slowly, you should be able to keep pushing the wire under it successfully.
- Repeat the above process with the hot wire and the gold screw.
- Put the socket shell over the socket interior and attach it to the socket cap. For our Bakelite sockets the cap and shell screw together. For our solid brass sockets the cap and shell snap into each other. As noted before, for our cast brass sockets there is a ring that screws over threads on the bottom of the shell and brings the cap and shell together over the interior.
- Screw the collar or the inside section of the screw-top strain relief into the socket cap. If you are using a collar strain relief, screw in the set screw to anchor the collar to the wire. If using a screw-top strain relief, screw the outside piece onto the interior section so that the strain relief grips the wire. For both types of strain relief, now screw in the socket cap's set screw to anchor it to the strain relief.