How to Wire a Plug





Some Background Information Before Starting: Why It’s Important to Connect Hot and Neutral Wires Correctly

 

You can attach the wires to a plug without paying attention to hot and neutral, and your plug will operate without anything seeming wrong. However, if your plug is on the other end of a wire from a socket or other electrical item, in order for the hot and neutral wiring to operate in a way that protects you, you must wire the plug correctly with regard to hot and neutral. For example, if your plug is on the other end of the wire from a socket, the chance of getting a shock when handling the socket – especially while changing the bulb - is higher if you do not connect the hot and neutral wires correctly on both ends.

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 where the bulb is screwed in.

When wired properly, the metal threads 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.

However, some plugs are non-polarized. A polarized plug will have one prong wider than the other, which is the neutral, and usually silver-colored prong. The hot prong will be narrower and usually gold colored. With a non-polarized plug, you can wire either wire to either prong.

 

Wiring the Plug

 

  1. 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.

  2. 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 plug 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),
    • a fine pair of fabric scissors (for snipping off the end of the cloth braid),
    • silicone tape (to bind ends of cloth covered wire to prevent fraying, available here),
    • 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.



        

    Tools Needed for Wiring a Plug and Wire Stripper Head with Gauge Slots



  3. Cut the wire to the length you want plus 6 inches.

  4. When using any of our plugs aside from our button plugs, separate the interior of the plug from the exterior. Slide the exterior over the end of the wire you are working on with the exterior oriented with the side that takes the interior facing the end of the wire where the plug will be wired. With any of our button plugs, set aside the black cardboard plug cover, partially unscrew both the hot and neutral screws, and slide the plug over the wire with the prongs facing the end of the wire where the plug will be wired.



          
    Plugs with Removable Interior, Wires Unstripped


    Button Plug, Wires Unstripped



  5. Cut the cloth braid off the wire by unraveling the cotton or rayon and snipping it off 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. The amount of cloth to snip and the amount of wire to strip is dependent on the type of plug you use.
    • For our round plug with neck, ribbed round plug with neck, and all of our 3-pronged plugs, strip down 2" of wire to have enough room to tie an underwriter's knot, which we recommend. These are the only plugs we carry that can fit the knot.
    • For our rectangular plugs, strip down 1" of cloth and plastic.
    • For our button plugs, strip down 3/4" of cloth and plastic.


    Cloth Removed, Not Yet Taped



  6. Use a 1.5” length of self-fusing silicone tape to bind the cloth braid down to the 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, half covering the cloth and half covering the insulation. This will prevent issues with the wire fitting in the plug and the tape showing out of the plug's wireway hole. 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. Cut off the plastic and all interior padding (some paper and/or additional plastic), leaving only the exposed interior wires. Tape over the jagged edge of the cut plastic jacket to keep this section neat.



          
    Cloth Removed, Tape Applied on Parallel Cord and Twisted Pair



  7. Strip ½” of the plastic off the ends of the wire. A wire stripper is the best tool for this because it doesn’t cut the copper, just the insulating plastic around the copper. Make sure you use the slot in the stripper that matches the gauge of the wire you are using.

    For our parallel cords you will need to separate the fused hot and neutral wires down to where the wire is taped. Do this by using a utility knife to cut the inset section in the middle of the cord, between the two wires, for just a half inch or so, being extremely careful not to cut the copper in either wire. Once you have done that, you can pull the two wires apart. It is best to cut the wire with the knife for as small a portion as possible so that you do not cut into either wire and expose or cut the strands of copper under the insulation.

          


    Cloth Removed, Tape Applied, Ends Stripped


  8. Twist the exposed end of the neutral wire so that the strands of copper are firmly twisted together. See the chart below for which wire is hot and which is neutral.


    Identifying the Hot, Neutral, and Ground Wires
      Hot Neutral Ground
    Parallel Cord smooth wire ribbed wire none
    Twisted Pair *plain (no stripe) wire *striped wire none
    Three-Conductor black wire white wire green wire
    Plug/Socket narrow prong/gold screw wide prong/silver screw n/a


    * 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.

  9. If you are using the round plug with neck, the ribbed round plug with neck, or any of our three-pronged plugs, tie the underwriter's knot now. 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 plug even with some tension applied to the plug. If you are using a 3-conductor wire, tie the knot using only the black and white wires, ignoring the green wire. If you are using any of our rectangular or button plugs, skip this step.

          
    How to Tie the Underwriter's Knot and the Knot Tied


  10. Make a hook out of the end of the neutral wire.



    Hooked Neutral Wire


  11. If the plug is polarized, put the hook of the neutral wire over the silver screw in the plug, with the hook going clockwise around the screw. If the plug is not polarized, hook the wire around either prong. 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.



          
    Neutral Wire Hooked Onto Silver Screw for Polarized Plug, Either Screw for Non-Polarized


  12. Do the same with the hot wire and the other screw.



          
    Both Wires Hooked on Polarized and Non-Polarized Plug


  13. For three-pronged plugs, now attach the green wire to the green screw. You will need to cut the green wire down about an inch or so since the green wire was not used in the underwriter's knot. This allows all of the wiring to fit inside the plug.

  14. Slip the outside of the plug down the wire and over the plug interior.

  15. If the plug has a yellow, screw-on interior, screw it in tight.



          
    Yellow Interiors Screwed In


    If the plug has a cardboard cover, slide that over the prongs. Note that once you put the cardboard cover on, it can be very hard to remove, so be fairly sure you won't have to remove it. (We do sell replacements, however.)

     

    Putting On the Cardboard Cover