How to Crimp Wire Terminals
The success of your electrical repair or additions is dependent on three factors: adequate power, correct wire size to carry that power and proper connection of the wire to the terminal. Without a good connection between the wire and terminal attachment, all your work will be wasted. A bad crimp on a wire terminal can lead to spotty power, causing the appliance or fixture to work erratically or even be a fire hazard. There is a basic technique to crimp wire terminals correctly. It is easy to learn and will help prevent your hard work from creating more problems than you had before. Does this Spark an idea?
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Things You'll Need
- Terminal crimping tool
- Electrical terminal (sized to match your wire)
- Electrical tape
- Box knife
Instructions
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Make sure the end of the wire that you will be placing into the terminal attachment is cut evenly. If you need to recut the end, use the wire cutter built into your terminal crimping tool. Depending on the kind of terminal crimping tool you have, the wire cutter may be located either directly in the head of the pliers or behind the main hinge but before the handles. You will recognize the wire cutting part of the pliers because with the pliers closed this section will look like two straight edges that are flush together with no space between. Many pliers will slightly indent the blades of the cutter so they are even more noticeable in the body of the pliers.
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Hold your terminal against the end of the wire. Match the end of the wire with the end of the plastic and metal tube just before the flare of the terminal.
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3
Strip the insulation from the wire from the beginning of the terminal to the end. Do this by placing the wire in the matching hole in the pliers. Each side of the pliers has semicircles cut into it so that when the pliers are closed they form complete circles. These holes are labeled with wire size so you can easily match, for example, your 14-gauge wire to the hole marked 14. If you do not know the size of the wire, try each hole until you find one with a snug fit. Insert your wire, and hold the pliers firmly closed. Spin the pliers completely around the wire (360 degrees); doing this will cut the insulating sheathing. Now pull the pliers off the wire while still holding them closed. This will strip the casing from the wire. Depending on how thick the insulation is on your wire, you may have to repeat this step several times before the insulation comes off.
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4
Insert the bare wire into the terminal end (not the side with the flared terminal), and press the terminal onto the wire so the end of the terminal tube butts against the beginning of the wire's insulation.
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5
Locate the crimping section of your pliers, and identify which part of it is meant for the size of wire that you are working on. The crimping section is typically located in the head of the pliers at the nose (the very end of the pliers). It will look almost like a series of waves, with a rounded high point with a number written by it that then will dip and rise to a new high point with another number. These numbers will tell you which rise is meant for your size of wire (which you learned from which stripping hole you had to use).
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Open the pliers, and place the center of the rise for your wire just behind the end of the terminal casing (just before where the flare begins) with the wire and the terminal casing between the two parts of the rise. Gently close the pliers to make sure that the rise falls in the middle of the casing. Once you are sure it is going to fall in the middle, squeeze the pliers shut as hard as you can and then open the pliers. You should see an indent in your terminal casing that looks white. The white is from the change to the plastic under the impact of the crimp. Repeat this action in the middle of the terminal casing as well so you have two crimp marks on the casing.
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Test your crimp. Pull lightly on the wire to see if it will come out of the terminal. If it does, remove the terminal, select a new one and start again. If the wire does not come out and does not feel loose, you have successfully added a crimped wire terminal.
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Tips & Warnings
Wrap the entire length of the terminal casing with electrical tape plus 1 inch of the wire past the casing. This is an added safety measure that helps to prevent sparking and helps to keep the connection firmly together under stress.
Make sure that the wire and terminal size you are using is appropriate to the electrical load and distance that it must travel (see Resources). Using an inappropriate size of wire or terminal can lead to overheating and the creation of a fire hazard.
