Every professional electrician makes daily use of a common tool known as wire strippers, and most own several different forms of this tool. Every DIYer who does any kind of electrical repair should also own some version of this tool. Especially useful is a version commonly known as a combination tool, which not only has a wire stripping function, but also a plier tip, cable-cutting blades, and crimping tools for electronics work.
The Function of Combination Wire Strippers
There are tools known as wire strippers that serve only this function—to strip the plastic insulation off individual conductors so they can be attached to screw terminals or joined together with wire connectors. Most types of wire strippers, however, also serve other functions. These multi-function versions are often called combination tools or multifunction wire strippers. They have sharp cutting jaws to cut NM cable or trim individual wires down to size. They may have gripping plier tips that can be used to bend wires. Some versions have slots that can be used for making crimp connections. Wire strippers or combination tools should not be confused with a cable ripper, however, which is a different tool used only to cut away the outer vinyl sheathing from NM cable.
In whatever form the tool takes, a wire stripper has a series of labeled holes that match the common wire gauges. When you insert the wire into the proper hole and close the tool's handle, it precisely severs through the plastic insulation layer without damaging the copper wire. The tool then removes the wire insulation, using one of two methods.
Types of Wire Strippers
One type of "normal" wire strippers (combination tools fall into this category) are small, flat tools that look like pliers. They are inexpensive tools, usually costing $10 to $15 and are very simple to use. With the handles closed, you will see a series of labeled holes that match the common wire gauges.
Another type of wire stripper is a self-stripping tool that removes wire insulation with a compound action. This means that three actions take place when you squeeze the handle: grip, strip, and remove. After you precisely place the wire in the head and squeeze the handle, the stripper grabs onto the wire, cuts the insulation, and completely removes it from the wire, all in one motion. Self-stripping wire strippers are about three times more expensive than normal strippers. They serve one function only, and are normally owned by professional electricians who prefer specialty tools for each function. DIYers normally are better served with a combination tool that serves multiple functions.
How to Use Combination Wire Strippers
Although different manufacturers offer different versions of the tool, the process for stripping wires is largely the same with each tool. This is the process for the "normal," combination-style tool:
- Find the wire gauge. Identify the gauge of the copper wire to be stripped. You can find this on the outermost sheathing that binds multiple wires together inside an NM cable. With a number such as 12/2, for example, the first number is wire gauge. The most common wire gauges in household wiring will be either 14- or 12-gauge. Less common is 10-gauge, which is normally used for high high-draw appliances like clothes dryers and air conditioners.
- Match the wire to the tool: Match the wire gauge with the appropriately labeled hole on the wire stripper. This step is essential: if you choose a hole that is too big, the insulation will not be fully cut and you'll have a hard time stripping it; if you choose a hole that is too small, the wire may be nicked or even severed entirely.
- Open the tool and seat the wire. Open the wire stripper handles. "Seat" the wire into one side of the proper hole. Slowly press the handles together until they can go no farther. This action will cut through the insulation on the wire.
- Twist (optional): If the wire insulation does not fully cut, you may have to gently rotate the wire within the hole (or the wire stripper around the wire, whichever is easier). You do not have to rotate far: just a quarter turn in one direction and back.
- Strip the insulation: Pull the wire stripper towards the cut end of the wire to remove the insulation. The action is like pulling a sock off a foot. Some users find it easiest to push against the tool using the thumb on the hand that is gripping the wire, while the other hand holds the handles of the tool firmly shut.