Wire strippers are hand tools designed to remove insulation from electrical wire without damaging the metal conductor underneath. They matter because a clean strip makes a strong electrical connection, while a nicked or weakened conductor can break, overheat, or create an unsafe circuit. In a workshop, the right wire stripper helps make wiring faster, more repeatable, and safer.
Understanding how the tool grips, cuts, and pulls insulation helps students connect mechanical force with practical electrical work.
A manual wire stripper uses matched notches sized for specific wire gauges, so the cutting edges slice through insulation but stop before cutting deeply into the copper. When the handles close, the jaws apply force over a small area, increasing pressure at the insulation. Pulling the tool away then creates shear and friction that slide the cut insulation off the conductor.
Proper stripping depends on wire gauge, insulation thickness, tool alignment, and controlled hand force.
Key Facts
- Wire gauge numbers get smaller as wire diameter gets larger, so 12 AWG is thicker than 18 AWG.
- Pressure = Force / Area, so the small cutting edge creates high pressure on the insulation.
- Use the notch that matches the wire gauge to avoid cutting copper strands or leaving insulation behind.
- Copper is the conductor, and plastic or rubber insulation is the electrical barrier around it.
- Electrical resistance follows R = ρL / A, so reducing conductor area by nicking strands increases resistance.
- Strip length should match the connector depth, often about 6 mm to 12 mm for many small terminals.
Vocabulary
- Wire stripper
- A tool with sized cutting notches used to remove insulation from electrical wire without cutting the conductor.
- Conductor
- A material, such as copper, that allows electric charge to move through it easily.
- Insulation
- A nonconducting covering around a wire that prevents unwanted contact and protects against electric shock.
- Wire gauge
- A standard number that describes wire diameter, with lower AWG numbers representing thicker wire.
- Stranded wire
- A wire made of many thin metal strands bundled together for flexibility.
Common Mistakes to Avoid
- Using the wrong gauge notch cuts too deeply or not deeply enough. This can nick copper strands, weaken the wire, or leave insulation that blocks a good connection.
- Pulling the stripper at an angle twists and scrapes the conductor. Keep the tool aligned with the wire so the insulation slides off cleanly.
- Stripping too much insulation exposes extra metal. Exposed conductor can touch nearby parts and cause a short circuit or shock hazard.
- Forgetting to check that the circuit is de-energized is unsafe. Always disconnect power before stripping or handling wires in a circuit.
Practice Questions
- 1 A terminal requires 8 mm of bare copper. If a student strips 13 mm, how many millimeters of extra conductor are exposed?
- 2 A wire has resistance R = ρL / A. If a nick removes 10 percent of the conductor area, the new area is 0.90A. What is the new resistance in terms of the original resistance R?
- 3 Explain why a wire stripper notch that is slightly too small can be more dangerous to a connection than a notch that is slightly too large.