Wire Strippers & Crimpers

Strippers and crimpers are everyday electrical tools. Used carelessly, they leave nicked wires and loose crimps that overheat and cause fires later. Used on live wires, they can kill you now.

• Electricians
• Low-voltage techs
• Maintenance

Start with a dead circuit

Ordinary strippers and crimpers aren’t insulated. Before stripping or cutting wires, turn off the power, lock and tag it out, and test that it’s dead with a tested meter. See Lockout/Tagout and Test Meters. If work near live parts can’t be avoided, only qualified persons may do it, with rated insulated tools. See Insulated Hand Tools.

Stripping right

• Use the hole that matches the wire gauge and type (solid or stranded). Too small nicks or cuts strands.
• Strip only as much as the terminal needs, usually marked on the device or terminal.
• Check the conductor: no nicks, rings or cut strands. A nicked conductor is weaker and can overheat. Cut it off and strip again.
• Pull straight off, not at an angle, to avoid scoring the copper.

Crimping right

• Match the terminal to the wire size and the crimper die to the terminal (colors and sizes are marked).
• Use a ratcheting crimper for important connections; it won’t release until the crimp is complete.
• Put the crimp in the right place on the barrel, with the conductor fully inserted.
• Pull test every crimp by hand. A good crimp doesn’t move.
• Large lugs need the specific die or hydraulic crimper the lug maker lists.

Protect yourself

• Eye protection: clipped wire ends and strands fly when cut. Point the cut end away from people.
• Hand strain: repeated crimping is hard on the hands. Use spring-loaded, well-sized handles, or a power crimper for big jobs. See Ergonomic Hand Tools.
• Sharp ends: stripped strands can puncture fingers; twist or terminate them right away.

Signs of a bad connection

• Strands sticking out of the terminal or wire nut
• Bare copper showing past the terminal
• Terminal that turns or pulls off by hand
• Discolored, melted or brittle insulation near a connection
• Warm devices, flickering lights or a burning smell

Last updated: October 2, 2026