How to Properly Crimp Wire Connectors | The Exact Steps

Getting a crimp wrong means a loose connection that can overheat, fail, or cause a short. The process isn’t complicated, but it demands specific steps and the right gear. Here’s exactly how to do it right the first time — from stripping to final inspection.

What You Need for a Proper Crimp

The three critical pieces are the connector, the wire, and the crimp tool. They have to match. Use a connector rated for the exact wire gauge — never force a 14 AWG wire into an 18 AWG terminal.

If the installed terminal looks like it’s meant for our recommended wire crimp connectors, double-check it’s listed for your wire type before you start.

The Steps to Crimp a Connector Correctly

Strip the insulation to the exact length specified by the connector or tool chart — just enough so the bare conductor fills the barrel depth, no more. If you nick or ring the strands while stripping, cut the wire back and start over; a nicked strand is a stress riser that breaks under vibration.

Insert the stripped wire fully into the terminal barrel. All strands must be inside the crimp zone. On connectors with an inspection window, you should be able to see the conductor through it. No loose strands should hang outside — they can short against adjacent contacts.

Place the loaded terminal into the correct die cavity of your ratcheting crimper. The tool markings or color bands tell you the right position. Squeeze the handles through the full ratchet cycle.

After the crimp, inspect the joint. Look for a proper bellmouth at the wire entry, full conductor fill across the barrel width, and no sharp edges, flash, or burrs. Then perform a firm tug on the wire — if it pulls free from the terminal, discard the connector and remake the connection. The TE Connectivity guide on crimping details these verification steps for industrial and automotive work.

Common Crimping Mistakes to Avoid

• Wrong connector size or wire gauge — match them exactly per the manufacturer’s spec.
• Nicked or ringed strands — always start fresh if the wire is damaged.
• Wire not inserted fully — the conductor must reach the end of the barrel.
• Crimping in the wrong die cavity or outside the marked zone — follow the tool’s color bands or markings.
• Releasing a ratcheting tool early — let it complete the full cycle every time.
• Using solid wire — stranded wire only for crimp terminals.
• Mismatched metals — never use a copper connector on aluminum wire.

If you catch any of these during your pull test, cut off the terminal and start over. A bad crimp costs nothing to remake; a failed connection down the line costs time and equipment.