Crimping and Connectors Done Right

Why connections matter most#

The weakest link in robot electrical reliability is almost always a connection, not a wire. A cold crimp or loose terminal adds resistance, heats up, drops voltage, and eventually fails - often during a match. Learning to make clean, repeatable connections is the single highest-value skill in this branch.

Anderson Powerpole and SB connectors#

Powerpole connectors are genderless plug connectors used for motor and device power; SB50 connectors are the larger battery connectors.

Crimping tips:

• Use a crimper that keeps the contact's round shape - cheap crimpers deform the barrel into an oval and weaken the grip.
• Position the contact with the barrel flush to the jaw and the Anderson logo facing up so the cores aren't twisted when you insert them into the housing.
• For SB50, use a 6 AWG crimp die even on smaller wire - it just makes thicker walls on smaller conductors.
• After crimping, tug the wire firmly to confirm it won't pull out.

WAGO lever connectors#

The PDH uses toolless WAGO-style lever terminals: lift the lever, insert the stripped wire, close the lever. For inline splices, WAGO 221 lever connectors are popular - strip about 11 mm, insert, and clamp. They are reusable and far more reliable than twisting wires together.

Ferrules#

A ferrule is a small metal sleeve crimped onto a stranded wire end. It bundles the strands so they can't splay or work loose in a screw or lever terminal. Strip an appropriate length, slide on the ferrule, and crimp with a ferrule crimper (a four-indent / square crimper gives the best grip). Use ferrules anywhere stranded wire enters a clamping terminal.

Ring and fork terminals#

For screw-stud connections (like motor controller input lugs or the main breaker studs), crimp a ring or fork terminal sized to the wire and stud. Use a ratcheting crimper so every crimp gets full pressure, then heat-shrink the barrel for strain relief and insulation.

Habits of reliable teams#

• Tug-test every connection after making it.
• Heat-shrink exposed barrels to insulate and add strain relief (and to satisfy the R607 insulation rule on battery/breaker terminals).
• Strain-relieve wires so vibration loads a zip-tie, not the connector.
• Keep a crimper, spare contacts, and heat-shrink in the pit kit.

Sources#

• WCP Wiring & Connectors
• WPILib Introduction to FRC Robot Wiring