Wire Gauge Selection by Current (AWG)

Why gauge matters

Wire has resistance. Push too much current through too thin a wire and it heats up, drops voltage, and can melt its insulation or start a fire. American Wire Gauge (AWG) is the standard sizing - counterintuitively, smaller AWG numbers mean thicker wire (6 AWG is much thicker than 18 AWG).

The FRC wire gauge table (Rule R622, Table 8-4)

The Game Manual ties minimum wire gauge directly to the branch circuit's breaker/fuse rating:

These are minimums - you may always go thicker. Many teams use 12 AWG for all 40A motor branches for simplicity.

Concrete examples

• A Kraken X60 or Falcon 500 drive motor on a 40A breaker: 12 AWG to the motor controller.
• The roboRIO on a 10A channel: 18 AWG.
• The VH-109 radio 12V input: 18 AWG (R626 also requires 18 AWG or larger here).
• The CAN bus between devices: 28 AWG minimum (CAN is a signal-level circuit per Table 8-4); many teams use twisted-pair cable and heavier 22 AWG for durability, though neither is required by rule.
• The battery and main breaker leads: 6 AWG (some high-power drivetrains use heavier 4 AWG).

Note: wires originally attached to a legal device (e.g. the leads molded onto a SPARK MAX) are part of the device and exempt, provided they are fed by the smallest breaker/fuse that lets the device work.

Stranded, not solid

FRC robots vibrate and flex constantly, so always use high-strand-count stranded copper wire, never solid wire. Stranded wire survives vibration and routes more easily. High-strand 12 AWG is flexible enough to route around tight bends and connectors despite its thicker gauge.

Color coding (R624)

Non-signal wiring with constant polarity must follow polarity colors: red, yellow, white, brown, or black-with-stripe for positive; black or blue for negative. Consistent color coding makes debugging dramatically faster and is required for inspection.

Sources

• WPILib Introduction to FRC Robot Wiring
• 2025 Game Manual Section 8