Full Robot Wiring Walkthrough

A sensible build order

Wiring a robot is much easier when you do it in the right sequence. Here is the order experienced teams follow, mirroring the official WPILib wiring guide.

1. Mount the major components

Lay out and bolt down the PD , roboRIO , radio , and motor controllers on the electrical board before wiring anything. Leave room for wire runs and keep the main breaker reachable from outside (R612).

2. Main power path (6 AWG)

• Crimp 6 AWG leads with an Anderson SB50 to the battery side.
• Battery (+) -> 120A main breaker -> PD (+).
• Battery (-) -> PD (-).
• Use ring terminal lugs on the breaker studs and tighten firmly; insulate all exposed terminals (R607).

3. roboRIO power (18 AWG, 10A)

• Run 18 AWG from a non-switchable channel (PDH 20/21/22) or the PDP’s dedicated terminal, protected with a 10A fuse/breaker.
• Red to V , black to C on the roboRIO power connector.

4. Radio power (18 AWG, 10A) - 2026 method

• Power the VH-109 directly from the PD : 12V into the radio’s Weidmuller input (18 AWG, R626) and/or passive PoE into the RIO Ethernet port, from a 10A-protected channel. Do not use a VRM or RPM for the radio.
• Connect the radio’s RIO Ethernet port to the roboRIO’s Ethernet port.

5. Motor controllers (12 AWG)

• Run 12 AWG from 40A high-current channels to each motor controller’s power input.
• On the PDH, use the WAGO lever terminals ; on the controller end, crimp ferrules or ring terminals.
• Insert a 40A breaker in each motor channel.

6. CAN bus (22 AWG twisted pair)

• Daisy-chain roboRIO - > controllers -> PD, CANH-to-CANH (yellow) and CANL-to-CANL (green), with the two ends terminated.

7. Robot Signal Light (R709)

• Wire the RSL to the roboRIO’s ‘RSL’ terminals; jumper an 855PB for solid-light operation so it flashes when the robot is enabled.

Before first power-on

• Double-check polarity everywhere - reversed power can destroy electronics.
• Tug-test every connection.
• Confirm the CAN bus reads ~60 ohms.
• Insert the main breaker last, then power on and watch for green LEDs.

Sources

• WPILib Introduction to FRC Robot Wiring
• WPILib Hardware Component Overview

Key takeaways

• Mount components first, then wire in order: main power, roboRIO, radio, motors, CAN, RSL.
• Use 6 AWG for main power, 18 AWG (10A) for roboRIO/radio, 12 AWG for 40A motor branches.
• For 2026, power the radio directly from the PD (12V and/or passive PoE) - no VRM/RPM.
• Daisy-chain CAN, verify ~60 ohms, double-check polarity, and tug-test every connection before inserting the main breaker.

This lesson was adapted from learnfrc.com.