Robot Electrical Safety

Respect for electricity

The Safety Manual states that proper use of and respect for electricity is paramount. Two domains matter for FRC teams: the shop's AC power (wall outlets, extension cords, chargers) and the robot's DC power (battery, breaker, distribution).

Shop AC power

• Inspect cords and extension cords routinely for good condition — no broken insulation or exposed wiring (the Safety Checklist asks this directly).
• Avoid overloading and daisy-chaining: do not plug an extension cord into another extension cord, an extension cord into a power strip, or a multi-outlet receptacle into a power strip or extension cord. At events, use power strips properly — do not daisy-chain them or exceed the strip's rated capacity, and follow the guideline of no more than one power strip per outlet.
• Place battery chargers where air circulates so they don't overheat.

The robot's DC electrical system

While the full wiring rules live in the Game Manual's ROBOT Construction Rules, a beginner should understand the safety-critical pieces (per WPILib's wiring docs and the Game Manual):

• The 120A main circuit breaker is the robot's master power switch. It must be quickly and safely accessible from the exterior of the robot, and it is the only 120A breaker allowed. Opening it (releasing the re-set lever) de-energizes the robot — your first step before servicing, followed by unplugging the battery.
• The battery connects through an Anderson SB connector. The pink/red SB50 with 6 AWG copper leads is the strongly recommended standard, color-coded for polarity, with leads no longer than ~12 inches. Batteries supplied through FIRST come with a pink/red SB50 connector that should not be removed.
• A 6 AWG wire runs from the main breaker to the Power Distribution Hub (PDH) — or the older Power Distribution Panel (PDP) — which fuses and distributes power to motor controllers and electronics.

Avoiding the classic electrical injuries

The single most common dangerous mistake is shorting the battery or a high-current connection. Cover exposed battery terminals and connections with insulating material (electrical tape or tubing), keep loose metal tools away from terminals, and never leave a wrench resting near a battery. A short can produce hundreds of amps, intense heat, burns, and even an explosion.

Work de-energized

The FIRST best practice bears repeating: de-energize the robot before working on it unless absolutely necessary. Open the main breaker, unplug the battery, and make sure teammates know work is in progress. The Safety Checklist's stored-energy section even asks whether, in the pit, the team ensures no one is working on the robot while it is energized — make the honest answer "yes" every time. When a robot is powered on but not enabled, or is enabled to test, keep people behind shielding or in a marked-off area.

Inspect and improve

Use the Safety Checklist's electrical questions every meeting: Are cords and plugs free of broken insulation? Are outlets free of overload? Is the charger ventilated? Are batteries in visibly good condition with unbent terminals and no cracks? Logging and fixing every "no" through the Corrective and Preventative Action Plan is how a team turns inspection into real improvement.