Wire Gauge & Voltage-Drop Calculator
Size a wire run, see the round-trip voltage drop, and check it against the FRC-mandated minimum gauge (R609 / R622 Table 8-4). Provable copper physics in, honest numbers out.
Figures: 2026 REBUILT Game Manual (Version TU22) & AWG/IACS copper constants. Verify against the current official Game Manual before your event.
The wire run
Continuous current the circuit carries.
Distance from the PD board to the device. The tool doubles it internally (supply + return — the ×2 factor).
12 AWG ≈ 0.0808 in dia / 3.31 mm² · 1.588 Ω/1000 ft (solid Cu, 20°C). Smaller number = thicker.
Sets the FRC minimum-gauge check. R622 Table 8-4 — 12 AWG (13 SWG / 4 mm²).
Used only for the gauge recommendation. 3% / 5% are common engineering guidance — not an FRC rule (FRC sets no max drop).
Voltage drop (range)
Low = solid copper @ 20°C (exact table). High = stranded + warm.
Voltage at the load
10.67–10.73 V
12 V nominal − drop
Round-trip resistance
31.8–33.3 mΩ
×2 × 10.00 ft × 1.588 Ω/1000ft
Current
40 A
Load current entered
Electrical length
20.00 ft
10.00 ft one-way × 2
FRC-legal — 12 AWG meets the minimum for this circuit
Minimum for this circuit: 12 AWG. R622 Table 8-4 — 12 AWG (13 SWG / 4 mm²).
Gauge recommendation
No offered gauge (down to 6 AWG) keeps the worst-case drop under 5.0% at 40A over this run — shorten the run, split the load, or raise the target.
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