What wire gauge do FRC rules require?

FRC's rules set a minimum wire gauge for each branch-circuit breaker size. As a common guideline, a 40 A circuit needs at least 12 AWG, a 30 A circuit at least 14 AWG, and a 20 A circuit at least 18 AWG, while the main battery and PDH/PDP leads use 6 AWG. Exact minimum-AWG values can change year to year, so always check the current game manual's wiring rules, which this tool does for you.

How much voltage drop is acceptable on an FRC robot?

There is no single legal limit, but keeping voltage drop under roughly 3-5% of battery voltage on a run is a good target. Excessive drop on long, thin runs wastes power as heat and can contribute to brownouts under high current. Enter your current, run length, and gauge to see the drop and decide whether to size up.

Why does wire length matter for voltage drop?

Voltage drop equals current × resistance, and a wire's resistance is proportional to its length. Doubling a run doubles its resistance and its voltage drop, so long runs to distant mechanisms often need a thicker gauge than a short run carrying the same current.

tools / frc-wire-gauge-calculator

Is this wire thick enough, and is it legal?

Round-trip voltage drop from Ohm’s law, checked against the minimum gauge the manual sets for your breaker size. Copper physics in, honest numbers out.

Figures track the 2026 REBUILT Game Manual (TU22) and the AWG/IACS copper constants. Verify against the current manual before an event.

the run is doubled, supply and return

verdict / passes the gauge rule

12 AWG is legal on this circuit.

Minimum here is 12 AWG. R622 Table 8-4: 12 AWG (13 SWG / 4 mm²).

1.27-1.33volts dropped over the run

10.6-11.1%of 12 V nominal, over 5%

10.67-10.73volts left at the load

the run / six numbers

Describe the wire you are about to cut.

Load current (A)

Continuous current the circuit carries.

One-way run length

PD board to the device. The tool doubles it for supply and return.

Wire gauge (AWG)

Smaller number means thicker wire.

Circuit type / protection

Sets the minimum-gauge check. R622 Table 8-4: 12 AWG (13 SWG / 4 mm²).

Voltage-drop target (%)

Drives the ladder below. Common guidance, not an FRC rule.

Stranded and warm, the realistic rangeReal FRC wire is stranded and runs warm. Adds 2 to 5% plus temperature and shows a range. Turn it off for the exact solid-copper 20°C figure.

conductor: 12 AWG, 0.0808 in dia, 3.31mm²
resistance: 1.588Ω/1000 ft solid Cu at 20°C
circuit: 31.8 to 33.3mΩ round trip
electrical length: 20.00 ft, being 10.00 ft each way

every gauge / against this run

What each gauge would have done.

40 A over 10.00 ft one way, worst case, stranded and warm. A row is only usable if it is both legal on this circuit and under your 5.0% target.

nothing down to 6 AWG holds this target, shorten the run or split the load

Voltage drop and legality for every offered wire gauge on the run described above.
gauge	Ω/1000 ft	volts dropped	% of 12 V	rule	verdict
6 AWG	0.3951	0.33 V	2.8%	meets the minimum	works
8 AWG	0.6282	0.53 V	4.4%	meets the minimum	works
10 AWG	0.9989	0.84 V	7.0%	meets the minimum	legal, over target
12 AWG	1.588	1.33 V	11.1%	meets the minimum	legal, over target · selected
14 AWG	2.525	2.12 V	17.7%	below 12 AWG	not legal here
16 AWG	4.016	3.37 V	28.1%	below 12 AWG	not legal here
18 AWG	6.385	5.36 V	44.7%	below 12 AWG	not legal here
20 AWG	10.150	8.53 V	71.1%	below 12 AWG	not legal here
22 AWG	16.140	13.56 V	113.0%	below 12 AWG	not legal here
24 AWG	25.670	21.56 V	179.7%	below 12 AWG	not legal here

what “legal” does not meanTable 8-4 and R609 set the minimum safe size, not the size that keeps voltage where you want it. A gauge can pass inspection and still drop most of a volt on a long drive run, so read the drop column, not just the rule column.

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Describe the wire you are about to cut.

Load current (A)

Continuous current the circuit carries.

One-way run length

PD board to the device. The tool doubles it for supply and return.

Wire gauge (AWG)

Smaller number means thicker wire.

Circuit type / protection

Sets the minimum-gauge check. R622 Table 8-4: 12 AWG (13 SWG / 4 mm²).

Voltage-drop target (%)

Drives the ladder below. Common guidance, not an FRC rule.

Stranded and warm, the realistic rangeReal FRC wire is stranded and runs warm. Adds 2 to 5% plus temperature and shows a range. Turn it off for the exact solid-copper 20°C figure.

conductor: 12 AWG, 0.0808 in dia, 3.31mm²
resistance: 1.588Ω/1000 ft solid Cu at 20°C
circuit: 31.8 to 33.3mΩ round trip
electrical length: 20.00 ft, being 10.00 ft each way

gauge

Ω/1000 ft

volts dropped

% of 12 V

rule

verdict

6 AWG

0.3951

0.33 V

2.8%

meets the minimum

works

8 AWG

0.6282

0.53 V

4.4%

meets the minimum

works

10 AWG

0.9989

0.84 V

7.0%

meets the minimum

legal, over target

12 AWG

1.588

1.33 V

11.1%

meets the minimum

legal, over target · selected

14 AWG

2.525

2.12 V

17.7%

below 12 AWG

not legal here

16 AWG

4.016

3.37 V

28.1%

below 12 AWG

not legal here

18 AWG

6.385

5.36 V

44.7%

below 12 AWG

not legal here

20 AWG

10.150

8.53 V

71.1%

below 12 AWG

not legal here

22 AWG

16.140

13.56 V

113.0%

below 12 AWG

not legal here

24 AWG

25.670

21.56 V

179.7%

below 12 AWG

not legal here