Wire Sizing

Wire Size for 60 Amp Sub-Panel 100 Feet

Pre-calculated NEC-compliant wire size for 60 amps at 100 feet on a 240V single-phase circuit. Immediate answer below.

Recommended Wire Size

Copper

6 AWG

Voltage drop: 2.46% (5.89V)

Voltage at load: 234.1V

Controlling factor: Ampacity (NEC 310.16)

Aluminum

4 AWG

Voltage drop: 2.54% (6.1V)

Voltage at load: 233.9V

Controlling factor: Ampacity (NEC 310.16)

Based on NEC Table 310.16 (75°C column), single-phase, 240V, 3% max voltage drop, one-way distance 100 ft.

Wire Comparison Table

Wire Size	Ampacity	V-Drop (V)	V-Drop (%)	V at Load
14 AWG	15A	37.68V	15.7%	202.3V
12 AWG	20A	23.76V	9.9%	216.2V
10 AWG	30A	14.88V	6.2%	225.1V
8 AWG	50A	9.34V	3.89%	230.7V
6 AWGREC	65A	5.89V	2.46%	234.1V
4 AWG	85A	3.7V	1.54%	236.3V
3 AWG	100A	2.94V	1.23%	237.1V
2 AWG	115A	2.33V	0.97%	237.7V
1 AWG	130A	1.85V	0.77%	238.2V
1/0 AWG	150A	1.46V	0.61%	238.5V
2/0 AWG	175A	1.16V	0.48%	238.8V
3/0 AWG	200A	0.92V	0.38%	239.1V
4/0 AWG	230A	0.73V	0.3%	239.3V
250 kcmil	255A	0.62V	0.26%	239.4V
300 kcmil	285A	0.51V	0.21%	239.5V
350 kcmil	310A	0.44V	0.18%	239.6V
400 kcmil	335A	0.39V	0.16%	239.6V
500 kcmil	380A	0.31V	0.13%	239.7V

Table shows all standard AWG/kcmil sizes for 60A at 100 ft on 240V (copper). Green check = meets both ampacity and 3% voltage drop. REC = smallest compliant size.

Key Considerations

Sub-panel feeders are subject to NEC 215.2(A)(1) which requires conductors to have ampacity not less than the rating of the overcurrent device. For a 60A sub-panel at 100 feet, voltage drop on the feeder is the primary sizing concern.

Remember that the total voltage drop from the service entrance to the farthest outlet should not exceed 5%. If the feeder uses 2-3%, branch circuits in the sub-panel should keep their drop to 2% or less.

Frequently Asked Questions

What size wire do I need for a sub-panel feeder at 100 feet?▾

For a 60A/240V circuit at 100 feet, use 6 AWG copper (2.46% drop) or 4 AWG aluminum. This keeps voltage drop within the NEC-recommended 3% limit.

Can I use aluminum wire for a 60 amp circuit?▾

Yes. Aluminum wire is a cost-effective alternative for larger circuits. For 60A at 100 feet, use 4 AWG aluminum (2.54% voltage drop). Aluminum requires AL-rated connectors and anti-oxidant compound at all terminations.

What happens if the voltage drop exceeds 3%?▾

Voltage drop above 3% reduces equipment efficiency, can cause motors to overheat, and may violate NEC 210.19(A) Informational Note No. 4. For a 60A circuit at 100 feet on 240V, exceeding 3% means the load receives less than 232.8V, which can damage sensitive electronics and shorten appliance lifespan.

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Need a Custom Calculation?

Different voltage, three-phase, or custom max drop percentage? Use our interactive calculator.

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