Wire & Watts

What size wire for 60 amps at 50 feet?

Updated by Biel Vazquez

Short answer: For a 60 amp load 50 feet away (one way) at 240 V, use 6 AWG copper or 4 AWG aluminum in conduit with 75 °C terminations, which keeps voltage drop at 1.2% and 1.3%. In NM-B (Romex) cable it is 4 AWG copper. The breaker stays 60 A; distance does not force a larger size.

60 amps at 50 feet: wire size by type

240 V single phase, 60 A load on a 60 A breaker, 50 ft one way, 30 °C ambient. Computed with our wire size calculator.
Wire typeSize by ampacitySize for 50 ft (≤3% drop)Voltage drop
Copper THHN/THWN-2 in conduit, 75 °C6 AWG6 AWG1.23%
Aluminum XHHW-2 in conduit, 75 °C4 AWG4 AWG1.27%
Copper NM-B (Romex) cable, 60 °C4 AWG4 AWG0.77%
Aluminum SER / NM-B cable, 60 °C3 AWG3 AWG1.01%

At 50 ft, voltage drop stays under 3% with the ampacity size, so distance does not force a bigger wire. NEC 250.122(B) then requires the equipment ground to be increased in proportion: start from 10 AWG copper for a 60 A breaker.

Voltage drop of each gauge over 50 ft

Copper, 240 V, resistance from NEC Chapter 9 Table 8 at 75 °C. The current travels out and back, so the wire length is twice the run.
WireVolts lost at 60 ADrop at 60 ADrop at 48 A (80%)
6 AWG copper2.95 V1.23%0.98%
4 AWG copper1.85 V0.77%0.62%
3 AWG copper1.47 V0.61%0.49%
2 AWG copper1.16 V0.49%0.39%
1 AWG copper0.92 V0.39%0.31%
voltage drop = 2 × length × resistance per 1,000 ft × amps ÷ 1,000
            = 2 × 50 × R(6 AWG) × 60 ÷ 1,000 = 2.95 V
percent     = 2.95 ÷ 240 × 100 = 1.23%

If the real load is the 80% continuous maximum (48 A, as with an EV charger on a 60 A breaker), copper in conduit can be 8 AWG. 3% is the NEC's recommendation for a branch circuit (Informational Note to 210.19), not a hard rule, but motors, compressors and chargers run better with it.

Same 60 A, other distances

75 ft · 100 ft · 150 ft · 200 ft. Minimum sizes with no distance correction: what size wire for a 60 amp breaker.

Other loads at 50 feet

30 A · 40 A · 50 A · 100 A · 125 A · 150 A · 200 A

Change the numbers in the calculator

Safety. A 60 A circuit or feeder over 50 ft needs a permit almost everywhere in the US. Buried runs have their own depth and conduit rules (NEC 300.5), and equipment nameplates override any general table.

Keep reading

Sources: NFPA 70 (NEC), NEC Chapter 9, Table 8: conductor properties. Method and tables: methodology.