What Wire Size for 56.6 Amps at 175 Feet?

For 56.6 amps at 175 feet on a 120V circuit, 1 AWG copper is a common starting point under a 3% voltage-drop target. On a 240V circuit the same current often allows 4 AWG, because the 3% allowable drop is a larger number of volts at higher source voltage. Actual install sizing still depends on conductor material, insulation/termination temperature, cable type, ambient and bundling conditions, and local code.

56.6A at 175ft · 120V single-phase / DC · 3% drop target

1 AWG copper

Aluminum option1/0 AWG

On a 240V circuit (copper)4 AWG

Voltage drop (120V, copper)3.05V (2.54%)

check_circle Within the 3% branch and 5% feeder+branch total drop targets

Amps

Feet

Gauge (Cu / Al)

1 AWG Cu / 1/0 AWG Al

Assumes a 120V source on a single-phase / DC circuit and a 3% voltage-drop target. Each material is picked independently against the same target, so the copper and aluminum results are two separate recommendations, not an ampacity equivalence. Switch to three-phase L-L →

How Wire Size Is Determined

Step 1: NEC Branch-Circuit Ampacity

1 AWG branch-circuit OCP (130A) ≥ 56.6A ✓

The conductor needs to carry at least 56.6A without going past its temperature rating, and the OCP protecting it needs to respect the NEC branch-circuit cap. Under the typical assumptions used in this table (copper, 75°C termination, no bundling or ambient derates), 1 AWG sits at a branch-circuit OCP of 130A. That is not a universal number: NM-B cable (Romex) follows the 60°C column in residential use per NEC 334.80 (1 AWG NM-B = 110A), bundling more than three current-carrying conductors requires a 310.15(C)(1) adjustment, ambient temperatures above 30°C require a 310.15(B) correction, and 60°C terminations on typical residential equipment can pull the usable value lower still. Use the nameplate and local code for the actual install value.

Step 2: Voltage Drop Check

%VD = (2 × L × I × R) ÷ (1000 × V) × 100 (single-phase / DC; round-trip factor of 2)

(2 × 175 × 56.6 × 0.154) ÷ (1000 × 120) × 100 = 2.54%

NEC 210.19(A) Informational Note 4 recommends ≤ 3% for branch circuits and ≤ 5% for feeder + branch total as performance targets, not hard code requirements. This run sits within the 3% target used for this calculation.

Practical Information

What If You Go One Size Smaller?

Using 2 AWG (one size thinner) at these inputs gives a voltage drop of 3.84V (3.2% on 120V), and its branch-circuit OCP cap under typical conditions is 115A.

Limiting factor here: voltage drop, not ampacity. 2 AWG is still above the 56.6A load at its 115A branch-circuit OCP cap, so the conductor temperature margin is fine for this run. What pushes it off this page's pick is the 3.2% drop sitting past the 3% target, which is a performance recommendation (NEC 210.19(A) Informational Note 4), not a code requirement. On shorter runs or at higher source voltage the same gauge would often clear the drop target too.

What If You Go One Size Larger?

Using 1/0 AWG (one size thicker) would reduce voltage drop to 2.42V (2.01% on 120V). More expensive wire but better performance and more headroom for future load increases.

Wattage at This Amperage

56.6A at 120V delivers 6,792 watts (DC / resistive load). See conversion.

Related Calculations

trending_down V-drop: 1 AWG, 56.6A, 175ft electric_bolt 56.6A to watts at 120V functions Wire sizing formula

Frequently Asked Questions

What wire size for 56.6 amps at 175 feet on 120V?expand_more

56.6A at 175ft on 120V is commonly served by 1 AWG copper to land under the 3% voltage-drop target, under the typical 75°C-termination assumptions used in this table. Actual install sizing also depends on conductor material, insulation and termination temperature rating, cable type, ambient and bundling conditions, and local code.

How much does 1 AWG wire cost?expand_more

Copper wire pricing tracks the LME copper spot price and varies with insulation type, cable assembly (THHN, NM-B, MC, SE, USE), and quantity. Check current pricing with a local electrical supply house or distributor catalog; commodity-driven numbers inlined on a calculator page age quickly.

What is the NEC voltage drop recommendation?expand_more

NEC 210.19(A) Informational Note 4 recommends ≤3% for branch circuits and ≤5% total (feeder + branch). These are performance recommendations, not hard code requirements.

Can I run 56.6A on a longer distance?expand_more

Yes, but you may need thicker wire. At 350ft on 120V, check the wire size calculator. You may need to go up one or two gauges.

Copper or aluminum wire for 56.6A?expand_more

Copper and aluminum are picked independently against the same drop target on this site; neither pick implies ampacity equivalence with the other. At 56.6A, both materials are valid. Copper is common for branch circuits at this range; AA-8000 series aluminum shows up for longer runs and sub-panel feeders where the cost savings outweigh the gauge upsize. Aluminum has lower conductivity than copper, so when each material is run through the drop-target pick independently, the aluminum result typically lands one to two gauges larger than the copper result for the same duty. That gap is the result of running both picks against the same drop-target constraint, not an ampacity-equivalence rule.

This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.