What Wire Size for 1.42 Amps at 175 Feet?

14 AWG copper is a typical pick for 1.42A at 175 feet on 120V under a 3% drop target. It balances NEC branch-circuit ampacity and voltage drop over distance. Drop with 14 AWG at these inputs: 1.56V (1.3%). Real-world sizing also depends on insulation temperature rating, cable type, and install conditions.

1.42A at 175ft · 120V single-phase / DC · 3% drop target

14 AWG copper

On a 240V circuit (copper)14 AWG

Voltage drop (120V, copper)1.56V (1.3%)

No aluminum row: every aluminum size in our reference table sits past the 3% drop target at 175 feet on 120V, or the amperage is below the 30A residential threshold where aluminum is not a typical pick. On a higher source voltage, a shorter run, or a looser drop target, aluminum is still the standard feeder material at higher amperages.

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

Amps

Feet

Gauge (Cu / Al)

14 AWG Cu

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

14 AWG branch-circuit OCP (15A under NEC 240.4(D)) ≥ 1.42A ✓

The conductor needs to carry at least 1.42A 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), 14 AWG sits at a branch-circuit OCP of 15A because the NEC 240.4(D) small-conductor rule caps it below the 20A 75°C ampacity table value. That is not a universal number: NM-B cable (Romex) follows the 60°C column in residential use per NEC 334.80 (14 AWG NM-B = 15A), 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 × 1.42 × 3.14) ÷ (1000 × 120) × 100 = 1.3%

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?

The recommended gauge is already the smallest suitable option in our table.

What If You Go One Size Larger?

Using 12 AWG (one size thicker) would reduce voltage drop to 0.9841V (0.8201% on 120V). More expensive wire but better performance and more headroom for future load increases.

Wattage at This Amperage

1.42A at 120V delivers 170.4 watts (DC / resistive load). See conversion.

Related Calculations

trending_down V-drop: 14 AWG, 1.42A, 175ft electric_bolt 1.42A to watts at 120V functions Wire sizing formula

Frequently Asked Questions

What wire size for 1.42 amps at 175 feet on 120V?expand_more

1.42A at 175ft on 120V is commonly served by 14 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.

Copper or aluminum wire for 1.42A?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 1.42A residential branch-circuit territory, copper is the default. Aluminum in 14/12/10 AWG is not typical for residential branches, both for code reasons (the NEC 240.4(D) small-conductor rule caps aluminum branch OCP tighter than copper) and because termination and anti-oxidation requirements add cost at that scale.

Can I run 1.42A 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.

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.

Why does distance affect wire size?expand_more

Voltage drop scales linearly with distance: doubling the one-way run length doubles the drop in volts. At 1.42A on 120V, a 175ft run is often served by 14 AWG to land under the 3% drop target, a run half that length can sometimes use one gauge thinner, and a run double that length usually needs one or two gauges thicker. Ampacity is set by the conductor itself (Table 310.16 at the applicable termination temperature), so the binding constraint is ampacity on short runs and voltage drop on long runs.

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.