What Wire Size for 230.83 Amps at 50 Feet?

For a 230.83-amp circuit running 50 feet on 120V, 250 kcmil copper is the smallest gauge in our table that both stays within the 3% drop target and covers the branch-circuit OCP cap for 230.83A. A shorter run of 25 feet at the same voltage often allows 250 kcmil. Treat this as an estimate, not an install spec.

230.83A at 50ft · 120V single-phase / DC · 3% drop target

250 kcmil copper

Aluminum option350 kcmil

On a 240V circuit (copper)250 kcmil

Voltage drop (120V, copper)1.19V (0.9906%)

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

Amps

Feet

Gauge (Cu / Al)

250 kcmil Cu / 350 kcmil 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

250 kcmil branch-circuit OCP (255A) ≥ 230.83A ✓

The conductor needs to carry at least 230.83A 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), 250 kcmil sits at a branch-circuit OCP of 255A. That is not a universal number: NM-B cable (Romex) follows the 60°C column in residential use per NEC 334.80 (250 kcmil NM-B = 215A), 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 × 50 × 230.83 × 0.0515) ÷ (1000 × 120) × 100 = 0.9906%

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 4/0 AWG (one size thinner) at these inputs gives a voltage drop of 1.4V (1.17% on 120V), and its branch-circuit OCP cap under typical conditions is 230A.

Limiting factor here: branch-circuit ampacity. 4/0 AWG has a branch-circuit OCP cap of 230A under the typical 75°C-termination assumptions used here, which is below the 230.83A load. For this load it shouldn't be used without reassessing against the actual termination temperature, cable type, ambient conditions, and any 240.4(D) or 240.4(B) provisions.

What If You Go One Size Larger?

Using 300 kcmil (one size thicker) would reduce voltage drop to 0.9903V (0.8252% on 120V). More expensive wire but better performance and more headroom for future load increases.

Wattage at This Amperage

230.83A at 120V delivers 27,699.6 watts (DC / resistive load). See conversion.

Related Calculations

Frequently Asked Questions

What wire size for 230.83 amps at 50 feet on 120V?expand_more

230.83A at 50ft on 120V is commonly served by 250 kcmil 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 250 kcmil 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.

Do I need to upsize wire for continuous loads?expand_more

NEC 210.19(A) (branch circuits) and 215.3 (feeders) size the conductor and overcurrent device at not less than 125% of the continuous load plus 100% of any non-continuous load. For a 230.83A continuous load that points the sizing math at the 288.54A figure, but the actual conductor and breaker pick still depends on termination temperature rating, cable type, bundling and ambient conditions, and any 240.4(D) or 240.4(B) provisions. Treat this as the input to a sizing decision, not the output.

Can I run 230.83A on a longer distance?expand_more

Yes, but you may need thicker wire. At 100ft 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.

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.