What is the amp rating for 6 gauge wire?

Use 59 A for 6 AWG copper on equipment with 75 °C terminations, which covers most breakers and panel lugs. Read 50 A instead when the conductor is inside NM-B cable, and treat 67 A as the derating base only. Aluminium of the same size is about 46 A at 75 °C.

What breaker size goes with 6 AWG copper?

The largest standard overcurrent device that 6 AWG copper supports at 75 °C is 50 A. For a continuous load, the load itself must not exceed 80% of that rating.

What is the diameter of 6 AWG wire?

The bare conductor is 0.1620 inches (4.115 mm) in diameter, which is 26,251 circular mils. With THHN/THWN-2 insulation the nominal outside diameter is about 0.254 inches.

What is the resistance of 6 AWG wire?

About 0.3951 ohms per 1000 feet for copper and 0.6476 ohms per 1000 feet for aluminium, at 75 °C.

How far can I run 6 AWG wire?

Distance depends on load and voltage. At 20 A on a 120 V single-phase circuit, 6 AWG copper stays under 3% voltage drop for about 183 feet one-way. Doubling the voltage roughly doubles the allowable distance.

6 AWG Wire — Amp Rating, Ampacity & Diameter

Ampacity, geometry, resistance, conduit fill and maximum run length for 6 AWG conductors in copper and aluminium.

Quick answer

6 AWG copper carries about 59 A at 75 °C (50 A at 60 °C, 67 A at 90 °C). The bare conductor is 0.1620 in (4.11 mm) and 26,251 circular mils, with 0.3951 Ω per 1000 ft. It pairs with a 50 A breaker at 75 °C terminations.

Copper 75 °C

59A

Aluminium 75 °C

46A

Diameter

0.1620in

Circular mils

26,251

Full specification

Size designation	6 AWG
AWG gauge number	6
Circular mils	26,251
kcmil	26.25
Bare diameter (in)	0.1620
Bare diameter (mm)	4.115
Cross-section (mm²)	13.30
THHN/THWN-2 OD (in)	0.254
Insulated area (sq in)	0.0507
Copper resistance (Ω/1000 ft)	0.3951
Aluminium resistance (Ω/1000 ft)	0.6476
Max standard breaker (Cu, 75 °C)	50 A

Published standardFormula estimate

Ampacity with derating

Estimated ampacity from the 90 °C column at various ambient temperatures and conductor counts.

Conductors in raceway	30 °C ambient	40 °C ambient	50 °C ambient	60 °C ambient
3	67 A	61 A	55 A	47 A
6	54 A	49 A	44 A	38 A
9	47 A	43 A	38 A	33 A
15	34 A	31 A	27 A	24 A
25	30 A	28 A	25 A	21 A

Source & method: The governing value is also capped by the termination rating, commonly 75 °C, which for this size is 59 A. Run your own conditions.

Maximum run length at 3% voltage drop

One-way distance for 6 AWG copper before drop exceeds 3%.

Load	120 V 1Ø	240 V 1Ø	208 V 3Ø	480 V 3Ø
10 A	366 ft	732 ft	733 ft	1,691 ft
15 A	244 ft	488 ft	488 ft	1,127 ft
20 A	183 ft	366 ft	366 ft	845 ft
30 A	122 ft	244 ft	244 ft	563 ft
40 A	91 ft	183 ft	183 ft	422 ft
50 A	73 ft	146 ft	146 ft	338 ft

Calculate your exact run

How many 6 AWG conductors fit in conduit

Maximum count of this size alone, at the fill percentage matching the resulting count.

Conduit	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	2-1/2"	3"	3-1/2"	4"
EMT	1	4	6	11	16	26	46	69	91	116
IMC	2	4	7	12	17	28	40	62	83	107
RMC	1	4	7	12	16	26	38	59	79	101
PVC Sch 40	1	4	6	11	15	25	37	57	76	99
PVC Sch 80	1	3	5	9	13	22	32	50	68	88

Mix conductor sizes in the fill calculator

6 AWG copper ampacity vs aluminium ampacity

Ampacity by conductor material and insulation temperature rating, at 30 °C ambient with no more than three current-carrying conductors.

Material	60 °C (TW, NM-B)	75 °C (THW, THWN, XHHW)	90 °C (THHN, THWN-2, XHHW-2)
Copper	50 A	59 A	67 A
Aluminium	39 A	46 A	52 A

The 6 AWG copper ampacity figure you use on a real circuit is the 75 °C column, 59 A, because breakers and lugs on most equipment are listed for 75 °C even when the conductor insulation is rated 90 °C. The 90 °C value, 67 A, is the starting point for ambient and conductor-count derating only — you derate from 90 °C, then cap the answer at the termination rating.

Aluminium of the same size carries roughly 78% of the copper value (46 A at 75 °C), so an aluminium feeder is normally stepped up one to two sizes to match a copper circuit. NM-B cable is always read from the 60 °C column regardless of the temperature stamped on the conductor insulation.

Source & method: Values are model estimates from conductor geometry and resistivity — see methodology and verify against the NEC edition enforced locally.

Neighbouring sizes

Compare 6 AWG with the sizes immediately above and below it before sizing a circuit.

Smaller8 AWG44 A copper at 75 °C · 0.1285" diameter Larger4 AWG80 A copper at 75 °C · 0.2043" diameter

Size	Cu 75 °C	Al 75 °C	Diameter (in)	Circular mils
10 AWG	32 A	25 A	0.1019	10,383
8 AWG	44 A	34 A	0.1285	16,510
6 AWG (this page)	59 A	46 A	0.1620	26,251
4 AWG	80 A	62 A	0.2043	41,741
3 AWG	93 A	73 A	0.2294	52,635

Circuits that use 6 AWG

Breaker ratings whose smallest copper conductor at 75 °C terminations is 6 AWG.

6 AWG amp rating, diameter and metric equivalent

The amp rating for 6 AWG wire depends on the insulation temperature rating, not on the conductor alone. Copper ampacity is about 50 A on a 60 °C conductor, 59 A at 75 °C and 67 A at 90 °C, all at 30 °C ambient with no more than three current-carrying conductors in the raceway. The carrying capacity drops from there in hot spaces or crowded conduit, and terminations rated 75 °C cap what you can actually use.

Geometrically, 6 AWG is 0.1620 in (4.11 mm) in bare diameter, which is 26,251 circular mils. The cross sectional area works out to 13.30 mm², so the nearest IEC 60228 metric conductor is the next standard size at or above that figure — AWG sizes and mm² sizes never line up exactly, so round up rather than to the closest value.

American Wire Gauge (AWG) is a standard specification for the sizes of solid round wires used as electrical conductors, and the AWG number counts the drawing operations used to reach the diameter. That is why larger gauges are thinner wire and why standardized wire steps follow a fixed ratio: one AWG step changes diameter by about 12.2% and area by about 26%. Above 1 AWG the American standard continues 1/0 to 4/0, then switches to kcmil for anything larger.

Where 6 AWG actually gets used

6 AWG is the standard 55 to 65 A conductor: 60 A subpanel feeders, larger ranges, 48 A Level 2 EV charging on a 60 A circuit, and grounding electrode conductors on services up to 200 A. It is also where copper cost starts to push installations toward aluminium equivalents, since aluminium of the same ampacity is substantially cheaper per foot.

Pulling tension and conduit fill become real design inputs at 6 AWG. Three current-carrying conductors plus an equipment ground in 3/4" EMT is already near the fill limit, and long pulls with multiple bends often force 1" raceway for a circuit that would otherwise fit — a raceway decision driven by geometry, not by the conductor's rating.

Frequently asked

How many amps can 6 AWG wire carry?: 6 AWG copper is estimated at 50 A at 60 °C, 59 A at 75 °C and 67 A at 90 °C, at 30 °C ambient with no more than three current-carrying conductors. Aluminium of the same size is about 46 A at 75 °C.
What is the amp rating for 6 gauge wire?: Use 59 A for 6 AWG copper on equipment with 75 °C terminations, which covers most breakers and panel lugs. Read 50 A instead when the conductor is inside NM-B cable, and treat 67 A as the derating base only. Aluminium of the same size is about 46 A at 75 °C.
What breaker size goes with 6 AWG copper?: The largest standard overcurrent device that 6 AWG copper supports at 75 °C is 50 A. For a continuous load, the load itself must not exceed 80% of that rating.
What is the diameter of 6 AWG wire?: The bare conductor is 0.1620 inches (4.115 mm) in diameter, which is 26,251 circular mils. With THHN/THWN-2 insulation the nominal outside diameter is about 0.254 inches.
What is the resistance of 6 AWG wire?: About 0.3951 ohms per 1000 feet for copper and 0.6476 ohms per 1000 feet for aluminium, at 75 °C.
How far can I run 6 AWG wire?: Distance depends on load and voltage. At 20 A on a 120 V single-phase circuit, 6 AWG copper stays under 3% voltage drop for about 183 feet one-way. Doubling the voltage roughly doubles the allowable distance.