What is the amp rating for 16 gauge wire?

Use 13 A for 16 AWG copper on equipment with 75 °C terminations, which covers most breakers and panel lugs. Read 11 A instead when the conductor is inside NM-B cable, and treat 15 A as the derating base only. Aluminium of the same size is about 10 A at 75 °C.

What breaker size goes with 16 AWG copper?

16 AWG is below the smallest standard branch-circuit device rating and is normally used for control, signal or fixture wiring rather than a protected branch circuit.

What is the diameter of 16 AWG wire?

The bare conductor is 0.0508 inches (1.290 mm) in diameter, which is 2,583 circular mils. With THHN/THWN-2 insulation the nominal outside diameter is about 0.096 inches.

What is the resistance of 16 AWG wire?

About 4.0151 ohms per 1000 feet for copper and 6.5815 ohms per 1000 feet for aluminium, at 75 °C.

How far can I run 16 AWG wire?

Distance depends on load and voltage. At 20 A on a 120 V single-phase circuit, 16 AWG copper stays under 3% voltage drop for about 18 feet one-way. Doubling the voltage roughly doubles the allowable distance.

16 AWG Wire — Amp Rating, Ampacity & Diameter

Ampacity, geometry, resistance, conduit fill and maximum run length for 16 AWG conductors in copper and aluminium.

Quick answer

16 AWG copper carries about 13 A at 75 °C (11 A at 60 °C, 15 A at 90 °C). The bare conductor is 0.0508 in (1.29 mm) and 2,583 circular mils, with 4.0151 Ω per 1000 ft.

Copper 75 °C

13A

Aluminium 75 °C

10A

Diameter

0.0508in

Circular mils

2,583

Full specification

Size designation	16 AWG
AWG gauge number	16
Circular mils	2,583
kcmil	2.58
Bare diameter (in)	0.0508
Bare diameter (mm)	1.290
Cross-section (mm²)	1.31
THHN/THWN-2 OD (in)	0.096
Insulated area (sq in)	0.0072
Copper resistance (Ω/1000 ft)	4.0151
Aluminium resistance (Ω/1000 ft)	6.5815
Max standard breaker (Cu, 75 °C)	Below branch-circuit ratings

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	15 A	14 A	12 A	11 A
6	12 A	11 A	10 A	8 A
9	11 A	10 A	9 A	7 A
15	8 A	7 A	6 A	5 A
25	7 A	6 A	6 A	5 A

Source & method: The governing value is also capped by the termination rating, commonly 75 °C, which for this size is 13 A. Run your own conditions.

Maximum run length at 3% voltage drop

One-way distance for 16 AWG copper before drop exceeds 3%.

Load	120 V 1Ø	240 V 1Ø	208 V 3Ø	480 V 3Ø
10 A	36 ft	72 ft	72 ft	166 ft
15 A	24 ft	48 ft	48 ft	110 ft
20 A	18 ft	36 ft	36 ft	83 ft
30 A	12 ft	24 ft	24 ft	55 ft
40 A	9 ft	18 ft	18 ft	41 ft
50 A	7 ft	14 ft	14 ft	33 ft

Calculate your exact run

How many 16 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	16	29	47	82	112	185	323	400	400	400
IMC	18	32	52	91	122	200	283	400	400	400
RMC	17	30	49	84	114	188	268	400	400	400
PVC Sch 40	15	28	45	80	109	181	259	400	400	400
PVC Sch 80	12	22	38	68	94	158	227	356	400	400

Mix conductor sizes in the fill calculator

16 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	11 A	13 A	15 A
Aluminium	9 A	10 A	12 A

The 16 AWG copper ampacity figure you use on a real circuit is the 75 °C column, 13 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, 15 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 77% of the copper value (10 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 16 AWG with the sizes immediately above and below it before sizing a circuit.

Smaller18 AWG10 A copper at 75 °C · 0.0403" diameter Larger14 AWG18 A copper at 75 °C · 0.0641" diameter

Size	Cu 75 °C	Al 75 °C	Diameter (in)	Circular mils
18 AWG	10 A	8 A	0.0403	1,624
16 AWG (this page)	13 A	10 A	0.0508	2,583
14 AWG	18 A	14 A	0.0641	4,107
12 AWG	24 A	19 A	0.0808	6,530

16 AWG amp rating, diameter and metric equivalent

The amp rating for 16 AWG wire depends on the insulation temperature rating, not on the conductor alone. Copper ampacity is about 11 A on a 60 °C conductor, 13 A at 75 °C and 15 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, 16 AWG is 0.0508 in (1.29 mm) in bare diameter, which is 2,583 circular mils. The cross sectional area works out to 1.31 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 16 AWG actually gets used

16 AWG lives in cords and control wiring: extension cords and tool cords, appliance leads, motor control and interlock wiring, and fixture whips. It is used as flexible stranded cord conductor far more often than as a conductor pulled in raceway.

Cord ampacity is a different question from raceway ampacity, because a coiled or bundled cord cannot shed heat the way a single conductor in open air can. That is why a 16 AWG extension cord that is fine at 10 A for a short run overheats coiled on a reel, and why cord length and gauge are printed together on the tag.

Frequently asked

How many amps can 16 AWG wire carry?: 16 AWG copper is estimated at 11 A at 60 °C, 13 A at 75 °C and 15 A at 90 °C, at 30 °C ambient with no more than three current-carrying conductors. Aluminium of the same size is about 10 A at 75 °C.
What is the amp rating for 16 gauge wire?: Use 13 A for 16 AWG copper on equipment with 75 °C terminations, which covers most breakers and panel lugs. Read 11 A instead when the conductor is inside NM-B cable, and treat 15 A as the derating base only. Aluminium of the same size is about 10 A at 75 °C.
What breaker size goes with 16 AWG copper?: 16 AWG is below the smallest standard branch-circuit device rating and is normally used for control, signal or fixture wiring rather than a protected branch circuit.
What is the diameter of 16 AWG wire?: The bare conductor is 0.0508 inches (1.290 mm) in diameter, which is 2,583 circular mils. With THHN/THWN-2 insulation the nominal outside diameter is about 0.096 inches.
What is the resistance of 16 AWG wire?: About 4.0151 ohms per 1000 feet for copper and 6.5815 ohms per 1000 feet for aluminium, at 75 °C.
How far can I run 16 AWG wire?: Distance depends on load and voltage. At 20 A on a 120 V single-phase circuit, 16 AWG copper stays under 3% voltage drop for about 18 feet one-way. Doubling the voltage roughly doubles the allowable distance.