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How many amps can 16 AWG wire carry?

10 A — maximum overcurrent device, NEC 240.4(D).

16 AWG copper is listed at 18 A in the 90 °C column of NEC Table 310.16, but you cannot protect it at that current: NEC 240.4(D) caps the overcurrent device at 10 A, and a continuous load at 8 A. It is a fixture wire, not a branch-circuit conductor.

Safety first. These figures are an educational reference before derating, not a code substitute. Verify against the current NEC and have circuits reviewed by a licensed electrician.

16 AWG ampacity — copper vs aluminum

16 AWG ampacity by conductor material and insulation temperature rating.
Material 60 °C 75 °C 90 °C Breaker cap
Copper — — 18 A 10 A
Aluminum not rated not rated not rated —

Values are amps at a 30 °C ambient, before derating for temperature or conductor bundling. Most installations must use the 75 °C column regardless of the wire's own rating, because terminals and breakers are rated 75 °C (NEC 110.14(C)).

Why the three numbers disagree. Table 310.16 lists 16 AWG copper only in the 90 °C column (18 A), because it is a fixture wire rather than a general branch-circuit conductor. NEC 240.4(D) then limits its overcurrent device to 10 A, and a load running three hours or more to 8 A. The 18 A figure describes the wire; the 10 A figure describes the circuit you are allowed to build with it.

How far can you run 16 AWG at 10 A?

Ampacity answers whether a conductor will overheat. It says nothing about whether the voltage still arrives at the far end. Past roughly fifty feet, voltage drop is usually what really sets the wire size. These are the longest one-way runs that keep drop within the 3% recommended by the NEC 210.19(A) informational note, for 16 AWG copper carrying 10 A.

Maximum one-way run length for 16 AWG copper at 10 A by system voltage.
System Typical use Max run at 3% Drop at 100 ft
120 V standard receptacle and lighting circuits 45 ft 8.03 V
240 V ranges, dryers, EV chargers, feeders 90 ft 8.03 V
12 V DC automotive, marine, solar and battery runs 4 ft 8.03 V

Single-phase, one-way distance, copper at 20 °C. Aluminum reaches its limit at roughly 60% of these distances for the same size. The 3% figure is a recommendation in an informational note, not a code requirement.

16 AWG wire size — diameter, area and resistance

Diameter

0.0508 in · 1.291 mm

Cross-section

1.309 mm² · 2,583 cmil

Nearest metric size

1.5 mm² (rounds up)

Copper resistance

4.0155 Ω per 1000 ft @ 20 °C

Aluminum resistance

6.7059 Ω per 1000 ft

Area

2.583 kcmil

Diameter is computed from the ASTM B258 definition d = 0.005 × 92^((36 − n)/39), not read from a rounded table. Resistance uses the annealed-copper constant 10.371 Ω·cmil/ft at 20 °C.

What 16 AWG wire is used for

The 16 gauge mistake worth knowing

Three different numbers all claim to be “16 AWG ampacity” and they disagree: Table 310.16 shows 18 A at 90 °C, NEC 240.4(D) caps the overcurrent device at 10 A, and a continuous load is limited to 8 A. The 18 A figure is the one most charts print and the one you can least often use.