Between its neighbours
4 AWG has 59 % more copper than 6 AWG and 21 % less than 3 AWG. Its DC resistance is 0.308 Ω per 1000 ft at 75 °C (aluminum 0.508), and 1000 ft of it carries 126.3 lb of copper.
4 AWG wire: amps, diameter & uses
4 AWG copper is 0.2043" solid (0.232" as 7-strand) and 21.2 mm². Table 310.16 rates it 70 / 85 / 95 A at 60 / 75 / 90 °C, so it protects up to a 80 A breaker on 75 °C terminals; aluminum of this size carries 65 A. Typical use: 70–85 A feeders and 60 A EV chargers in the wall (4/3 NM-B).
01 · 1:1 wire gauge · caliper
4 AWG · concentric stranded copper
THIS IS:
4 AWG COPPER · 80 A BREAKER · 5.19 MM COPPER
Gauge
4 AWG
concentric stranded copper
Breaker
80 A
copper, max
Measured
5.89 mm
0.2320"
The gap is 5.89 mm (0.2320"), which reads as 4 AWG concentric stranded copper. Measure bare copper for the gauge: insulation is far thicker than the metal.
- Meets NEC 2023 Table 310.16 at 75°C — verify with your local AHJ/inspector310.16
- Drawn at true sizecalibrated screen
4 AWG
- Solid diameter
- 0.204"5.19 mm · ASTM B258 formula
- Stranded (7 strands)
- 0.232"5.89 mm · Table 8
- THHN outside
- 0.324"8.23 mm · 0.0824 in² · Table 5
- Area
- 41,740 cmil21.15 mm² · nearest IEC 25 mm²
- DC resistance, 75 °C
- 0.308 Ω/1000 ftaluminum 0.508 Ω/1000 ft · Table 8
- Copper weight
- 126.3 lb/1000 ft
Ampacity
- Copper 60 / 75 / 90 °C
- 70 / 85 / 95 ANM-B uses the 60 °C column (334.80)
- Aluminum 60 / 75 / 90 °C
- 55 / 65 / 75 A
- Largest breaker (Cu, 75 °C)
- 80 Aampacity ≥ breaker
Other gauges
- Nearest SWG
- SWG 40.232" · 5.893 mm
- IEC 60228
- 25 mm²between 16 and 25 mm²
4 AWG at a glance
Size
- Solid diameter
- 0.2043" · 5.19 mm
- Stranded (7)
- 0.232"
- THHN outside
- 0.324"
- Area
- 41,740 cmil · 21.15 mm²
- Metric
- 16 – 25 mm²
- SWG nearest
- 5 (5.385 mm)
Amps
- Copper 60/75/90 °C
- 70 / 85 / 95 A
- Aluminum 75 °C
- 65 A
- Max breaker, THHN
- 80 A
- As NM-B cable
- not made
- Ground for it
- 8 AWG
Run & fit
- 120 V at 64 A
- 91 ft at 3 %
- 240 V at 64 A
- 182 ft at 3 %
- THHN in ½" EMT
- 1
- THHN in ¾" EMT
- 2
- Copper weight
- 126.3 lb/1000 ft
4 AWG reference 24 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | ||||
|---|---|---|---|---|
| 584 | 5844 | 11688 | ||
| 292 | 2922 | 5844 | ||
| 116 | 1168 | 2337 | ||
| 58 | 584 | 1168 | ||
| 38 | 389 | 779 | ||
| 29 | 292 | 584 | ||
| 19 | 194 | 389 | ||
| 14 | 146 | 292 | ||
| 9 | 97 | 194 | ||
| 7 | 73 | 146 |
| Actions | |||||||
|---|---|---|---|---|---|---|---|
| 1 | 2 | 4 | 7 | 10 | 16 | ||
| 1 | 2 | 4 | 7 | 9 | 16 | ||
| 1 | 1 | 3 | 6 | 8 | 14 | ||
| 1 | 3 | 4 | 8 | 11 | 17 | ||
| 1 | 2 | 4 | 7 | 10 | 16 | ||
| 1 | 2 | 4 | 6 | 9 | 16 | ||
| 1 | 2 | 4 | 7 | 9 | 15 |
05 / Field guide
4 AWG
feeder copper.
4 AWG copper is 0.2043" solid (0.232" as 7-strand) and 21.2 mm². Table 310.16 rates it 70 / 85 / 95 A at 60 / 75 / 90 °C, so it protects up to an 80 A breaker on 75 °C terminals; aluminum of this size carries 65 A. Typical use: 70–85 A feeders and 60 A EV chargers in the wall (4/3 NM-B).
Feeders and services
4 AWG is the usual choice for 70–85 A feeders and 60 A EV chargers in the wall (4/3 NM-B). It is not made as NM-B cable; use THHN or XHHW in conduit, or SER/USE cable. The equipment ground for its largest breaker is 8 AWG.
On the 1:1 gauge
The caliper above opens at 5.19 mm. Lay a stripped length along the lines and step the gauge with ← and → until the wire just fills the gap.
Questions
Answered plainly.
01How many amps can 4 AWG wire carry?
+−
4 AWG copper is rated 70 A at 60 °C, 85 A at 75 °C and 95 A at 90 °C (NEC Table 310.16, 30 °C, three conductors or fewer). Aluminum of the same size: 65 A at 75 °C.
02What size breaker for 4 AWG wire?
+−
Up to 80 A with THHN on 75 °C terminals; the next size up is allowed by 240.4(B) only where the ampacity is not itself a standard rating.
03What is the diameter of 4 AWG wire?
+−
0.2043 inch (5.19 mm) solid, 0.232 inch stranded (7 strands), about 0.324 inch with THHN insulation.
04What is 4 AWG in mm²?
+−
21.15 mm² (41,740 circular mils). The IEC sizes either side are 16 and 25 mm²; replace it with 25 mm², not the smaller one.
05How far can 4 AWG wire run?
+−
At 64 A and 3 % drop, 91 ft one way at 120 V and 182 ft at 240 V (Table 8 resistance, 0.308 Ω per 1000 ft at 75 °C). Lighter loads go proportionally further.
06How many 4 AWG wires fit in ½" EMT?
+−
1 THHN conductors in ½" EMT, 2 in ¾" and 4 in 1" (NEC Chapter 9, 40 % fill for three or more).
07Can 4 AWG be used for a house service?
+−
Yes: by the 83 % rule (310.12) 4 AWG copper serves a dwelling’s 100 A service, or the feeder carrying its whole load. A subpanel feeder does not get the 83 % rule.