Between its neighbours
1/0 AWG has 26 % more copper than 1 AWG and 21 % less than 2/0 AWG. Its DC resistance is 0.122 Ω per 1000 ft at 75 °C (aluminum 0.201), and 1000 ft of it carries 319.6 lb of copper.
1/0 AWG wire: amps, diameter & uses
1/0 AWG copper is 0.3249" solid (0.372" as 19-strand) and 53.5 mm². Table 310.16 rates it 125 / 150 / 170 A at 60 / 75 / 90 °C, so it protects up to a 150 A breaker on 75 °C terminals; aluminum of this size carries 120 A. Typical use: 150 A feeders and 125 A copper services.
01 · 1:1 wire gauge · caliper
1/0 AWG · concentric stranded copper
THIS IS:
1/0 AWG COPPER · 150 A BREAKER · 8.25 MM COPPER
Gauge
1/0 AWG
concentric stranded copper
Breaker
150 A
copper, max
Measured
9.45 mm
0.3720"
The gap is 9.45 mm (0.3720"), which reads as 1/0 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
1/0 AWG
- Solid diameter
- 0.325"8.25 mm · ASTM B258 formula
- Stranded (19 strands)
- 0.372"9.45 mm · Table 8
- THHN outside
- 0.486"12.34 mm · 0.1855 in² · Table 5
- Area
- 105,600 cmil53.51 mm² · nearest IEC 50 mm²
- DC resistance, 75 °C
- 0.122 Ω/1000 ftaluminum 0.201 Ω/1000 ft · Table 8
- Copper weight
- 319.6 lb/1000 ft
Ampacity
- Copper 60 / 75 / 90 °C
- 125 / 150 / 170 ANM-B uses the 60 °C column (334.80)
- Aluminum 60 / 75 / 90 °C
- 100 / 120 / 135 A
- Largest breaker (Cu, 75 °C)
- 150 Aampacity ≥ breaker
Other gauges
- Nearest SWG
- SWG 3/00.372" · 9.449 mm
- IEC 60228
- 50 mm²between 50 and 70 mm²
1/0 AWG at a glance
Size
- Solid diameter
- 0.3249" · 8.25 mm
- Stranded (19)
- 0.372"
- THHN outside
- 0.486"
- Area
- 105,600 cmil · 53.51 mm²
- Metric
- 50 – 70 mm²
- SWG nearest
- 0 (8.23 mm)
Amps
- Copper 60/75/90 °C
- 125 / 150 / 170 A
- Aluminum 75 °C
- 120 A
- Max breaker, THHN
- 150 A
- As NM-B cable
- not made
- Ground for it
- 6 AWG
Run & fit
- 120 V at 120 A
- 122 ft at 3 %
- 240 V at 120 A
- 245 ft at 3 %
- THHN in ½" EMT
- 1
- THHN in ¾" EMT
- 1
- Copper weight
- 319.6 lb/1000 ft
1/0 AWG reference 26 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | ||||
|---|---|---|---|---|
| 1475 | 14754 | 29508 | ||
| 737 | 7377 | 14754 | ||
| 295 | 2950 | 5901 | ||
| 147 | 1475 | 2950 | ||
| 98 | 983 | 1967 | ||
| 73 | 737 | 1475 | ||
| 49 | 491 | 983 | ||
| 36 | 368 | 737 | ||
| 24 | 245 | 491 | ||
| 18 | 184 | 368 | ||
| 14 | 147 | 295 | ||
| 9 | 98 | 196 |
| Actions | |||||||
|---|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 3 | 4 | 7 | ||
| 1 | 1 | 1 | 3 | 4 | 7 | ||
| 0 | 1 | 1 | 2 | 3 | 6 | ||
| 1 | 1 | 1 | 3 | 4 | 8 | ||
| 1 | 1 | 1 | 3 | 4 | 7 | ||
| 1 | 1 | 1 | 2 | 4 | 7 | ||
| 1 | 1 | 1 | 3 | 4 | 7 |
05 / Field guide
1/0 AWG
feeder copper.
1/0 AWG copper is 0.3249" solid (0.372" as 19-strand) and 53.5 mm². Table 310.16 rates it 125 / 150 / 170 A at 60 / 75 / 90 °C, so it protects up to a 150 A breaker on 75 °C terminals; aluminum of this size carries 120 A. Typical use: 150 A feeders and 125 A copper services.
Feeders and services
1/0 AWG is the usual choice for 150 A feeders and 125 A copper services. 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 6 AWG.
On the 1:1 gauge
The caliper above opens at 8.25 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 1/0 AWG wire carry?
+−
1/0 AWG copper is rated 125 A at 60 °C, 150 A at 75 °C and 170 A at 90 °C (NEC Table 310.16, 30 °C, three conductors or fewer). Aluminum of the same size: 120 A at 75 °C.
02What size breaker for 1/0 AWG wire?
+−
Up to 150 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 1/0 AWG wire?
+−
0.3249 inch (8.25 mm) solid, 0.372 inch stranded (19 strands), about 0.486 inch with THHN insulation.
04What is 1/0 AWG in mm²?
+−
53.51 mm² (105,600 circular mils). The IEC sizes either side are 50 and 70 mm²; replace it with 70 mm², not the smaller one.
05How far can 1/0 AWG wire run?
+−
At 120 A and 3 % drop, 122 ft one way at 120 V and 245 ft at 240 V (Table 8 resistance, 0.122 Ω per 1000 ft at 75 °C). Lighter loads go proportionally further.
06How many 1/0 AWG wires fit in ½" EMT?
+−
1 THHN conductors in ½" EMT, 1 in ¾" and 1 in 1" (NEC Chapter 9, 40 % fill for three or more).
07Can 1/0 AWG be used for a house service?
+−
Yes: by the 83 % rule (310.12) 1/0 AWG copper serves a dwelling’s 175 A service, or the feeder carrying its whole load. A subpanel feeder does not get the 83 % rule.