Between its neighbours
3/0 AWG has 26 % more copper than 2/0 AWG and 21 % less than 4/0 AWG. Its DC resistance is 0.0766 Ω per 1000 ft at 75 °C (aluminum 0.126), and 1000 ft of it carries 507.9 lb of copper.
3/0 AWG wire: amps, diameter & uses
3/0 AWG copper is 0.4096" solid (0.47" as 19-strand) and 85.0 mm². Table 310.16 rates it 165 / 200 / 225 A at 60 / 75 / 90 °C, so it protects up to a 200 A breaker on 75 °C terminals; aluminum of this size carries 155 A. Typical use: 200 A copper feeders and 175 A services.
01 · 1:1 wire gauge · caliper
3/0 AWG · concentric stranded copper
THIS IS:
3/0 AWG COPPER · 200 A BREAKER · 10.40 MM COPPER
Gauge
3/0 AWG
concentric stranded copper
Breaker
200 A
copper, max
Measured
11.94 mm
0.4700"
The gap is 11.94 mm (0.4700"), which reads as 3/0 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
3/0 AWG
- Solid diameter
- 0.410"10.40 mm · ASTM B258 formula
- Stranded (19 strands)
- 0.470"11.94 mm · Table 8
- THHN outside
- 0.584"14.83 mm · 0.2679 in² · Table 5
- Area
- 167,800 cmil85.03 mm² · nearest IEC 95 mm²
- DC resistance, 75 °C
- 0.0766 Ω/1000 ftaluminum 0.126 Ω/1000 ft · Table 8
- Copper weight
- 507.9 lb/1000 ft
Ampacity
- Copper 60 / 75 / 90 °C
- 165 / 200 / 225 ANM-B uses the 60 °C column (334.80)
- Aluminum 60 / 75 / 90 °C
- 130 / 155 / 175 A
- Largest breaker (Cu, 75 °C)
- 200 Aampacity ≥ breaker
Other gauges
- Nearest SWG
- SWG 6/00.464" · 11.786 mm
- IEC 60228
- 95 mm²between 70 and 95 mm²
3/0 AWG at a glance
Size
- Solid diameter
- 0.4096" · 10.40 mm
- Stranded (19)
- 0.47"
- THHN outside
- 0.584"
- Area
- 167,800 cmil · 85.03 mm²
- Metric
- 70 – 95 mm²
- SWG nearest
- 4/0 (10.16 mm)
Amps
- Copper 60/75/90 °C
- 165 / 200 / 225 A
- Aluminum 75 °C
- 155 A
- Max breaker, THHN
- 200 A
- As NM-B cable
- not made
- Ground for it
- 6 AWG
Run & fit
- 120 V at 160 A
- 146 ft at 3 %
- 240 V at 160 A
- 293 ft at 3 %
- THHN in ½" EMT
- 0
- THHN in ¾" EMT
- 1
- Copper weight
- 507.9 lb/1000 ft
3/0 AWG reference 27 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | ||||
|---|---|---|---|---|
| 2349 | 23498 | 46997 | ||
| 1174 | 11749 | 23498 | ||
| 469 | 4699 | 9399 | ||
| 234 | 2349 | 4699 | ||
| 156 | 1566 | 3133 | ||
| 117 | 1174 | 2349 | ||
| 78 | 783 | 1566 | ||
| 58 | 587 | 1174 | ||
| 39 | 391 | 783 | ||
| 29 | 293 | 587 | ||
| 23 | 234 | 469 | ||
| 15 | 156 | 313 | ||
| 11 | 117 | 234 |
| Actions | |||||||
|---|---|---|---|---|---|---|---|
| 0 | 1 | 1 | 1 | 3 | 5 | ||
| 0 | 1 | 1 | 1 | 3 | 5 | ||
| 0 | 1 | 1 | 1 | 2 | 4 | ||
| 0 | 1 | 1 | 2 | 3 | 5 | ||
| 0 | 1 | 1 | 1 | 3 | 5 | ||
| 0 | 1 | 1 | 1 | 2 | 5 | ||
| 0 | 1 | 1 | 1 | 3 | 5 |
05 / Field guide
3/0 AWG
feeder copper.
3/0 AWG copper is 0.4096" solid (0.47" as 19-strand) and 85.0 mm². Table 310.16 rates it 165 / 200 / 225 A at 60 / 75 / 90 °C, so it protects up to a 200 A breaker on 75 °C terminals; aluminum of this size carries 155 A. Typical use: 200 A copper feeders and 175 A services.
Feeders and services
3/0 AWG is the usual choice for 200 A copper feeders and 175 A 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 10.40 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 3/0 AWG wire carry?
+−
3/0 AWG copper is rated 165 A at 60 °C, 200 A at 75 °C and 225 A at 90 °C (NEC Table 310.16, 30 °C, three conductors or fewer). Aluminum of the same size: 155 A at 75 °C.
02What size breaker for 3/0 AWG wire?
+−
Up to 200 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 3/0 AWG wire?
+−
0.4096 inch (10.40 mm) solid, 0.47 inch stranded (19 strands), about 0.584 inch with THHN insulation.
04What is 3/0 AWG in mm²?
+−
85.03 mm² (167,800 circular mils). The IEC sizes either side are 70 and 95 mm²; replace it with 95 mm², not the smaller one.
05How far can 3/0 AWG wire run?
+−
At 160 A and 3 % drop, 146 ft one way at 120 V and 293 ft at 240 V (Table 8 resistance, 0.0766 Ω per 1000 ft at 75 °C). Lighter loads go proportionally further.
06How many 3/0 AWG wires fit in ½" EMT?
+−
0 THHN conductors in ½" EMT, 1 in ¾" and 1 in 1" (NEC Chapter 9, 40 % fill for three or more).