3/0 AWG (American Wire Gauge) wire specifications: 10.4049 mm diameter, 85.0288 mm² area, 200A ampacity (copper, 75°C). Resistance, weight, and common uses.
| Diameter | 10.4049 mm · 0.409642" · 409.64 mils |
| Cross-sectional area | 85.0288 mm² · 167,806 circular mils |
| Resistance (copper, 20°C) | 0.2028 Ω/km · 0.0618 Ω/1000ft |
| Resistance (aluminum, 20°C) | 0.3325 Ω/km · 0.1013 Ω/1000ft |
| Ampacity — copper 60°C | 165 A |
| Ampacity — copper 75°C | 200 A |
| Ampacity — copper 90°C | 225 A |
| Ampacity — aluminum 75°C | 155 A |
| Weight (copper) | 761.858 kg/km · 511.944 lbs/1000ft |
| Weight (aluminum) | 229.578 kg/km · 154.269 lbs/1000ft |
| Closest IEC 60228 size | 95 mm² |
| Skin depth at 60 Hz | 8.531 mm |
| Type | Temperature | Description |
|---|---|---|
| THHN/THWN-2 | 90°C dry / 75°C wet | Most common for building wire |
| XHHW-2 | 90°C dry and wet | Cross-linked polyethylene, moisture resistant |
| USE-2 | 90°C | Underground service entrance |
| NM-B (Romex) | 90°C | Non-metallic sheathed cable for residential |
| UF-B | 60°C | Underground feeder, direct burial |
3/0 AWG copper is commonly used for 200A copper service entrances. NEC Table 310.16 rates it 200A at 75°C. It measures 10.405 mm in diameter with a 85 mm² cross-section.
Per NEC Table 310.16 (30°C ambient, no more than three current-carrying conductors), 3/0 AWG copper is rated 165A at 60°C, 200A at 75°C and 225A at 90°C. 3/0 AWG aluminum is rated 130A, 155A and 175A in the same columns. Above 100A, NEC 110.14(C) allows the 75°C column when terminations are rated 75°C.
Yes. 3/0 AWG aluminum is rated 155A at 75°C versus 200A for copper. Aluminum at this size is common for feeders, subpanels and service conductors (SER, USE-2, XHHW-2). Use AL-rated lugs, torque to the manufacturer’s spec and apply antioxidant compound where required.