What size wire do I need for 100 amp service?
2-gauge
When it comes to the lines connecting master and secondary panels, where the line will carry as much as a full 100 amps, use a 2-gauge non-metallic sheathed electrical cable. The cable must contain one or two hot wires depending on your needs, one neutral wire, and one ground wire. Each wire should be 2-gauge in size.
How many amps will #4 copper wire carry?
Wire Size and Amp Ratings
| Wire Size | 75°C (167°F) | |
|---|---|---|
| AWG | (mm²) | Copper |
| 6 | (13.3) | 65 |
| 4 | (21.2) | 85 |
| 3 | (26.7) | 100 |
