Table 3.75: Table 3.75 provides 3-phase, 3-wire and 3-phase, 4-wire feeder sizes based on the rating of the overcurrent protective device. CIRCUIT SIZE SCHEDULE NOTES: S1. UNLESS OTHERWISE INDICATED, ...

three phase systems without a neutral conductor are known as "3-wire" systems, while those that include a neutral wire are known as "4-wire." The fourth neutral wire is often added when manufacturers ...