If nine Level II EVSEs require a feeder on a 3-phase system, what is the minimum ampacity of the copper feeder conductors needed?

To determine the minimum ampacity of the copper feeder conductors required for nine Level II Electric Vehicle Supply Equipment (EVSE) units on a 3-phase system, it's essential to understand the power and demand characteristics of Level II chargers.

Level II EV chargers typically supply power at a rate of up to 80 amps per charger. However, in practical applications, not all chargers may operate at maximum capacity simultaneously due to demand factors. Therefore, the National Electrical Code (NEC) provides guidelines on calculating demand for electric vehicle charging stations, which often includes factors for diversity in the load.

The calculation starts by estimating the total load when all chargers might be in use. For nine Level II chargers, calculating the total potential load involves multiplying the maximum current by the number of chargers, yielding up to 720 amps (nine chargers x 80 amps each). However, due to demand load calculations, you would apply demand factors outlined in the NEC.

Typically, for a reasonable estimate in three-phase systems, you could expect that not all chargers would continuously draw their full load. A common demand factor could be around 0.4 or lower, leading to a calculated demand of around 288 amps (720 amps x 0.4).

Now, when sizing