When installing multiple EVSEs, what factor should be considered to determine the appropriate feeder size?

When installing multiple Electric Vehicle Supply Equipment (EVSE) units, considering the total line current across phases is critical to determine the appropriate feeder size. This approach ensures that the combined electrical demand of all connected EVSE units is accommodated efficiently and safely.

The total line current across phases takes into account the cumulative load that each EVSE may draw simultaneously when multiple vehicles are charging. This is vital because each unit can have different charging rates and may not operate at full capacity all at the same time, but planners must prepare for the worst-case scenario where all units could be charging simultaneously.

Selecting the feeder size based solely on the highest amperage unit, on the other hand, may lead to inadequate capacity because it does not factor in the combined current draw of multiple units. Similarly, focusing only on the voltage level or the length of the feeder could overlook the need for sufficient current-carrying capability, which is critical for preventing voltage drops and ensuring efficient operation. Evaluating the total line current provides a comprehensive assessment, ensuring that the installed infrastructure can handle the full load and operate safely.