Overview

Modern Electric Vehicle Supply Equipment (EVSE) technologies benefit from advanced electronic controls, including sophisticated load management and adjustable settings. Section 625.42 outlines the requirements for determining EVSE device

ratings. The 2023 NEC update to this section allows Energy Management Systems (EMS)

to dynamically control the total load on a service or feeder, whether the EMS is part of a single unit or a multi-piece system. Additionally, the code now permits adjustable settings on both fixed

and cord-connected EVSEs, expanding installation options and enhancing the flexibility

of these devices. These updates improve EVSE’s ability to manage electrical demand and

adapt to various installation environments, enhancing overall system performance and safety.

Applying the 2023 Code

Modern EVSE technologies incorporate electronic control functions such as load management and adjustable load settings, surpassing the capabilities of traditional EVSE technology, which only offered open-loop electrical charging. Load management involves an Energy Management System (EMS) that dynamically monitors and controls the total current draw of multiple EV chargers connected to a single branch circuit or feeder, ensuring that the combined load does not exceed the circuit’s capacity. This is essential in environments like commercial parking lots where multiple EV chargers operate simultaneously. On the other hand, adjustable load settings allow individual EV chargers to be configured to draw less power, making them suitable for installations with limited electrical capacity. This static adjustment helps a single charger operate within the system’s limits, avoiding the need for costly upgrades to the branch circuit.

Previous NEC versions required EVSE to be rated to handle the load, treating EV charging loads as continuous. Service and feeders had to be sized accordingly, and load management systems were restricted to the maximum load allowed by the system. Adjustable settings were allowed only on fixed-in-place equipment, with adjustments needing to be durable and aligned with manufacturer instructions, and access to these adjustments had to be restricted to prevent unauthorized changes. The 2023 NEC updates refined these requirements: it now permits Energy Management Systems (EMS) to control the maximum equipment load on a service and feeder. EMS can be integrated into a single piece of equipment or a multi-piece system. EVSE with restricted access to ampere adjusting means is still allowed, but adjustments must adhere to manufacturer instructions and be durable. Additionally, the code now supports adjustable settings on both fixed-in-place and cord-connected EVSE, expanding installation flexibility.

What’s New for the 2023 NEC?

The table below presents a comparison between the 2020 NEC and the 2023 NEC regarding Section 625.42.