Overview

Surge protective devices (SPDs) are essential for preventing damage from power surges, which can peak at values exceeding 10kA or 10kV and originate from both external and internal sources. The 2023 NEC has expanded SPD requirements to include dormitory units, guest rooms and suites in hotels and motels, and patient sleeping rooms in nursing homes and limited-care facilities, broadening protection and reliability across more environments. Additionally, a new subsection, 230.67(E), specifies that SPDs must have a nominal discharge current rating of at least 10kA.

Applying the 2023 Code

Power surges are brief voltage or current spikes that typically last only a few milliseconds but can peak at values exceeding 10kA or 10kV. These surges can be triggered by external events like lightning strikes or short circuits, as well as internal sources such as variable speed drives, contactor switching, or capacitor switching. The rapid increase to peak voltage or current followed by a slower decline can cause severe damage to electronic devices, disrupt sensitive equipment, and create safety hazards. Surge protective devices (SPDs) are crucial for protecting modern electronics and safety devices, such as AFCIs, GFCIs, and smoke/carbon monoxide detectors, by absorbing or redirecting excess voltage, preventing damage and maintaining functionality.

Previous NEC versions provided requirements for installing surge protection devices (SPDs) in Section 230.67. These requirements included the need for SPDs on all services supplying dwelling units. The SPDs must be either integral to the service equipment or located immediately adjacent to it, with an exception allowing SPDs to be located at downstream distribution equipment if they are not placed in the service equipment. The SPD devices must be Type 1 or Type 2, and all requirements will apply even when the service equipment is replaced. The 2023 NEC has expanded these requirements to include additional locations beyond dwelling units. Surge protection is now mandatory for services supplying dormitory units, guest rooms and suites in hotels and motels, and patient sleeping rooms in nursing homes and limited-care facilities. Additionally, a new subsection, 230.67(E), was added to specify that SPDs must have a nominal discharge current rating of at least 10kA. These updates aim to enhance the protection and reliability of electrical systems across a broader range of residential and care environments.

What’s New for the 2023 NEC?

The table below presents a comparison between the 2020 NEC and the 2023 NEC regarding Section 230.67.