NEC 2023

Surge Protection

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Quick links: | Article Surge protection  | NEC Requirement | NEC 2023 code change/Intention | Rationale for change

Article

230.67 Surge Protection
215.18 Feeders
225.42 Outside Branch Circuits and Feeders

NEC requirement

Services that supply the following are required to have surge protection installed within the service equipment:

1. Dwelling units

2. Dormitory units

3. Guest rooms and guest suites of hotels and motels

4. Areas of nursing homes and limited-care facilities used exclusively as patient sleeping rooms

There is an exception that permits surge protection to not be installed in service equipment—when surge protection is installed in the next-level distribution equipment downstream toward the load.

In addition to the requirements for services, there are also requirements for feeder applications. Equipment that supplies the same occupancy types listed in 230.67 that is not service equipment but fed from a feeder is also required to be equipped with a surge protective device (SPD). Sections 215.18 and 225.42 address feeder applications.

Figure 1 illustrates a common situation on multi-family dwelling unit applications where service equipment and meter centers and dwelling unit panelboards/loadcenters are employed. In this case, each dwelling unit panelboard is required to have an SPD because of the requirements in 215.18, as these panelboards are at the end of a feeder that serves the dwelling unit. The meter center also requires an SPD because of the requirements in 215.18 as it too is at the end of a feeder that serves the dwelling unit. The service equipment requirement found in 230.64 could be omitted with surge protection if leveraging the exception to 230.64 as long as all downstream equipment directly fed from the service equipment has an SPD installed. In this case, panels L1 and M1, which are common area panelboards and not required to include an SPD, present the need to place an SPD in the service equipment if an SPD is not included in these panelboards

NEC 2023 code change/intention

The intent is to address an application where providing an SPD as part of the requirements found in Article 230 would not provide adequate surge protection. The requirements ensure an SPD is located as close to the structures being served as possible.

Rationale for change

During the 2023 Code cycle, it was pointed out that in some cases the surge device can be quite a far distance away from the service equipment. For example, service equipment could be located at the road at the end of a very long driveway. In those cases, the surge device is better for the application when equipped at the dwelling unit and not at the service. In these instances, the service equipment will provide a feeder to the electrical distribution equipment at the structure being served. The provisions found in Article 215 and Article 225 mandate that surge protection be installed at the end of these feeders and the exception in Article 230 recognizes that when the
first-level distribution equipment downstream from the service is equipped with an SPD, there is no need for surge protection at the service equipment.

Explore the crucial updates in surge protection codes

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Surge Protection

Article

NEC requirement

NEC 2023 code change/intention

Rationale for change

Explore the crucial updates in surge protection codes

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