Code Change Summary: New Section 550.51(E) requires surge protection when reconnecting service equipment to a replacement mobile or manufactured home.

SME commentary: In the 2026 NEC^®, a new requirement was added in Section 550.51(E) to address surge protection for replacement mobile and manufactured homes. This addition mirrors the structure and intent of the surge protective device (SPD) requirements already found in Section 230.67 for dwelling units. Now, when existing service equipment is reconnected to a replacement mobile or manufactured home, the service shall be provided with a surge protective device in accordance with 230.67.

Prior to this revision, the NEC^® required surge protection only when new service equipment was installed, but did not explicitly extend this protection to situations where existing service equipment was reconnected to a new or replacement manufactured home. This omission often created a gap in protection for homes moved or replaced within existing mobile home parks, where the original service equipment remained in place. The new language closes that gap, ensuring that replacement homes receive the same level of surge protection as newly installed services.

Section 230.67, first introduced in the 2020 NEC^®, established a baseline requirement that all dwelling unit services be protected by an SPD. That section requires installation of a Type 1 or Type 2 SPD located in or immediately adjacent to service equipment. Section 230.67(D) further requires that when service equipment is replaced, the surge protection requirements of 230.67 now apply to the new service replacement.

By referencing 230.67, the new 550.51(E) provision ensures mobile and manufactured homes receive equivalent protection from transient overvoltages caused by lightning, utility switching, or other disturbances on the distribution system. These homes are considered dwelling units under the NEC^® and are just as susceptible to surge-related damage as other dwellings or areas addressed in 230.67.

This change also provides clarity and consistency for enforcement by the authority having jurisdiction (AHJ). When a mobile or manufactured home is replaced or reconnected to an existing service, inspectors can now verify surge protection as part of the reconnection process, similar to how it is applied in site-built residential dwellings. The revision aligns Article 550 with Article 230 requirements and reinforces the NEC’s ongoing effort to standardize surge protection across many types of dwelling-type occupancies.

Ultimately, this update ensures that both new and replacement manufactured housing installations are equally safeguarded against voltage surges that could otherwise damage appliances, electronic systems, and life-safety equipment within the home.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2026 NEC^® edition of NFPA 70.

2023 Code Language:

The code section did not exist.

2026 Code Language:

N 550.51(E) Replacement Home. When existing service equipment is reconnected to a replacement mobile or manufactured home, the service shall be provided with a surge protective device in accordance with 230.67.