Code Change Summary: Section 300.7(D)(3) was revised to clarify that the warning ribbon requirement applies to both direct buried service conductors and raceways containing service conductors.

SME commentary: In the 2026 NEC^®, Section 300.7(D)(3) was revised to improve clarity by specifically adding “raceways containing service conductors” to the existing requirement for underground warning ribbons. The language now requires that both direct buried service conductors and service conductors installed in raceways, when buried at depths of 18 inches or more below grade and not encased in concrete, must have their location identified with a warning ribbon placed in the trench at least 12 inches above the underground installation.

Historically, this requirement (previously 300.5(D) in the 2023 NEC) has existed in the Code for underground service conductors, but the wording did not explicitly mention “service conductors in raceways”. Although the parent text in 300.5(D) referred broadly to “conductors and cables,” which many interpreted as including raceways, the absence of direct language created confusion among code users. Some AHJs enforced the rule only for direct buried conductors, while others extended the requirement to include underground service raceways, leading to inconsistent enforcement across jurisdictions.

By adding the words “raceways containing service conductors,” the 2026 NEC^® removes this ambiguity. The revision makes it clear that warning ribbons are required regardless of whether the service conductors are direct buried cables or installed in a raceway. This clarity helps ensure that all underground service wiring methods are adequately identified to prevent accidental damage during future excavation.

The warning ribbon serves an important safety function. When properly installed 12 inches above the buried wiring, the ribbon provides a clear visual indicator to anyone digging in the area that electrical service conductors are below. This early warning can prevent inadvertent strikes with excavation equipment that could otherwise result in service outages, expensive repairs, or severe injury. The inclusion of raceways is critical because the physical protection offered by a raceway does not eliminate the need for identification. Excavation equipment can easily damage both direct buried cables and rigid raceways when their presence is not marked.

It is also worth noting that the depth and warning ribbon requirements only apply when the conductors or raceways are not encased in concrete. Installations protected by concrete encasement do not require a warning ribbon, since the concrete itself provides both physical protection and location identification.

This revision is consistent with the NEC’s overall emphasis on practical safeguarding. By addressing both direct buried service conductors and service raceway installations explicitly, the Code ensures consistent application of safety measures. The update also reduces potential disputes in the field by giving AHJs clear and enforceable language.

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:

300.5(D) Protection from Damage. Conductors and cables shall be protected from damage in accordance with 300.5(D)(1) through (D)(4).

300.5(D)(3) Service Conductors. Underground service conductors that are not encased in concrete and that are buried 18 inches or more below grade shall have their location identified by a warning ribbon that is placed in the trench at least 12 inches above the underground installation.

2026 Code Language:

300.7(D) Protection from Damage. Conductors and cables shall be protected from damage in accordance with 300.7(D)(1) through 300.7(D)(4).

300.7(D)(3) Service Conductors and Raceways. Direct buried service conductors and raceways containing service conductors that are not encased in concrete and that are buried 18 inches or more below grade shall have their location identified by a warning ribbon that is placed in the trench at least 12 inches above the underground installation.