705.10 Identification of Power Sources.

The labeling required in 705.10 is now required to indicate the emergency telephone numbers of any off-site entities servicing the power source systems.
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The labeling required in 705.10 is now required to indicate the emergency telephone numbers of any off-site entities servicing the power source systems.

Code Change Summary: New requirements to label the phone numbers of any off-site entities servicing the power source systems.

In the 2023 NEC®, a public input was accepted by the NFPA 1/ NEC® PV Joint Task Group with the purpose of aligning the labeling and marking requirements in the NEC® for interconnected power sources such as PV systems with those of the Fire Code (NFPA 1).

Section 11.12.2.1.5 in NFPA 1 has specific marking and labeling requirements pertaining to building mounted and building integrated PV systems which include a label adjacent to the main disconnect indicating the name and emergency telephone number of any company currently servicing the PV system.

In the 2023 NEC®, the revised labeling requirements for interconnected power sources in 705.10 will now reflect the language in the Fire Code.

In the 2023 NEC®, Section 705.10 requires permanent plaques, labels, or directories at each service equipment location, or at an approved readily visible location that provides the following information:

(1) The labeling shall denote the location of each power source disconnecting means for the building or structure.

See exception.

(2) The labeling shall indicate the emergency telephone numbers of any off-site entities servicing the power source systems.

(3) The labeling shall include the wording “CAUTION: MULTIPLE SOURCES OF POWER.” The marking shall comply with 110.21(B). 

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 2023 NEC® edition of NFPA 70.

2020 Code Language:

705.10 Identification of Power Sources. A permanent plaque or directory shall be installed at each service equipment location, or at an approved readily visible location. The plaque or directory shall denote the location of each power source disconnecting means for the building or structure and be grouped with other plaques or directories for other on-site sources. The plaque or directory shall be marked with the wording “CAUTION: MULTIPLE SOURCES OF POWER.” Any posted diagrams shall be correctly oriented with respect to the diagram's location. The marking shall comply with 110.21(B).

2023 Code Language:

705.10 Identification of Power Sources. Permanent plaques, labels, or directories shall be installed at each service equipment location, or at an approved readily visible location in accordance with the following:

(1) Denote the location of each power source disconnecting means for the building or structure.

See exception.

(2) Indicate the emergency telephone numbers of any off-site entities servicing the power source systems.

(3) Be marked with the wording “CAUTION: MULTIPLE SOURCES OF POWER.” The marking shall comply with 110.21(B).

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705.10 Identification of Power Sources.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

According to 705.10, which of the following is required to be labeled at each service equipment location, or at an approved readily visible location?

A: Contact information of the installer.
B: Phone numbers of local emergency services.
C: The emergency telephone numbers of any off-site entities servicing the power source systems.
D: Telephone numbers of all onsite maintenance personnel.
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