Code Change Summary: Revised code language clarifies where field-applied hazard labels must be located for switchboards, switchgear, and panelboards.

SME commentary: In the 2026 NEC^®, previous Section 408.3(F) was renumbered as 408.10(F) and revised to improve clarity on the placement of field-applied hazard markings for switchboards, switchgear, and panelboards. The updated rule now requires any caution signs or labels specified in 408.10(F)(1) through (5) to comply with 110.21(B) and be at a readily accessible location on the front of the enclosure. This change strengthens visibility and accessibility requirements so that critical hazard warnings can be easily seen without the need to remove equipment covers or open doors.

Prior editions of the NEC^® required specific cautionary labels but did not identify where those labels were to be placed. As a result, installers often located markings on interior panels or surfaces that could only be seen after removing protective barriers. The revised 2026 language eliminates that ambiguity by making it explicit that all required warning labels must be readily visible on the front of the equipment enclosure.

The labels specified for switchboards, switchgear, and panelboards in 408.10(F)(1) through 408.10(F)(5) below still retain their original rules and require caution labels as follows:

408.10(F)(1) High-Leg Identification for a 4-wire, delta-connected system:

CAUTION _____ PHASE HAS _____ VOLTS TO GROUND

408.10(F)(2) Ungrounded ac Systems:

CAUTION UNGROUNDED SYSTEM OPERATING — _____ VOLTS BETWEEN CONDUCTORS

408.10(F)(3) Impedance Grounded Systems:

CAUTION: IMPEDANCE GROUNDED SYSTEM OPERATING — _____ VOLTS BETWEEN CONDUCTORS AND MAY OPERATE — _____ VOLTS TO GROUND FOR INDEFINITE PERIODS UNDER FAULT CONDITIONS

408.10(F)(4) Ungrounded dc Systems:

CAUTION: UNGROUNDED DC SYSTEM OPERATING — _____ VOLTS BETWEEN CONDUCTORS

408.10(F)(5) Resistively Grounded dc Systems:

CAUTION: DC SYSTEM OPERATING — _____ VOLTS BETWEEN CONDUCTORS AND MAY OPERATE — _____ VOLTS TO GROUND FOR INDEFINITE PERIODS UNDER FAULT CONDITIONS

The 2026 update does not alter the wording of those caution statements; rather, it specifies their visibility and accessibility to promote consistency in the field.

The retained cross-reference to 110.21(B) further requires that labels must:

• Be of sufficient durability to withstand the environment involved
• Warn of the hazards using effective words, colors, symbols, or any combination thereof
• Be permanently affixed to the equipment
• Not be handwritten (except for variable values that may be subject to change)

From a practical standpoint, this revision improves safety and inspection efficiency. Electricians and maintenance personnel can now confirm required system identification and voltage warnings at a glance, without having to open the equipment. Inspectors benefit as well, since the front-mounted label ensures compliance can be verified visually and quickly.

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:

408.3(F) Switchboard, Switchgear, or Panelboard Identification. A caution sign(s) or a label(s) provided in accordance with 408.10(F)(1) through (F)(5) shall comply with 110.21(B).

2026 Code Language:

408.10(F) Switchboard, Switchgear, or Panelboard Identification. Caution signs or labels provided in accordance with 408.10(F)(1) through 408.10(F)(5) shall comply with 110.21(B) and be at a readily accessible location on the front of the enclosure.