Q. According to 110.16, certain information is required on the label when marking switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers. To be compliant with this section of the Code, which of the following examples best illustrates the written text of 110.16? The arc flash analysis determined that the incident energy at an industrial control panel is 6 cal/cm2. The industrial control panel will require troubleshooting, as well as testing for voltage by qualified persons.
A) Beware. Shock boundary 36 in.
B) Hot. Energized. Energized work permit required. Job briefing not required for testing and troubleshooting.
C) Warning. Arc flash and shock hazard. Appropriate PPE required.
D) Warning. Job briefing required before starting work. Limited approach boundary.
Explanation: In part, the text of 110.16 states that switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers, in other than dwelling occupancies, shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located as to be clearly visible to qualified persons before examining, adjusting, servicing, or maintaining the equipment. The text does not require incident energy values to be marked on the label.
Although it’s important to follow the requirements of NFPA 70E, Sections 130.2 and 130.3, it must be noted that the reference to NFPA 70E in the 2005 NEC is in the form of a fine print note (FPN). At minimum, the answer given in (C) above would be adequate. However, it’s permissible to provide more information, if desired.
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at [email protected].