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Author(s): Derek Vigstol. Published on May 1, 2019.

In Compliance | NEC

Labeling electrical equipment: What, why, and where to turn for guidance


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These days, every time we turn around it seems there’s another label applied to electrical equipment—warning labels, information labels, manufacturer’s labels, and more. The front of switchgear is starting to look like grandma’s refrigerator, plastered with school pictures of the grandkids. No wonder there is growing confusion among facility managers as to what labels they need, which labels must be regularly updated, and why the labels are there in the first place.

Some labels are required by the installation code. The 2017 edition of NFPA 70®, National Electrical Code®, requires a few different labels to be applied to certain equipment. (For the purposes of this discussion, I’m not including the required manufacturer labels or equipment required to be “labelled” as defined in Article 100.) For starters, arc flash hazard warning labels are required by 110.16. For most equipment, this is simply a label warning qualified persons that there is a potential arc flash hazard present. This applies to equipment such as switchgear, switchboards, panelboards, motor control centers, industrial control panels, disconnects, and meter sockets in other than dwelling units that are likely to require servicing while energized. While this means you don’t need a large orange WARNING sticker on your panel at home, there might be multifamily dwelling equipment that this does apply to. This marking is permitted to be field or factory marked.

This requirement is modified slightly when the equipment in question is service equipment. All service equipment in other than dwelling units is required to be field marked with the available fault current and the date that the calculation was made per 110.24. For larger service equipment, 1200A and over, 110.16(B) requires, in addition to the arc flash warning, that equipment be marked with nominal system voltage, available fault current, the clearing time of the service OCPD based upon the available fault current at the equipment, and the date the label was applied.

If this information looks familiar, it might be because much of it is also used in helping determine certain levels of protection in NFPA 70E®, Standard for Electrical Safety in the Workplace®. For that reason, there is an exception to 110.16(B) that allows for other warning labels applied in accordance with another acceptable industry practice, such as NFPA 70E.

Speaking of NFPA 70E, equipment that is likely to require servicing or examination while energized is also required by 130.5(H) to be marked with a label. Since NFPA 70E is a voluntary standard that can be used to comply with the requirements of OSHA, this label isn’t necessarily required at the time of installation, unless the intent is to follow the exception mentioned above. However, the information required by this label is invaluable in protecting employees who could be exposed to electrical hazards. Regardless if your electrical safety program is based on NFPA 70E, equipment labeled with essential information to keep workers safe just makes sense.

Similar to the label required for large service equipment in the NEC®, the information required by the label in NFPA 70E is intended to provide information aimed at protecting workers. At a minimum, these labels must contain the nominal system voltage, the arc flash boundary, and at least one of the following: the available incident energy and the corresponding working distance or the arc flash PPE category found in the PPE category tables, the minimum arc rating of clothing, or the site-specific level of PPE.

While the NEC is not retroactive and doesn’t require labels to be updated, there is a requirement to put the date that the available fault current was calculated on the label so that if changes have been made in the system, the calculation can be updated as well. There is also an exception to the requirement in NFPA 70E that says this label does not have to be updated unless something has changed that would render the label inaccurate. The data contained on the label must be reviewed at least every five years to verify its accuracy.

No matter which label we’re talking about or the document that requires it, the common denominator is that labels are required because they enhance the safety in our facilities and for our employees by communicating much-needed information. They are an integral part of an electrical safety program and must be treated accordingly. Having a plan on what information they must contain and when they must be reviewed for accuracy can help ease the pain of information overload and confusion within the electrical industry.

DEREK VIGSTOL is an NFPA technical lead, Electrical Tech Services.