74 ELECTRICALCONTRACTOR | JAN. 16 | WWW.ECMAG.COM
effective words, colors or symbols to
adequately warn people of the hazard.
An informational note under 110.21(B)
( 1) provides help in determining the
physical appearance of the sign or label.
As stated in the note, guidelines for suit-
able font sizes, words, colors, symbols
and location requirements for labels are
in ANSI Z535.4 2011, Product Safety Signs
and Labels. A danger sign indicates a haz-
ardous situation, which, if not avoided,
will result in death or serious injury if an
accident occurs. This signal word is to be
limited to the most extreme situations. A
warning sign indicates a hazardous situ-
ation, which, if not avoided, could result
in death or serious injury if an accident
occurs. A caution indicated a hazardous
situation, which, if not avoided, could
result in minor or moderate injury if an
accident occurs (see Figure 2).
The second requirement for field-applied hazard markings states the
label shall be permanently affixed to the
equipment or wiring method and shall
not be handwritten. Even if a permanent marker is used, hand writing the
words “Danger,” “Warning” or “Caution”
shall not be permitted. While this is not
permitted, certain information can be
written on the sign or label.
In accordance with the exception to
110.21(B)( 2), portions of labels or markings that are variable, or that could be
subject to changes, shall be permitted
to be handwritten and shall be legible.
In accordance with 110.21(B)( 3), the
label shall be of sufficient durability to
withstand the environment involved.
The informational note under this section references an ANSI standard that
provides guidelines for the design and
durability of safety signs and labels for
application to electrical equipment.
The document referenced in this informational note is the same document
referenced in the informational note in
As previously mentioned, a number
of sections throughout the Code require a
caution, warning or danger sign (or label).
Instead of each of those sections containing the requirements for field-applied
hazard warnings, those sections say the
marking shall meet the requirements in
110.21(B). For example, 110.16 requires an
arc flash hazard warning. As stated in the
second sentence, the marking shall meet
the requirements in 110.21(B) and shall be
located so as to be clearly visible to qualified people (see Figure 3).
Next month’s column continues
the discussion of electrical installation
MILLER, owner of Lighthouse Educational Services, teaches custom-tailored seminars
on the National Electrical Code and NFPA 70E. He is the author of “Illustrated Guide to
the National Electrical Code” and “Electrician’s Exam Prep Manual.” He can be reached at
615.333.3336 and www.charlesRmiller.com. Connect with Charles R. Miller on LinkedIn.
CODE IN FOCUS
FIGURE 3 PERMANENT AND OF SUFFICIENT DURABILITY
Besides field-applied hazard marking signs and labels warning people of hazards by
using effective words and/or colors and/or symbols, the signs and labels shall also
meet two more requirements in 110.21(B).
In accordance with 110.21(B)( 2), the field-applied hazard marking shall be permanently
affixed to the equipment or wiring method and shall not be handwritten.
In accordance with 110.21(B)( 3), the label shall be of sufficient durability to withstand
Arc Flash Hazard