motors. In accordance with 430.14(B),
open motors that have commutators
or collector rings shall be located or
protected so that sparks cannot reach
adjacent combustible material.
Section 110.21 was revised in the 2014
edition. The section—“Marking”—is the
same in the 2014 edition as it was in
the 2011 edition. The three sentences
that were in Section 110.21 are now in
110.21(A), and this subsection is now
titled “Manufacturer’s Markings.” In
accordance with 110.21(A), all electrical
equipment shall have a marking or label
that contains the manufacturer’s name,
trademark or other descriptive marking
by which the organization responsible for
the product can be identified. As stated
in the next sentence, other markings
that indicate voltage, current, wattage or
other ratings shall be provided as speci-
fied elsewhere in the Code. The marking
or label shall be of sufficient durability
to withstand the environment involved.
The only information required by this
section is a marking or label that iden-
tifies which organization is responsible
for the product. Other sections require
additional information such as voltage,
current and wattage to be marked on
the electrical equipment. For example,
in accordance with 430.7(A), the manu-
facturer’s name is just one of many items
that must be marked on a motor. Some of
the other items include rated volts and
full-load current; rated frequency and
number of phases (if an AC motor); rated
full-load speed; rated temperature rise
or the insulation system class and rated
ambient temperature; time rating; rated
horsepower (hp) if ⅛ hp or more; Code
letter or locked-rotor amperes (if an AC
motor rated ½ hp or more); and design
letter for B, C or D motors.
While 430.7(A) lists 15 items, not all of
them are required to be on every motor.
For example, if a motor is provided with
a thermal protector complying with
430.32(A)( 2) or (B)( 2), it shall be marked
“Thermally Protected” [430.7(A)( 13)].
This section has an alternative provision
for motors rated 100 watts (W) or less.
Thermally protected motors rated 100W
or less and complying with 430.32(B)( 2)
shall be permitted to use the abbreviated
marking “T.P.” See 430.7(A)( 1) through
(A)( 15) for a complete list of information
required to be marked on a motor (see
In the 2014 NEC, a new subsection
was added to 110.21, which covers field-applied hazard markings. Required
hazard signs and labels, such as the
required arc flash hazard warning
in 110.16, are in a number of places
throughout the Code. In accordance
with 110.21(B), where the NEC requires
caution, warning or danger signs or
labels, the labels shall meet all of the
requirements in 110.21(B)( 1) through ( 3).
While there are a number of locations
throughout the Code that require some
type of field or factory marking, not
every marking has to meet the requirements in 110.21(B).
For example, 110.24(A) pertains to
field marking certain equipment with
the maximum available fault current.
It does state the field marking(s) shall
be of sufficient durability to withstand
the environment involved but does
not specify the marking shall meet
the requirements in 110.21(B). Section 110.21(B) only applies to caution,
warning and danger signs. The first
requirement for field-applied hazard
markings is that the marking shall use
FIGURE 2 FIELD-APPLIED HAZARD MARKINGS
In accordance with 110.21(B), where the NEC requires caution, warning or danger signs
or labels, the labels shall meet all of the requirements in 110.21(B)( 1), ( 2) and ( 3).
In accordance with 110.21(B)( 1), the marking shall use effective words and/or colors and/or
symbols to adequately warn people of the hazard.
As stated in the informational note under 110.21(B)( 1), guidelines for suitable font sizes,
words, colors, symbols and location requirements for labels are in ANSI Z535.4 2011,
Product Safety Signs and Labels.
“Warning” indicates a hazardous situation and, if not avoided,
could result in death or serious injury if an accident occurs.
“Caution” indicates a hazardous situation and, if not avoided,
could result in moderate or minor injury.
“Danger” indicates a hazardous situation and, if not avoided,
will result in death or serious injury if an accident occurs.