Electrical Contractor - September 2017

As an Arizona electrical contractor doing an electrical installation, I needed a union for a rigid metal conduit connection to a piece of electrical equipment so the conduit could be disconnected and the equipment replaced easily. I sent an apprentice to the supply house to pick one up. He came back empty-handed and told me the counter person said they did not have a union. That surprised me so much that I called the supply house to inquire why they did not have any in stock. The counter person told me he did not have any “unions” in stock but did have “Ericksons.” He said the apprentice should learn the electrical nomenclature.

Technically, a union is a three-piece coupling intended for use with rigid metal conduit or intermediate metal conduit and is used in place of a regular coupling so the raceway can be taken apart. “Erickson” is a trade name for a union fitting. Needless to say, I was very upset with the counter person for causing a delay and an extra trip.

NEC Article 410 covers lampholders and luminaires; however, do you screw a bulb or lamp into a lampholder? Why is it called a “lampholder” in the industry and the NEC, while the major home improvement industry use “bulb”? If you ask a salesperson for lamps in a home improvement store, he or she will refer you to the table and floor lamp department. Many electricians also use the term “bulb,” but the NEC does not.

Technically, regarding the nomenclature
of an incandescent or fluorescent lamp,
the bulb is the glass part that encloses
the filament for the incandescent lamp
or contains the gases in the fluorescent
tubular lamps. The NEC uses the phrase
“fluorescent tubular lamp” and “incan-
descent lamp.”
Probably the most frequent misuse
of terms is when dealing with ground-
ing and bonding. Many electricians in
the field will use the term “ground wire.”
Which wire does “ground wire” refer to?
There are many different “wires” or, as
I like to call them, conductors. When
asked about specific information on a
“ground wire,” most electricians will say
the “green wire.”
Equipment grounding conduc-
tors can be bare, covered or insulated.

Individually covered or insulated equip-
ment grounding conductors will have a
continuous outer finish that is either
green or green with one or more yel-
low stripes. The covering of a covered
equipment grounding conductor has not
been tested for its insulation character-
istics. A grounding electrode conductor
of the wire type can be solid or stranded,
insulated, covered, or bare, as the last
sentence of 250.62 notes. There are
many different types of grounding
conductors, and then we start talking
about grounded conductors, which is an
entirely different issue with other rules
for color coding and insulating.
Another major difference between
field nomenclature and the NEC deals
with photovoltaic modules, panels and
arrays. Many electricians and even
manufacturers use the term “panel” to
describe a photovoltaic module.
Section 690.2 provides definitions
for each of these terms. A module is
defined as “a complete, environmentally
protected unit consisting of solar cells,
optics, and other components, exclu-
sive of tracker, designed to generate DC
power when exposed to sunlight.” A
panel is defined as “a collection of mod-
ules mechanically fastened together,
wired, and designed to provide a field-
installable unit.” An array is defined as
“a mechanically integrated assembly of
module(s) or panel(s) with a support
structure and foundation, tracker, or
other components, as required, to form
a DC or AC power-producing unit.”
Is there an issue about how these
terms are used? A panel, as noted in the
definition, is a collection of modules.
Wherever possible, use the correct
terminology or nomenclature, especially
when ordering materials. And for Pete’s
sake, don’t belabor an apprentice for
not knowing the relationship between
common and proper terminology. A
disconnect in nomenclature can cost
someone time and money.
Magic Words

Does electrical terminology mean anything?

TERMINOLOGY IS THE VOCABULARY OF TECHNICAL TERMS AND USAGES appropriate to a particular trade, science or art. Does it matter what we call something in the National Electrical Code (NEC) Is there a difference in what something is called in the field or what a component is called in trade slang or an industry term versus the technical term?

OD E is a lead engineering associate for Energy & Power Technologies at Underwriters Laboratories Inc. and can be reached at 919.949.2576 and Mark. C. Ode@ul.com. AR