in cable assemblies
When using Type MC or other cable
assemblies for lighting in a commercial
occupancy, we are required to identify the
white or gray conductor used as a switch
leg as a hot conductor. This means we
have to stop and place tape on the white
or gray conductor at each switch location.
Why is this a requirement? All electricians
understand how switch legs function.
The general rule in Section 200.7(A)
requires conductors with white or
gray insulation to be used only for the
grounded circuit conductor unless otherwise permitted in 200.7(B) or (C).
Section 200.7(C) provides permission
to use conductors with white or gray
insulation where it is permanently reidentified as an ungrounded conductor.
Permitted methods of re-identification
include the use of marking tape, painting or other effective means.
It is important to note that this
re-identification of the white or gray
insulation must occur at the switch location and all locations where the gray or
white conductor is visible and accessible. The most common method to
re-identify is with marking tape (other
than white, gray or green) that must
encircle the conductor. This requirement also mandates that, where the
white or gray conductor is used as a
switch leg, the conductor may be used
for the supply to the switch. However,
it is never permitted as a return from
the switch to a lighting fixture or other
The reason for the marking is to
identify the white or gray conductor as
an ungrounded conductor. It should be
noted that this permissive requirement
is not limited to switch legs.
When applying the rules for ground-fault
circuit interrupter (GFCI) protection of
receptacles in dwelling-unit basements,
Section 210.8(A)( 5) refers to portions or
areas of the basement not intended as
habitable rooms. How do I determine
the intent of a room? My neighbor
recently had her basement finished by a
local contractor. The electrical inspector
required all of the 125-volt (V) receptacles
to be GFCI-protected. He said the room
was not habitable as per the building code.
Rooms do not have intent as to how they
will be occupied. However, we can look
at a room or space and determine how
the builder intended the space to be
occupied and other potential uses for
the room. The 2017 NEC no longer contains a reference to storage areas, work
areas and similar areas as being unfinished spaces. The requirement for GFCI
protection in Section 210.8(A)( 5) now
simply requires GFCI protection of all
125V, single-phase, 15- and 20-ampere
(A) receptacles in unfinished portions
or areas of the basement not intended as
This ties us directly to the building
code definition of “habitable space,”
which is spaces for living, sleeping, eating
or cooking. That sounds easy, but it’s not
unless you are well versed in building-code requirements.
The requirements for habitable space
include, but are not limited to, minimum
ceiling height, ventilation/windows
based on a percentage of floor area,
minimum room size, lighting and egress.
The inspector apparently saw an issue
with the finished basement and determined it did not meet the requirements
for a habitable space, per the building
code. While a basement area may seem
completely finished as a living space, it
may not meet all building code requirements for a habitable space.
Branch circuit or a feeder?
Perhaps you can provide an answer to
a debate we have been having over the
correct NEC term for conductors. Per the
contract drawings, we wired multiple
large industrial heaters with 4 AWG
copper conductors protected at 100A
from a panelboard to a fused disconnect
(with current limiting fuses rated at
100A) at the equipment location. We
then installed 4 AWG copper conductors
in flexible metal conduit from the fused
disconnect to the heaters. Since there
is no outlet, are the conductors from
the panelboard to the fused disconnect
located at the equipment branch-circuit
conductors or feeders?
The conductors from the panelboard to
the fused disconnect at the equipment
are feeders. The conductors from the
fused disconnect to the equipment are
branch-circuit conductors. Article 100
defines branch-circuit conductors as
the conductors between the final overcurrent device protecting the circuit and
There is an outlet in this installation.
As defined in Article 100, an outlet is a
point on the wiring system at which
current is taken to supply utilization
equipment. The point at which a branch
circuit is hard-wired to utilization equipment is an outlet by definition.
Basements and More
Jim Dollard has an extensive background in codes and standards.
If you have a query about the National Electrical Code (NEC), Jim
will help you solve it. Questions can be sent to
Answers are based on the 2017 NEC.
CODEFAQS BY JIM DOLLARD Rooms do not have
intent as to how they will
be occupied. However,
we can look at a room
or space and determine
how the builder intended
the space to be occupied
and other potential uses
for the room.