|NEC Questions and Answers
|By Mike Holt for ECM Magazine
Q1. Does the Code require a local disconnect on the primary side of a
A1. No, just overcurrent protection in accordance with
Q2. Can you tell me where the Code rule is about operating
handles for switches and circuit breakers used as switches not being more than 6
ft 7 in. above the floor or working platform?
A2. This rule is contained
in 404.8(A), which also requires switching devices to be located so that they
may be operated from a readily accessible place. However, exception 2 allows
switching devices to be above this height, if installed adjacent to motors,
appliances, or other equipment.
Q3. Is there a NEC requirement that an
equipment grounding conductor be installed in PVC conduits?
352.60 states that where equipment grounding (bonding) is required by Article
250, a separate equipment grounding (bonding) conductor shall be installed in
So the key is if equipment grounding (bonding) is required by
Article 250, and the installation is nonmetallic conduit, then an equipment
grounding (bonding) conductor must be installed.
But the exceptions to
352.60 permit the grounded (neutral) conductor to be used for bonding at the
following locations [250.142(A)]:
(1) On the supply side or within the
enclosure of the service disconnecting means [250.24(B)].
(2) On the supply
side or within the enclosure of the disconnecting means for separate buildings
(3) On the supply side or within the enclosure of the
disconnecting means of separately derived systems [250.30(A)(1)].
What is the NEC color code requirement for 120/208V and 277/480V
A4. The NEC does not contain color code requirement for
ungrounded conductors, except 110.15 requires the high-leg conductor from a
120/240 4-wire delta-connected system to be identified with the color orange.
The grounded (neutral) conductors must be identified with the color white or
gray in accordance with 200.6 and equipment grounding (bonding) conductors must
be bare, or identified in the color green, or green with a yellow strip if
insulated in accordance with 250.119.
Q5. We are encountering situations
in high-rise condos where they are installing very small laundry closets,
sometimes in bathrooms! The combo washer/dryer receives power from a single 30A,
240V outlet. Am I still required to install the 20A receptacle circuit for the
A5. Yep, the 20A receptacle circuit is still required
[210.11(C)(2)] because someone might replace the 30A combo washer/dryer with a
unit that requires a 20A receptacle.
Q6. Is it a code violation to
install a 3-phase main breaker panel for a single-phase service and a 3-phase
breaker for a single-phase panel? I would say it is not listed for this purpose;
therefore this would be a violation.
A6. There is nothing in the NEC that
would prohibit this installation unless the these parts were installed in
violation of manufacturers instructions [110.3(B)].
Q7. I am handling an
automobile claim where one of our insured's struck an electrical wire that was
attached to a building. The height of our insured's tractor-trailer is 13'6. I
am trying to determine if the NEC lists the height requirement for electrical
wiring above parking lot/streets. I feel I can deny this loss based upon the
fact the height of the wire was below the standard. I just need to verify where
I can find that information.
A7. The minimum height of overhead conductor
spans over public streets, alleys, roads, and parking areas subject to truck
traffic shall not be less than 18 ft [225.18].
Q8. I strongly feel that a
120V outdoor receptacles for sump pump equipment in an industrial plant be
plugged into a GFCI receptacle for personnel safety. Is there a NEC article that
addresses it directly or indirectly?
What Code rule requires a receptacle
for drinking fountains in commercial/industrial setting to be GFCI
A8. Sorry, but the NEC does not require GFCI protection for
any of these applications.
Q9. I remember reading somewhere that an
inspector couldn't make a contractor chip out the footer to create a concrete
encased electrode. Is there such a ruling and if so could you quote it. It seems
to me that chipping out the footer creates a building code violation.
A9. No the NEC does not require that a concrete encased electrode be
made accessible. If the concrete is already poured, then it's simply not
available. I base my comments on the NFPA Formal Interpretation 78-4, which is
contained in the NEC Handbook.
Reference: Article 250.50
Question: Is it
the intent of 250.50 that reinforcing steel, if used in a building footing, must
be made available for grounding?
Issue Edition: 1978
Issue Date: March 1980
Q10. Can a duplex
receptacle be used as a splice point for other outlets in the circuit? I was
under the impression that each box was to have a pigtail for the receptacle and
not use the receptacle as a splice means.
A10. This is a product standard
issue, not a NEC requirement. Wiring devices are listed for this purpose.
However, the continuity of a grounded (neutral) conductor for multiwire branch
circuits shall not depend on device connections [300.13(B)].