MECKLENBURG COUNTY
6/8/11
Land Use and Environmental Service Agency
Code Enforcement
ELECTRICAL CONSISTENCY MEETING
Code Consistency Questions
1. Is there a limit to the number of nonmetallic sheathed cables that can be pulled through
the same drilled or punched hole in a wooden joist?
Maybe and yes. Article 334.80 states:
Where more than two NM cables containing two or more current-carrying conductors are
installed, without maintaining spacing between the cables, through the same opening in wood
framing that is to be fire- or draft-stopped using thermal insulation, caulk, or sealing foam, the
allowable ampacity of each conductor shall be adjusted in accordance with Table
310.15(B)(2)(a) and the provisions of 310.15(A)(2), Exception, shall not apply.
Where more than two NM cables containing two or more current-carrying conductors are
installed in contact with thermal insulation without maintaining spacing between cables, the
allowable ampacity of each conductor shall be adjusted in accordance with Table
310.15(B)(2)(a).
2. Is an outlet box required on a metal post light at a residence? When installing a metal post
and lantern in a residential yard using UF cable is it required that the post be grounded?
An outlet box or handhole is not required in a pole 8 ft. or less where the supply wiring
method continues without splice to the splice at the post lantern (luminaire). You can pull the
UF cable through a hole drilled in the pole and up to the splice to the post head. 410.30(B)
and it’s Exception No.1.
Exception No. 2 allows this a pole without a handhole if the pole is 20 feet or less and has a
hinged base.
Yes, grounding of the metal pole is required (250.4(A)(4). If an ungrounded (hot) conductor
were to come in contact with and energize the metal pole, an equipment-grounding conductor
attached to the metal pole would carry the fault current back to the source and open the
overcurrent device for that circuit. If the metal pole were not grounded by an equipmentgrounding conductor the fault current energizing the metal pole would have to return to the
source through the earth. Due to the high resistance of the earth, enough current would not
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flow through the earth to open the overcurrent device in that circuit (250.4(A)(5). UF cable is
permitted to have an insulated or bare equipment-grounding conductor.
3. Is the sheath of Type NM cable permitted to extend more than ¼ in. inside the box? I’ve
seen boxes with 2 or 3 cable sheaths going into the box about 2 or 3 inches making it almost
impossible to install a device into the box without really jamming the cables back into the
box. The boxes are so narrow and deep that after the drywall is up you can’t get into the box
to cut back the sheath.
The NEC in 314.17(C) requires not less than ¼ in. of sheath inside the box and beyond any
cable clamp but does not specify a maximum length inside the box. However the box fill may
have to be calculated to prevent over-crowding the conductors due to the increased crosssectional area of the cable with sheath (see Table One, Note 9).
4. Where a 120-volt, 15- or 20-ampere receptacle outlet is installed at an outdoor open front
(damp location) covered refreshment area at an apartment building pool area is it required
that the receptacle be covered with an in-use cover or is a weatherproof cover of any type
required?
It only requires a weatherproof cover. See 406.8(A) that states, “A receptacle installed
outdoors in a location protected by the weather or in other damp locations shall have an
enclosure for the receptacle that is weatherproof when the receptacle is covered (attachment
plug cap not inserted and receptacle covers closed). A receptacle shall be considered to be in
a location protected from the weather where located under roofed open porches, canopies,
marquees, and the like, and will not be subjected to a beating rain or water runoff.” Also, new
for 2008 – All 15- and 20-ampere, 125- and 250-volt non locking receptacles in damp or wet
locations shall be a listed weather-resistant type. See both 406.8(A) and 406.8(B)(1).
5. What is the difference in a neutral and a grounded conductor in a 120/240, 3-wire, singlephase service?
See Article 100 for the definitions of grounded conductor, neutral and neutral conductor as
follows: “Neutral Conductor. The conductor connected to the neutral point of a system that is
intended to carry current under normal conditions.” Neutral Point. The common point on a
wye-connection in a polyphase system or midpoint on a single-phase, 3-wire system, or
midpoint of a single-phase portion of a 3-phase delta system, or a midpoint of a 3-wire, directcurrent system.” Also see the FPN under “Neutral Point” that states, “At the neutral point of
the system, the vectorial sum of the nominal voltages from all other phases within the system
that utilize the neutral, with respect to the neutral point, is zero potential.”
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6. Is a cord-connected filter pump for a storable pool allowed to be protected by a GFCI type
circuit breaker or is a GFCI receptacle type device required for such protection?
See 2008 NEC 680.31 for a revision to this section that states, “Cord-connected pool filter
pumps shall be provided with a ground-fault circuit interrupter that is an integral part of the
attachment plug or located in the power supply cord within 300 mm (12 in.) of the attachment
plug.
7. Please explain the boundaries of a damp and wet location as it pertains to porches
45⁰
Damp
Wet
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PEOPLE ● PRIDE ● PROGRESS ● PARTNERSHIPS
700 North Tryon Street • Charlotte, North Carolina 28202 • Fax (704) 336-3839
www.meckpermit.com