MECKLENBURG COUNTY
Land Use & Environmental Services Agency
Code Enforcement
4/11/12 ELECTRICAL CONSISTENCY MEETING
Code Consistency Questions
1. Consistency question- Switch with fuses over top of a transformer. Is this a violation of
110-26?
Yes, 110.26(A) 3 states:
(3) Height of Working Space. The work space shall be clear and extend from the grade, floor,
or platform to the height required by 110.26(E). Within the height requirements of this
section, other equipment that is associated with the electrical installation and is located above
or below the electrical equipment shall be permitted to extend not more than 150 mm (6 in.)
beyond the front of the electrical equipment.
2. The local sheet metal shop fabricates pull and junction boxes as well as wireways for us.
Can we use a non-listed J-box, wireway or auxiliary gutter for equipment grounding? Are
wireways listed for grounding?
No, A wireway is a raceway (see Article 100 for definition) and there are specific construction
specifications for their construction in Article 376, however 250.118(13) & (14) specifically
require that these would have to be listed for grounding.
376.100 Construction.
(A) Electrical and Mechanical Continuity. Wireways shall be constructed and installed so that
adequate electrical and mechanical continuity of the complete system is secured.
(B) Substantial Construction. Wireways shall be of substantial construction and shall provide a
complete enclosure for the contained conductors. All surfaces, both interior and exterior, shall
be suitably protected from corrosion. Corner joints shall be made tight, and where the
assembly is held together by rivets, bolts, or screws, such fasteners shall be spaced not more
than 300 mm (12 in.) apart.
(C) Smooth Rounded Edges. Suitable bushings, shields, or fittings having smooth, rounded
edges shall be provided where conductors pass between wireways, through partitions, around
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bends, between wireways and cabinets or junction boxes, and at other locations where
necessary to prevent abrasion of the insulation of the conductors.
(D) Covers. Covers shall be securely fastened to the wireway.
3. A 1½ HP swimming pool pump motor is installed as part of a swimming pool installation at
a residence. The pump is 240-volt, single-phase rated and protected by a 25 amp rated
circuit breaker which calculates to be 250-percent of the motor FLA which is normal with
430.52(C)(1) and Table 430.52. Question -Does this pool pump require GFCI protection be
installed for personnel protection?
The full load current for a 240 volt, single phase pool pump motor is 10 amps at 230 volts
with the maximum rating or setting of motor branch circuit short circuit and ground fault
protective device (inverse time circuit breaker) at 250% could be rated at 25 amps. The GFCI
protection requirement only applies to outlets supplying pool pump motors connected to single
phase, 120 through 240 volts branch circuits rated at 15 or 20 amperes based on 680.21(C)
but not at 25 amperes so the answer is no.
680.21 Motors, (A) Wiring Methods. The wiring to a pool motor shall comply with (A)(1)
unless modified for specific circumstances by (A)(2), (A)(3), (A)(4), or (A)(5). (C) GFCI
Protection. Outlets supplying pool pump motors connected to single-phase, 120 volt through
240 volt branch circuits, rated 15 or 20 amperes, whether by receptacle or by direct
connection, shall be provided with ground fault circuit-interrupter protection for personnel.
Using the Code definition of the term outlet is important to correctly apply this requirement.
The term outlet includes a point on the wiring system where a receptacle is installed to supply
a cord-and plug-connected pool pump motor and also includes a point on the wiring system
from where the branch circuit is run directly to the pool pump motor often referred to as a
“hard-wired” installation.
4. What NEC Section covers underwater installations? A property owner has a large pond
with an island that he wishes to run a feeder to. 2) Is it acceptable to lay nonmetallic
conduit on the bottom of the pond? 3) If so how do we secure it? 4) Could UF or USE cable
be used without a raceway?
1) See new 2005 NEC Article 682 where the scope reads, “This article applies to the
installation of electrical wiring for, and equipment in and adjacent to, natural or artificially
made bodies of water not covered by other articles in this Code, such as but not limited to
aeration ponds, fish farm ponds, storm retention basins, treatment ponds, irrigation
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(channels) facilities.” 2) Maybe, but check with manufacturer, as water “should not damage”
but submersion is not a listed “uses permitted” in Article 352 for rigid nonmetallic raceways
such as Schedule 40 or Schedule 80 PVC. First, see the definition of “wet location” in Article
100, which states, “Installations under ground or in concrete slabs or masonry in direct
contact with the earth; in locations subject to saturation with water or other liquids, such as
vehicle washing areas; and in unprotected locations exposed to weather.” Note “submersion”
is not addresses as a “wet location” per the use of the NEC.
See Article 352, Part II.
Installation and more specifically 352.10 Uses Permitted, which states, “The use of RNC shall
be permitted in accordance with 352.10(A) through (H), plus look at the FPN, which states,
“Extreme cold may cause some nonmetallic conduits to become brittle and therefore more
susceptible to damage from physical contact.” Under 352.10(D) Wet Locations, it states, “RNC
shall be permitted in portions of dairies, laundries, canneries, or other wet locations and in
locations where walls are frequently washed, the entire conduit system including boxes and
fittings used therewith shall be installed and equipped so as to prevent water from entering
the conduit. All supports, bolts, straps, screws, and so forth, shall be of corrosion-resistant
materials or be protected against corrosion by approved corrosion-resistant materials.” Note it
states nothing about “submersion” nor is there permission to submersion in extreme cold
water where ice may be a substantial issue. Also see 352.12(C), Uses Not Permitted, that
states, “(C) Physical Damage. Where subject to physical damage unless identified for such
use.” Also, note that Section 310.8(C) that addresses conductors for general wiring in wet
locations does not address submersion.
3) See 352.30 Securing and Supporting, which
states, “RNC shall be installed as a complete system as provided in 300.18 and shall be
fastened so that movement from thermal expansion or contraction is permitted. RNC shall be
securely fastened and supported in accordance with 352.30(A) and (B).” Section 330.30(A)
states, “RNC shall be securely fastened within 900 mm (3 ft) of each outlet box, junction box,
device box, conduit body, or other conduit termination. Conduit listed for securing at other
than 900 mm (3 ft) shall be permitted to be installed in accordance with the listing.” Section
330.30(B) states, “RNC shall be supported as required in Table 352.30(B). Conduit listed for
support at spacings other than as shown in Table 352.30(B) shall be permitted to be installed
in accordance with the listing. Table 352.30(B) Support of Rigid Nonmetallic Conduit (RNC)
states”
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Conduit Size
Metric Designator
16–27
35–53
63–78
91–12
155
Maximum Spacing
Between Supports
Trade Size
½–1
1¼–2
2½–3
3½–5
6
mm or m
ft
900 mm
1.5 m
1.8 m
2.1 m
2.5 m
3
5
6
7
8
4) See “340.10 Uses Permitted for UF cable, which states, “Type UF cable shall be
permitted as follows: (1) For use underground, including direct burial in the earth. For
underground requirements, see 300.5. Therefore, submersion is not addressed as a
permissible use nor is it prohibited. (3) For wiring in wet, dry, or corrosive locations
under the recognized wiring methods of this Code. Also, per 338, Service-Entrance
Cable: Type SE and USE, submersion is not addressed as a permissible use nor is it
prohibited. Therefore, an installer should contact the manufacturer of the cable for
advise on using either product as a submersible wiring method. Also, it should be
noted that the FPN stating, “The “Uses Permitted” is not an all-inclusive list.” Was not
included in either Article 340 or 338 for Type UF cable or Type SE or USE cable
respectively. However, there are listed cables and cable assemblies for “submersion”
and there is no prohibition for using a Rigid Nonmetallic Conduit such as Schedule 40
or Schedule 80 PVC as a protective sleeve for this type of cable or cable assembly.
5. Is an isolated equipment-grounding conductor required to be connected to boxes,
wireways, etc where the isolated equipment-grounding conductor passes through such boxes
and enclosures as the exception to 250.148 that references 250.146(D) only references
panelboards?
This question points out a revision to 250.146(D) by adding a new last sentence that states, “
Where installed in accordance with the provisions of this new section, the equipment
grounding conductor shall also be permitted to pass through boxes, wireways, or other
enclosures without being connected to such enclosures. Also, note that the former second
word, “required”, to this section has been replaced with the word, “installed”, as the NEC does
not require isolated grounding receptacles with such installed receptacles being a design issue.
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6. Are replacement receptacles required to be “Tamper Resistant”?
No, See 406.3(D)
7. Per 110.26(C)(3), if an entrance to a work space has a door(s) it is required that the
door(s) opens in the direction of egress and be equipped with locking devices that open
under simple pressure. Would this requirement apply to multiple doors in line with an egress
path and where does this requirement stop – at an exit corridor, at the front door to the
building, etc?
This question points out a revision to 110.26(C)(2) that states, “Where equipment rated 1200
A or more that contains overcurrent devices, switching devices, or control devices is installed
and there is a personnel door(s) intended for entrance to and egress from the working space
less than 7.6 m (25 ft) from the nearest edge of the working space, the door(s) shall open in
the direction of egress and be equipped with panic bars, pressure plates, or other devices that
are normally latched but open under simple pressure.” Also, note that this provision has been
moved into a section of it its own so that it is understood this requirement is a stand alone
requirement and not depend on or a part of other requirements.
8. 1) Can a grounding electrode conductor to a concrete-encased electrode be smaller than 4
AWG copper. 2) If yes, is physical protection required, and 3) if yes, what type of physical
protection is required?
1) Yes, the grounding electrode conductor from a concrete encased electrode to a service can
be as small as a No. 8 copper but does not have to be larger than No. 4 based on 250.66(A)
and the accompanying Table 250.66 2) Section 250.64(B) provides protection requirements
for grounding electrode conductors as follows: “A 6 AWG grounding electrode conductor that
is free from exposure to physical damage shall be permitted to be run along the surface of the
building construction without metal covering or protection where it is securely fastened to the
construction; otherwise, it shall be in rigid metal conduit, intermediate metal conduit, rigid
nonmetallic conduit, electrical metallic tubing, or cable armor.” 3) Grounding electrode
conductors smaller than 6 AWG shall be in rigid metal conduit, intermediate metal conduit,
rigid nonmetallic conduit, electrical metallic tubing, or cable armor.
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9. 1) What is a branch-circuit overcurrent device, and 2) is it different from a feeder-circuit
overcurrent device?
1) 2008 NEC, Article 100 has a new definition: “A device capable of providing protection for
services, feeder, and branch circuits and equipment over the full range of overcurrents
between its rated current and its interrupting rating.” 2) No, it is not different.
10. 525.11 states that where multiple services or other power systems or both supply loads
at a carnival or fair where the loads (rides, buildings, structures, etc) are separated less than
12-feet shall be bonded to the same grounding electrode system. Where do you find the
requirements for minimum size of the bonding conductor and the type metallic material that
is acceptable as the required bonding conductor?
See revised 525.11 for the 2008 NEC that states, “Where multiple services or separately
derived systems, or both, supply portable structures, the equipment grounding conductors of
all the sources of supply that serve such structures separated by less than 3.7 m (12 ft) shall
be bonded together at the portable structures. The bonding conductor shall be copper and
sized in accordance with table 250.122 based on the largest overcurrent device supplying the
portable structures, but not smaller than 6 AWG.”
11. What
is the electrical classification of an unventilated pit in a jiffy lube?
511.2 Definitions.
Major Repair Garage. A building or portions of a building where major repairs, such as engine
overhauls, painting, body and fender work, and repairs that require draining of the motor
vehicle fuel tank are performed on motor vehicles, including associated floor space used for
offices, parking, or showrooms. [30A:3.3.12.1]
Minor Repair Garage. A building or portions of a building used for lubrication, inspection, and
minor automotive maintenance work, such as engine tune-ups, replacement of parts, fluid
changes (e.g., oil, antifreeze, transmission fluid, brake fluid, air-conditioning refrigerants),
brake system repairs, tire rotation, and similar routine maintenance work, including associated
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floor space used for offices, parking, or showrooms. [30A:3.3.12.2]
511.3 Area Classification, General.
Where Class I liquids or gaseous fuels are stored, handled, or transferred, electrical wiring and
electrical utilization equipment shall be designed in accordance with the requirements for Class
I, Division 1 or 2 hazardous (classified) locations as classified in accordance with 500.5 and
500.6, and this article. A Class I location shall not extend beyond an unpierced wall, roof, or
other solid partition that has no openings. [30A:8.3.5, 8.3.2]
(A) Parking Garages. Parking garages used for parking or storage shall be permitted to be
unclassified.
FPN: For further information, see NFPA 88A-2007, Standard for Parking Structures, and NFPA
30A-2008, Code for Motor Fuel Dispensing Facilities and Repair Garages.
(B) Repair Garages, With Dispensing. Major and minor repair garages that dispense motor
fuels into the fuel tanks of vehicles, including flammable liquids having a flash point below
38°C (100°F) such as gasoline, or gaseous fuels such as natural gas, hydrogen, or LPG, shall
have the dispensing functions and components classified in accordance with Table 514.3(B)(1)
in addition to any classification required by this section. Where Class I liquids, other than
fuels, are dispensed, the area within 900 mm (3 ft) of any fill or dispensing point, extending in
all directions, shall be a Class I, Division 2 location.
(C) Major Repair Garages. Where flammable liquids having a flash point below 38°C (100°F)
such as gasoline, or gaseous fuels such as natural gas, hydrogen, or LPG, will not be
dispensed, but repair activities that involve the transfer of such fluids or gases are performed,
the classification rules in (1), (2), and (3) shall apply.
(1) Floor Areas.
(a)
Ventilation Provided. The floor area shall be unclassified where there is mechanical
ventilation providing a minimum of four air changes per hour or one cubic foot per minute of
exchanged air for each square foot of floor area. Ventilation shall provide for air exchange
across the entire floor area, and exhaust air shall be taken at a point within 0.3 m (12 in.) of
the floor.
(b)
Ventilation Not Provided. The entire floor area up to a level of 450 mm (18 in.) above
the floor shall be classified as Class I, Division 2 if the ventilation does not comply with
511.3(C)(1)(a).
(2) Ceiling Areas. Where lighter-than-air gaseous fueled vehicles, such as vehicles fueled by
natural gas or hydrogen, are repaired or stored, the area within 450 mm (18 in.) of the ceiling
shall be considered for classification in accordance with (a) and (b).
(a)
Ventilation Provided. The ceiling area shall be unclassified where ventilation is
provided, from a point not less than 450 mm (18 in.) from the highest point in the ceiling, to
exhaust the ceiling area at a rate of not less than 0.3 m3/min/m2 (1 cfm/ft2) of ceiling area at
all times that the building is occupied or when vehicles using lighter-than-air gaseous fuels are
parked below this area.
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(b)
Ventilation Not Provided. Ceiling areas that are not ventilated in accordance with
511.3(C)(2)(a) shall be classified as Class I, Division 2.
(3) Pit Areas in Lubrication or Service Room. Any pit, belowgrade work area, or subfloor work
area shall be classified as provided in (a) or (b).
(a)
Ventilation Provided. The pit area shall be a Class I, Division 2 location where there is
mechanical ventilation providing a minimum of six air changes per hour.
(b)
Ventilation Not Provided. Where ventilation is not provided in accordance with
511.3(C)(3)(a), any pit or depression below floor level shall be a Class I, Division 1 location
that extends up to the floor level.
(D) Minor Repair Garages. Where flammable liquids having a flash point below 38°C (100°F)
such as gasoline, or gaseous fuels such as natural gas or hydrogen, will not be dispensed or
transferred, the classification rules in (D)(1), (D)(2), and (D)(3) shall apply to the lubrication
and service rooms.
(1) Floor Areas. Floor areas in minor repair garages without pits, belowgrade work areas, or
subfloor work areas shall be unclassified. Where floor areas include pits, belowgrade work
areas, or subfloor work areas in lubrication or service rooms, the classification rules in (a) or
(b) shall apply.
(a)
Ventilation Provided. The entire floor area shall be unclassified where there is
mechanical ventilation providing a minimum of four air changes per hour or one cubic foot per
minute of exchanged air for each square foot of floor area. Ventilation shall provide for air
exchange across the entire floor area, and exhaust air shall be taken at a point within 0.3 m
(12 in.) of the floor.
(b)
Ventilation Not Provided. The floor area up to a level of 450 mm (18 in.) above any
unventilated pit, belowgrade work area, or subfloor work area and extending a distance of 900
mm (3 ft) horizontally from the edge of any such pit, belowgrade work area, or subfloor work
area, shall be classified as Class I, Division 2.
(2) Ceiling Areas. Where lighter-than-air gaseous fuels (such as natural gas or hydrogen) will
not be transferred, such locations shall be unclassified.
(3) Pit Areas in Lubrication or Service Room. Any pit, belowgrade work area, or subfloor work
area shall be classified as provided in (a) or (b).
(a)
Ventilation Provided. Where ventilation is provided to exhaust the pit area at a rate of
not less than 0.3 m3/min/m2 (1 cfm/ft2) of floor area at all times that the building is
occupied, or when vehicles are parked in or over this area and where exhaust air is taken from
a point within 300 mm (12 in.) of the floor of the pit, belowgrade work area, or subfloor work
area, the pit shall be unclassified. [30A:7.4.5.4. Table 8.3.1]
(b)
Ventilation Not Provided. Where ventilation is not provided in accordance with
511.3(D)(3)(a), any pit or depression below floor level shall be a Class I, Division 2 location
that extends up to the floor level.
(E) Modifications to Classification.
(1) Specific Areas Adjacent to Classified Locations. Areas adjacent to classified locations in
which flammable vapors are not likely to be released, such as stock rooms, switchboard
rooms, and other similar locations, shall be unclassified where mechanically ventilated at a
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rate of four or more air changes per hour, or designed with positive air pressure, or where
effectively cut off by walls or partitions.
(2) Alcohol-Based Windshield Washer Fluid. The area used for storage, handling, or dispensing
into motor vehicles of alcohol-based windshield washer fluid in repair garages shall be
unclassified unless otherwise classified by a provision of 511.3. [30A:8.3.5, Exception]
12. 240.83(D) indicates that "SWD" marked circuit breakers are for switching fluorescent
lighting and that “HID” marked circuit breakers are for switching fluorescent and highintensity discharge lighting. Two Questions: 1) Are circuit breakers marked "SWD" suitable
for switching incandescent as well as fluorescent lighting? 2) Are circuit breakers marked
“HID” suitable for switching incandescent as well as fluorescent and high intensity discharge
lighting?
See 240.83(D) and 110.3(B). Yes. The NEC does not prohibit or restrict the use of a circuit
breaker to switch incandescent lighting loads. Circuit breakers marked “SWD” can be used for
switching both incandescent and fluorescent lighting loads. There are no limitations on this
application in the UL guide card information (DIVQ) for molded case circuit breakers. 2) See
240.83(D) and 110.3(B). Yes. Circuit breakers marked “HID” can be used for switching highintensity discharge lighting loads, fluorescent lighting loads and incandescent lighting loads.
SWD and HID breakers are subjected to additional endurance and temperature testing to
ensure that they will be robust enough for regular switching of these types of loads.
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