MECKLENBURG COUNTY
Land Use and Environmental Services Division
Code Enforcement
Memo
Date:
To:
From:
Re:
July 11, 2011
All customers
Jim Bartl, Director of Code Enforcement
2012 NC State Building Code effective dates
In the June 14 meeting of the NC Building Code Council (BCC), the Council confirmed the transition dates for the
new 2012 NC State Building Code family. While the BCC set a constant effective date for all codes except
electric, the transition period varies as follows:
• The 2012 NC Building, Fire Prevention, Mechanical, Plumbing and Fuel Gas Codes will have a
transition period of September 1, 2011 through March 1, 2012.
• The 2012 NC Residential Code and NC Energy Conservation Code will have a transition period of
January 1, 2012 through March 1, 2012.
Regarding the 2011 NC Electrical Code, ten letters of objection were filed with the NC Rule Review
Commission, which automatically throws the issue into the NC General Assembly’s 2012 session.
Consequently, we will continue using the 2008 edition of the NC Electrical Code, and we do not anticipate a
switch to the 2012 NC Electrical Code until summer 2012, if even at that time.
It is also important to note that, the 2012 NC Residential Code will include residential requirements for electrical,
mechanical and plumbing trade installations (whereas previous NC Residential Codes referenced the individual
electrical, mechanical and plumbing codes). Customers with permits issued through March 1, 2012, under the
2009 NC Residential Code will continue to refer to the 2009 NC Mechanical Code, 2009 NC Plumbing Code and
2008 NC Electrical Code, as in the past.
Regarding the absolute cutoff date for use of the 2009 NC State Building Code family, given the long transition
periods and the lengthy advance notice provided by the BCC, we see no reason to extend this with an additional
grace period beyond March 1, 2012. Consequently, permits issued after March 1, 2012 must comply with the 2012
NC State Building Code family (except as noted above regarding the electrical code).
It is very important that professionals closely monitor their work to carefully determine when a project’s design
basis must switch to the new 2012 NC State Building Code family to comply with the above transition periods and
the Department’s policy regarding same. While state law requires the Department to issue a permit on any project
in compliance with the effective code, the burden is on the owner’s team to estimate when your permit will be
issued. Projects not permitted by March 1, 2012 must comply with the 2012 NC State Building Code family,
regardless of when they entered the system for permitting.
Feel free to contact me, Directors Gene Morton or Patrick Granson, plan review or field inspection managers, or
the Code Administrators if you have questions on the effective dates of the 2012 NC State Building Code family.
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Land Use and Environmental Services Agency
APRIL, MAY JUNE
2011
BUILDING
SECOND QUARTER 2011
Commercial Consistency
Land Use and Environmental Service Agency
(Code Enforcement)
May Q&A 2011
General:
1.
(Q) Can you use a parallel approach for sinks?
(A) Yes, Section 606.2 of ANSI A117.1 allows for a parallel approach for sinks
in kitchens that do not provide a cook top or conventional range such as a
break room.
2. (Q) What do you do when a N is found between two occupancies in Table 508.3.3?
(A) For separated mixed occupancies you must go to Table 706.3.9 with no
reduction for sprinklers.
3. (Q) In type B units if an Option B bathroom is provided do the other bathrooms have
to be accessible?
(A) No. Only if an Option A type is provided do all the bathrooms have to be
Type A.
4. (Q) Can the flip up section of a bar be used as the accessible part of the bar?
(A) No
5. (Q) Does lighting have to be provided when a space is returned to an unoccupiable
space?
(A) Yes, lighting shall be provided in accordance with section 1006.2 for egress
purposes
6. (Q) Can a spiral stair be used for egress?
(A) Yes in accordance with section 1009.8 and only in areas allowed by that
section.
Commercial Consistency
Land Use and Environmental Service Agency
(Code Enforcement)
June Q&A 2011
General:
1.
(Q) What happens when two walls with different fire ratings intersect?
(A) The fire rating of the higher rated wall must be fully maintained.
2. (Q) What must be done at the top of a shaft that encloses an egress stair?
(A) The shat walls must extend to the roof deck or the shaft must be capped off
with a cap with the same rating as the shaft and be independent of the roof
structure.
3. (Q) On accessible stairs does the nosing have to be of a different color from the
tread?
(A) Per ANSI 117.1 section 504.5 the leading 2” of the tread shall have visual
contrast of light on dark or dark on light.
4. (Q) Where can van accessible spaces be located in a parking deck?
(A) In multi level parking decks all of the van accessible spaces may be located
on the ground level.
5. (Q) When is an ambulatory stall required?
(A) When there are 6 or more water closets and urinals located in a single toilet
room.
6. (Q) When is a accessible unisex toilet room required in an assemble or mercantile
occupancy?
(A) Where there is an aggregate of six or more required male and female water
closets.
Residential Consistency
Land Use and Environmental Service Agency
(Code Enforcement)
April Q&A 2011
General:
1.
(Q) Is the floor system on an accessory building required to be pressure treated?
(A) Yes, when the girders are less than 12 above ground and the joists and sub
floor are less than 18; above the ground.
2. (Q) Are the party walls between town houses treated as exterior walls.
(A) Yes, they must be braced as exterior walls. If method 5 is used then they
must be inspected before they are taped and mudded.
3. (Q) What type of fire retardant wood must be used on town house roof sheathing?
(A) The sheathing must be pressure treated it cannot be a surface applied
coating.
4. (Q) When is a permit required for roofing replacement?
(A) A permit is not required for roofing replacement when the cost is less than
$5,000.00 and it is like for like. If the type of covering is changed then a
permit is required even if the cost is less than &5,000.00.
5. (Q) Where are vents required for crawl foundations?
(A) A vent is required at 3’-0” from the corners in each direction.
6. (Q) If I remove a chimney I can leave the fireplace open for decoration.
(A) No, if the chimney is removed the fire box must be closed off or otherwise
clearly shown that it is not a working fireplace
Land Use and Environmental Services Agency
APRIL, MAY, JUNE
2011
ELECTRICAL
SECOND QUARTER 2011
4/13/11
MECKLENBURG COUNTY
Land Use and Environmental Service Agency
Code Enforcement
ELECTRICAL CONSISTENCY MEETING
Code Consistency Questions
1. A fluorescent fixture hangs 15 feet below a ceiling. Can I use a cord to connect power to
the fixture? Does the fixture need a disconnect at the ceiling? Can the fixture be wired
directly into a junction box? Can I wire tie the cord to the support chains that hold the
fixture?
Yes, No, maybe, Yes: 410.30, 410.73(G)Exc. 3: The use of a flexible cord to supply
fluorescent fixtures is allowed by 410.30 provided the requirements of
(C)(1)(1) & (2) are met. These include the luminaries being located directly below the outlet,
the cord be visible its entire length and not subject to strain or damage, and be terminated in
an attachment plug, or be part of a listed assembly. 410.73(G) exc. 3 allows an accessible
plug and receptacle to be permitted to serve as the disconnecting means required by
410.73(G). The cord could only be directly wired into a junction box if part of a listed
assembly with a strain relief and canopy 410.30(C)(2) While 400.8 does not allow cord to be
attached to building surfaces the exception to (4) does allow an approved means of
attachment to relieve strain.
2. Is a QO Square D breaker ok to use as a dc disconnect for a platform lift? Nothing on the
breaker indicates it is ok for dc voltage, but the information supplied with the breaker
indicates it may be used for dc voltage less than 48v. Does this sound ok?
The UL White Book in DIVQ says, under Ratings; "A circuit breaker is marked AC or DC or
both AC and DC." Then going to the Marking Guide for Molded Case Circuit Breakers it says
under Voltage Rating, "If the voltage rating does
not include the words "ac" or "dc," the breaker is rated for both ac and dc voltages." This
means, with an absence of marking on the breaker it is suitable for AC or DC use.
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3. Section 690.4(B) on Solar Photovoltaic Systems, talks about “other systems” not being
allowed in the same raceway. The question is whether or not a 120vAC feed from the house
for the “tracking motor” of the array can be in the same raceway as the 360vDC from the
panels to the house? Is this part of the “system”? Some thought the system to be only the
‘DC voltage side’ and others thought anything to do with the ‘Project’ would apply.
No. NEC 690.4(B) states: Photovoltaic source circuits and photovoltaic output circuits shall not be
contained in the same raceway, cable tray, cable, outlet box,junction box, or similar fitting as feeders,
or branch circuits of other systems, unless the conductors of the different systems are separated by
partitions or are connected together. The photovoltaic source circuit is the circuits between the
modules and from modules to the common connection point(s) of the dc system. The photovoltaic
output circuit is the circuit conductors between the photovoltaic source circuits(s) and the inverter or
dc utilization equipment. Neither of these circuits would have anything to do with the 120v AC feed
for the tracking motor.
4. Is it permissible to terminate copper-clad aluminum conductors to 15 and 20 amp rated
receptacles?
Maybe, if allowed by receptacle listing. The UL Whitebook states as follows:
RECEPTACLES FOR PLUGS AND
ATTACHMENT PLUGS (RTRT)
TERMINALS
Terminals of 15 and 20 A receptacles not marked ‘‘CO/ALR’’ are for use with copper and copper-clad
aluminum conductors only. Terminals marked ‘‘CO/ALR’’ are for use with aluminum, copper and copper-clad
aluminum conductors.
Terminals of receptacles rated 30 A and above not marked ‘‘AL-CU’’ are for use with copper conductors
only.
Terminals of receptacles rated 30 A and above marked ‘‘AL-CU’’ are for use with aluminum, copper and
copper-clad aluminum conductors.
Terminals marked ‘‘75 C’’ may be wired using the ampacities for conductors rated 75°C as well as
conductors rated 60°C in Table 310.16 of the NEC.
Terminals of the wire-binding screw, setscrew, or screw-actuated back wired clamping types are suitable for
use with both solid and stranded building wires.
Screwless terminal connectors of the conductor push-in type (also known as ‘‘push-in-terminals’’) are
restricted to 15 A branch circuits and are for connection with 14 AWG solid copper wire only. They are not
intended for use with aluminum or copper-clad aluminum wire, 14 AWG stranded copper wire, or 12 AWG solid
or stranded copper wire.
Single and duplex receptacles rated 15 and 20 A that are provided with more than one set of terminals for
the connection of line and neutral conductors have been investigated to feed branch-circuit conductors
connected to other outlets on a multi-outlet branch circuit, as follows:
•
Back wire (screw actuated clamp type) terminations with multiple wire access holes used concurrently
to terminate more than one conductor
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•
Side wire (binding screw) terminals used concurrently with their respective push-in (screwless)
terminations to terminate more than one conductor
•
Single and duplex receptacles rated 15 and 20 A that are provided with more than one set of terminals
for the connection of line and neutral conductors have not been investigated to feed branch-circuit
conductors connected to other outlets on a multi-outlet branch circuit, as follows:
•
Side wire (binding screw) terminal with its associated back wire (screw actuated clamp type) terminal
•
Multiple conductors under a single binding screw
•
Multiple conductors in a single back wire hole
•
Duplex receptacles rated 15 and 20 A that are provided with break off tabs may have those tabs
removed so that the two receptacles may be wired in a multi-wire branch circuit.
5. My house has a vaulted ceiling with a lot of can lights installed. The insulation process was
to install a spray foam product throughout the joist area. This process pretty much enveloped
all the can lights. The inspector said this was not allowed as the foam would not allow heat
to dissipate and the foam material was not evaluated for what it might do to the can
assembly. I pointed out that these can lights are all energy qualified and IC rated assemblies.
Isn’t this OK?
No it isn’t OK. UL White Book IEZX, and 410.116(A)(2) for 2008 NEC. As the inspector
explained, these are not evaluated by a testing laboratory for being in contact with any
insulating product beside batt style or loose fill (blown – in) insulation.
6. Building B is powered by a 60 amp feeder from building A. The two buildings are 10 feet
apart. Can one pair of ground rods be used as the grounding electrode for both buildings?
Would this be considered a ground path similar to a metal water pipe between the two
buildings? Does it matter if it is a three- wire or four- wire feeder?
Yes, it is OK to use the same ground rods to meet the requirements of 250.32. Yes it is a
parallel path and you have to install a “4-wire system”. Note: in 2008 you always have to
install a “4 wire system” for new construction.
7. We have a homeowner who sub contracted his own well guy. They decided to install a 240
volt 3 h/p motor and the owner "forgot" to tell us. The problem is the well guy ran a 12-2
from the well head to the house. (He states he dropped a #8 down the well to the pump but
we have not yet been able to verify that ). The pump is drawing 22 amps, as the well itself is
300 feet deep, the run from the well head is 100 feet, and then another 75 feet from where
it enters the dwelling to the breaker box. So we have a situation where there is a total of 175
feet where a #12 wire is installed feeding this pump. Can we install a 25 amp breaker on
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this? Are we allowed to install a 30 ampere breaker? We told our builder the well wiring
should have been run in a #10. Of course, the well guy says otherwise and insists that using
the motor tables we can up size the over current protection.
You are dealing with a motor, my guess 3 horsepower single-phase? Based on
Table 430.248 the FLA is 17 and given the distance the voltage drop probably gets the 22
amps you are measuring. Let's start with the 17 amps. Section 240.4 (G) deals with
overcurrent protection and sends us to Article 430 for motors. Part IV says we can provide
protection in accordance with the Table 430.52 and given a circuit breaker this allows up to
250% of the FLA or 17X2.5= 42.5 Amperes which cannot be exceeded. This indicates that we
could use a 40 Ampere breaker. Let's go back to the conductor in Section 430.22 where the
ampacity shall be not less than 125% of the FLA. 17X1.25 = 21.25 Amperes. From here we go
back to the ampacity table in 310.16 and we need a conductor that is capable of carrying
21.25 Amperes indefinitely. A #12 conductor is good for 25 Amperes at 75 Deg C which meets
all of our criteria. Yes a 25 Ampere circuit breaker is acceptable. You could go as high as 40
Amperes. I agree with you that a #10 conductor would be more appropriate but the #12 is
legal. The voltage drop can be calculated based on conductor lengths and the FLA of the
motor.
8. Could you advise me on the proper mounting height for electrical panels where
accessibility may be required?
Accessibility for this issue is addressed in Chapter 11 of the NCBC; it states:
1101.2 Design. Buildings and facilities shall be designed and constructed to be accessible in
accordance with this code and ICC A117.1.
1109.13 Controls, operating mechanisms and hardware. Controls, operating mechanisms and
hardware intended for operation by the occupant, including switches that control lighting and
ventilation and electrical convenience outlets, in accessible spaces, along accessible routes or
as parts of accessible elements shall be accessible.
ICC/ANSI A117.1 section 309.2 and 309.3. Section 309.2 requires a clear floor space
complying with Section 305 of A117.1 shall be provided. 309.3 requires that operable parts
shall be placed within one or more of the reach ranges specified in Section 308. Section 308 is
divided into 2 sections – Forward Reach and Side Reach. 308.2.1 - Where a forward reach is
unobstructed, the high forward reach shall be 48 inches maximum and the low forward reach
shall be 15 inches minimum above the floor. 308.2.2 addresses obstructed reach range. NEC
110.26 would not permit an obstruction in front of an electrical panel. 308.3.1 – Where a clear
floor space allows a parallel approach to an element and the side reach is unobstructed, the
high side reach shall be 48 inches maximum and the low side reach shall be 15 inches
minimum above the floor. Therefore circuit breaker heights for Type A and Type B units would
be required to be
installed between 15 and 48 inches above the floor. Type A and B units are covered in
Chapter 10 of ANSI A117.1 standards. This chapter covers 20 pages in the book. I will not go
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through it here. Have your architect or building inspector designate which units are required
to be accessible and install the panels accordingly.
9. I am installing a fire alarm system in a hospital addition. I am a sub-contractor for the
main electrical contractor. Do I have to pull a separate permit for the fire alarm?
No. If the fire alarm contractor is working FOR the main electrical contractor (a subcontract), and the main electrical contractor is responsible for all electrical work, then
the fire alarm contractor would not need a separate permit.
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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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MECKLENBURG COUNTY
5/11/11
Land Use and Environmental Service Agency
Code Enforcement
ELECTRICAL CONSISTENCY MEETING
Code Consistency Questions
1. Will the department accept the building steel in the penthouse of a high rise Type I
building as a concrete encased electrode? We have no reason to believe that it is not an
effective ground. Others have used it in the past. We have measured the resistance through
the steel from the penthouse to the main building ground and found it has zero Ohms of
resistance.
Your question involves the use of building steel in a high-rise reinforced concrete construction
as a grounding electrode meeting the requirements of Section 250.52 of the NEC. Paragraph (2) of
this section recognizes the structural steel of a building as meeting the requirements as a grounding
electrode and grounding electrode conductor. Paragraph (3) describes a concrete encased electrode
and requires that the electrode itself is 20 feet of 1/2 inch or larger diameter reinforcing steel
embedded in the concrete near the bottom of the foundation or footing. The correct application in
your case is Paragraph (3) with a concrete encased electrode that is comprised of the reinforcing
steel of the poured concrete building. You indicated that others (previous installers of electrical
systems) have used the building steel as an electrode. You measured the resistance of the building
steel and found that it is zero ohms from the penthouse to the main building grounding electrode in
the basement. You indicated that the structural steel in the penthouse is bonded to the building
reinforcing steel and comprises a grounding electrode system. In effect you are dealing with a
concrete encased electrode that spans the height of the building. You ask if the department will
accept this as a grounding electrode for the building. The answer is yes, concrete encased electrodes
are recognized by the NEC and are actually a grounding electrode system that is reliable to the point
that a supplemental electrode is not required.
2. When a panelboard is fed from the secondary of a 3-phase transformer, is the panelboard
required to have a main breaker installed in it?
Yes / No. Panel boards supplied from a transformer, as permitted in 240.21(C), must have
overcurrent protection for the panelboard on the secondary side of the transformer. The
required overcurrent protection can be in a separate enclosure ahead of the panelboard, or it
can be in the panelboard [408.36, 408.36 (B)Ex. 1].
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3. I do electrical upfits in hospitals and high rises. The inspector on one of my jobs turned
me down for not having permanent placards on my panels and transformer secondary mains.
Am I required to have permanent placards or can I just label them with a permanent
marker?
First one must consider the owners wishes for what they would like to see in the way of
placarding. After that the rule of thumb is that if permanent marker is used in an indoor dry
location and is legible and properly worded then it’s okay. Permanent marker is not acceptable
where exposed and in an outdoor wet location
4. Does a receptacle installed behind a refrigerator in a single family dwelling kitchen, have
to be GFCI protected?
No
5. Can NM cable be run into a wire mold type box without being secured (fastened) to the
box?
Maybe. There is a fitting that is designed/listed to fasten NM to a metal wire mold box.
However, if a proper grommet/bushing is install to protect the NM as it enters the box and the
conductor is properly secured it can be approved without fastening to the box. Plastic boxes
that do not threaten physical damage to NM conductors may also be used without fastening to
the box.
6. When does the derating Table 310.15(B)(2)(a) apply to feeders originating in a 4000A,
480V, 3-phase 4-wire switchboard in a large commercial installation. Section
310(15)(B)(4)(a) says the neutral isn't counted if it only carries the unbalanced loads, so
derating is not necessary. However, section 310(15)(B)(4)(c) considers the neutral a current
carrying conductor when the majority of the load is non-linear. How is this calculated?
Electronic equipment, electric discharge lighting, and adjustable speed drive systems are
nonlinear loads. Nonlinear loads are defined as loads where the wave shape of the steadystate current does not follow the wave shape of the applied voltage. Nonlinear loads are a
major cause of harmonic currents and result in heating of the neutral conductor. This is
calculated as a fully loaded neutral and adds to on conduit for derating as a current carrying
conductor.
7. The way I read 314.17(C) Exception, when using a single gang non-metallic box, you need
to support the NM cable within 8 inches from the box if there's no cable connector at the
box. Most of the boxes that I use have the plastic tabs inside the box that are pressed down
when inserting the cable. For the purposes of the NEC, is this considered a cable connector?
If this tab is accidentally broken off, then does it fall under this exception? If so, then when
you break a tab off a double gang box or larger you either need to replace the box or provide
a connecting means at the box.
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Yes, the tab is an acceptable means of securing the cable to a box. The tab isn't required
where the exception is being used only for a single gang box. If the tab is broken off on two
(or more) gang boxes, then you must securing the cable to the box in some other way to
comply with 314.17(C) as all permitted wiring methods have to be secured to the box. The
broken clamp then may violate the listing of the box, and the box would need to be replaced.
See also UL White Book under QCMZ.
8. I'm an electrical inspector in a large chemical plant. During a routine safety audit in one of
the company office buildings, a 120/208-volt lighting distribution panel was inspected. Upon
opening the hinged door, we discovered that several of the 20-amp single-pole breakers had
been locked in the "ON" position, using a device which physically prevents the breaker from
being switched OFF. The circuits feed a communications hub for the building, so it is
understandable that the breakers shouldn't be turned off. However, we feel that this creates
an unsafe condition in that they could not be de-energized quickly in case of a fire or other
emergency. Is this a Code or safety violation? And would the breaker trip if it became
overloaded?
The use of breaker locks is not a Code violation. The breaker lock won't prevent
the circuit breaker from opening internally and de-energizing the circuit. Molded case circuit
breakers use a "trip free" design, meaning that the relay inside the breaker reacts
automatically to the thermal-magnetic conditions that cause a trip, even if the operating
handle is locked in the ON position.
9. Is a disconnect required at a detached residential garage or can I use the circuit breakers
located in the panel in the house? I plan to run hot, neutral and 2 travelers in a PVC conduit.
The travelers are for an outside light at the garage door entrance. The hot will feed the 3way at the house and at the garage will feed the single pole switch for the interior garage
light, a receptacle and the garage door opener receptacle.
Yes. NEC 225.31 & 225.32 & also 225.30. 225.31 requires a disconnecting
means be provided for disconnecting all ungrounded conductors that supply
another structure on the same property and that is under single management. NEC 225.32
permits the disconnecting means to be installed either inside or outside the building and
requires that it be at a readily accessible location nearest the point of entrance of the
conductors. Your proposed installation does not incorporate a disconnecting means in
accordance with 225.32. The only way to disconnect the circuit you are feeding the garage
with is at the house panel. You must install a disconnecting means such as a snap switch at
the garage to open the circuit you are using to feed the garage. Per 225.30 you must supply
the three way circuit from the detached garage’s portion of the circuit as you may not have
more than one branch circuit in the garage unless it is part of a multiwire circuit as defined
in 210.4.
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10. If you connect the grounding electrode conductor to the street side of the water meter is
it necessary to bond around the water meter?
Yes, 250.53(D). It is always necessary to bond around the water meter. If
the grounding electrode conductor is connected to the street side of the water meter and the
meter is removed you will lose the bonding connection to the interior water piping. NEC
Section 250.53(D)(1) states - the bonding connection to interior piping shall not rely on water
meters.
11. I know we must isolate the neutral conductor from the ground in a sub-panel but since
they are both connected together at the main panel anyway I don’t understand why. Could
you clarify this?
If the neutral bar in any panel other than the main service panel is bonded to the panel
enclosure this establishes a parallel path between the grounded (neutral) conductor and the
grounding (equipment-grounding) conductor. This would result in some of the neutral current
flowing in the equipment-grounding conductor and any electrically conductive material it is
connected to. The equipment-grounding conductor may be a grounding conductor run in a
cable with the circuit conductors or it may be a metal raceway enclosing the circuit
conductors. Yes, the grounded (neutral) conductor and the equipment-grounding conductors
are connected together at the main service panel or system panel where the neutral bar and
the ground bar are connected together and bonded to the panel enclosure. This connection
establishes the ground-fault path required by 250.4(A)(3, 4 & 5). This ground-fault path
creates a circuit for the ground-fault current to return to the supply source and open the
overcurrent protective device. Fault current will flow on all available paths. If parallel paths
exist the fault current may not be enough to clear the overcurrent device.
PEOPLE ● PRIDE ● PROGRESS ● PARTNERSHIPS
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Land Use and Environmental Services Agency
APRIL, MAY, JUNE
2011
MECHANICAL
PLUMBING
SECOND QUARTER 2011
NC Plumbing Code 2011
Attention:  Denotes a new question from the previous month!
 Denotes a revised/revisited question.
June 2011
Table of Contents
Chapter 1 Administration
Chapter 3 General Regulations
Chapter 5 Water Heaters
Chapter 7 Sanitary Drainage
Chapter 9 Vents
Chapter 11 Storm Drainage
POLICY
Chapter 2 Definitions
Chapter 4 Fixtures, Fau & Fit.
Chapter 6 Water Supply & Dist.
Chapter 8 Ind./Special Waste
Chapter 10 Traps, Inter. & Sep.
APPENDIX A-H
OTHER
Chapter 3 General Regulations:
1) (Q) Is a check valve required on the water supply to a mobile home?
(A) No. Water supply piping shall be directly connected to the mobile home. The utility
requirements are the same as any single family dwelling in Mecklenburg County. Ref:
301.3, 301.4 & North Carolina Mobile Home Code requirements.
2) (Q) Under what circumstances can a nylon zip tie be used as a pipe strap for pex pipe?
(A) This application can be used in parallel water distribution systems for bundling or
securing, not supporting purposes, unless the zip tie is listed for that application. Ref:
308.9
3) (Q) What is the minimum height required by code on a partition between water closets in a
multi fixture bathroom group?
(A) The code does not specifically cover the height of the partition. It requires the water
closets to be “suitably screened for privacy”. The typical partition sold is 5feet high and
there is a 1 foot clearance under partitions for cleaning and sanitation. The total height
of the partition with clearance is 6 feet. Ref: 310.4, 310.5
4) (Q) A large fast food chain wants to stay in operation during a major remodel by keeping the
drive through window open and employee’s only working in the building. The
building will not be serving customers inside the restaurant. The contractor wants to
remodel both bathrooms at the same time and provide a temporary bathroom facility
outside the building. Will this be allowed by the Plumbing Official?
(A) No. Any time you have permanent utilities on the site they must connect to the plumbing
facilities if the public or employees are still running a business out of the building.
Alternate approved method: Install a temporary handicap facility with permanent
connections to the utility for water and sanitary sewer. The walkway from the
occupied business to the bathrooms shall be covered or in a corridor and not more
that 500 feet from the employee work area. The bathroom(s) shall be handicap
accessible. Ref: 301.3, 301.4
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5) (Q) Is it required to insulate thermal expansion tanks that are installed in residential
garages? After all, there is very little if any water that would occupy space in the tank.
Should any freezing occur, there would be ample room for any expansion within the
tank.
(A) The ruling from this department on insulating appliances in a garage has been; if the
water piping must be insulated, then the expansion tank does as well. NCDOI has
concurred with this interpretation and they state “if exposed inside an unheated
residential garage, it must be insulated” Ref: 305.6
Chapter 4 Fixtures, Faucets and Fixture Fittings:
1) (Q) What is the maximum height of the curb on a shower pan threshold?
(A) There is not a maximum height for a non-handicap shower threshold. The requirement
is; “the remaining side (threshold) shall wrap over the curb”. Ref: 417.4The maximum
height for the threshold of a handicap shower, (either roll-in or transfer type) is ½ inch.
The exception is for existing facilities where structural reinforcement would be
disturbed. If that is the case a maximum threshold of 2 inches would be allowed. Ref:
ICC/ANSI A117.1- 2003
2) (Q) Can standard drywall coverings be used on the walls of a shower enclosure with shower
head?
(A) No. The wall area shall be constructed of smooth, non-corrosive, non-absorbent, and
water proof materials to a height of 6 feet. Ref: 417.4.1
3) (Q) I have an old existing apartment building three stories high that have no washer and dryer
facilities. I can alter the plumbing piping to provide a 2 inch drain for the washers. I have
no practical way to install a horizontal 3inch drain for the washers. Will the re-hab code
offer me any relief so these washers may be installed?
(A) No. The Re-hab code offers the designer no relief from the horizontal 3 Inch drain
requirement, however, the plumbing official may look at the existing DWV system to
determine the feasibility of accommodating the washers before making a final
determination. Ref: 406.3
4) (Q) Is a drain required for an outside shower used on a pool deck that hasonly a cold water
connection?
(A) No. The shower is not used for bathing and has no hot waterconnection. The water could
be considered clear water waste under normal circumstances and can drain into the
same system that is used for the pool deck drainage. Similar in some respects to
Emergency Showers and Eyewash Stations. Ref: 411
5) Q) Are bottle trap installations allowed by the NC Plumbing Code?
(A) Since they are not expressly prohibited by ICC we would have to approve them as long
as they meet the standards listed under NC IPC 421.1.2 and comply with ASME
A112.18.2. also, ref: 1002.3 #6
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6) (Q) An engineer submits a plan with a system of trench drains in a factory that drain various
grease producing cooking equipment to a grease interceptor located outside the building.
The engineer wants to pour concrete forms and install stainless steel trench drain inserts
in the concrete. The project is turned down by the plan examiner. Neither the plans nor
specifications show how the project meets 412.1 construction requirements (ASME
A112.6.3.). What information does the plan reviewer need to approve the review?
(A) The Engineer suggested supplying a letter showing how the installation met the trench
drain provision ASME A112.6.3. The CA agreed to review the engineers sealed letter.
If the letter was disapproved by the CA the engineer would be required to provide
trench drains that meet the code or have the trench drains field verified by a third
party testing agency to meet the ASTM standard. Ref: 412.1.
7) (Q) My church has ball fields and they would like to build toilets facilities in lieu of the
portable units they have now. Because they are not required by code do we have to
meet a certain number of toilets?
(A) The following code interpretation was put out by the department in 1993 with the
assistance of the parks department and should be used as a guide to determine the
fixture count for your church ball field. Ref: Table 403.1, Park Fixture Requirements.
Revised April 2009. The information on calculating the minimum facilities is in the
chapter 4 interpretations reference guide on our web site.
Chapter 5 Water Heaters:
1) (Q) May a plastic safety pan be used for a gas fired instantaneous W/H?
(A) Yes, provided that the water heaters minimum distance from combustible material is
maintained. Ref: Manufacturers Instructions
2) (Q) What is the minimum size of a water heater pan drain per the current North Carolina
Plumbing Code?
(A) The plumbing code minimum in 504.7.1 requires a ¾ inch drain minimumThis is
incorrect and is a misprint in the code. The correct minimum size is 1 Inch. See DOI
letter From Henry Webster Chief Plumbing Engineer for the State Department of
Insurance Office of the State Fire Marshall.
3) (Q) What is the maximum temperature setting for a tankless water heater allowed for a
residential use only? What if temperature exceeds 140 degrees can the water heater still be
installed?
(A) 501.6 Maximum temperature is 140 degrees. 501.8 Where temperatures exceed 140
degrees a mixing valve shall be installed.
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June 2011
4) (Q) A plumbing contractor “converted” a water heater from a 12 kW to an 18kW. The water
heater is located in the ceiling. It will be difficult for the inspector to observe the data plate
of the water heater. The new data plate reflecting the 18KW change has been added to
reflect the new heating capacity. The water heater now has dual (two) data plates. Is there
a problem with this installation change?
(A) Yes. Not allowed. The addition of a new data plate to the appliance negates the factory
listing/labeling of the appliance. The labels should be installed at the factory. From our
limited knowledge of this situation it sounds like a data plate has been taken from one
heater and added to another. Ref: Labeled by the Manufacturer, see def. 501.9
Chapter 6 Water Supply & Distribution:
1) (Q) What is the maximum distance a fixture supply pipe may be from the fixture it serves?
(A) Section 604.5 states 72”.
2) (Q) When are water hammer arrestors required?
(A) The flow velocity of the water distribution system shall be controlled to reduce the
possibility of water hammer. A water-hammer arrestor shall be installed where quickclosing valves (clothes washers and dishwashers) and metallic piping is used. The waterhammer arrestor shall not be required on any valves where plastic piping is used for
water distribution. Water-hammer arrestors shall be installed in accordance with the
manufacturer’s specifications. Water-hammer arrestors shall conform to ASSE 1010.
Ref: 604.9
3) (Q) Does the Code require a water distribution system to be sanitized?
(A) (No) 602.3.4 purged and disinfected, 610.1 purged of deleterious matter.
4) (Q) Is an expansion device required on a tankless water heater?
(A) No. An expansion device is required only if there is a tank type waterheater installed in
the residence. An expansion device is not required if hot water distribution is from a
tankless water heater. Ref: 607.3
5) (Q) The Plumbing Code defines the "Water Supply System" and gives the point where the
Water service pipe terminates and becomes the water distribution pipe. When the water is
supplied by a well and not a meter what is the starting point of the service pipe inspection?
(A) The plumbing inspections begin at the valve at the outlet of the pressure tank. Ref:
602.3.5, 602.3.5.1
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June 2011
6) (Q) When and where are pressure-reducing valves required by code, and upon what
circumstances should the Inspectors be requiring them to be installed?
(A) When the incoming water pressure exceeds 80 PSI, and on the cold water line no further
downstream than the beginning of the water distribution system. Ref: 604.8
7) (Q) Past policies have required a expansion device installed on a closed water distribution
system where there is a tank style water heater and/or backflow prevention- is this still the
case?
(A) Yes Ref: 604.8.1, 504.4.1
8) Q) How should expansion tanks be supported?
(A) Per the tank manufacturers installation instructions. Ref: 607.3.2
9)  (Q) Does the code allow a yard hydrant with a stop and waste that is fed from underground,
potable water, yard irrigation loop? The irrigation system is for a garden and not close
to any structure
(A) No. The code does not allow a stop and waste on a potable water system. Any
underground opening represents a possibility of contamination through back siphon
age into the potable water system. Alternate approved method. A stop-and–waste
may be installed in the situation noted above if a reduced pressure backflow
preventer on the potable irrigation loop is installed and the piping is identified from
the RP to the yard hydrant as non-potable water. Non -potable piping must be
painted yellow with black lettering stating “NON POTABLE WATER”. Ref: 608.7,
608.8.2
Chapter 7 Sanitary Drainage:
(1) (Q). Can a force main tie into gravity drain line? If yes can a Y connection be used for
this purpose? What other requirements apply to meet code minimums?
(A) Yes. Must be 10 feet from the base of any soil stack, waste stack, or fixture drain
or the connection to a septic tank. Where the connection is to a horizontal drain
pipe the ejector shall be made on top of the drain pipe through a wye fitting at an
angle of 45 deg. Ref: 712.3.5
2) (Q) A plumbing contractor wants to use saddle valves to tap a live 6 inch main. The approval is
based on an engineer approved letter of approval for use of the valve as an alternate
method. Is this allowed?
(A) No. Saddle valves are clearly prohibited by the code. Ref: 707.1 #6
3) (Q) Is the flexible drain line piping approved for under sink waste piping?
(A) No. Flexible drain piping, sold at most of the big box stores, is not approved by the NC
Plumbing Code. The fittings shall not have ledges, shoulders or reductions capable of
retarding or obstructing flow in the piping. Threaded drainage pipe fittings shall be of
the recessed drainage type. Ref: 706.2
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June 2011
Chapter 8 Indirect/Special Waste:
1) (Q) What is a sacristy and what special allowances apply?
(A) It is one use where the drain is allowed to discharge directly into a drywell outside of the
structure. Ref: 803.4
2) (Q) Can the tail piece of a lavatory or sink be used as a direct connection for the drainage from
an ice maker or medical equipment?
(A) No. An air gap shall be provided and the waste shall discharge into an approved
receptor to protect against backflow. Ref: Section 801.2, 802.1, and 802.1.6
3) (Q) Do all acid waste neutralization tanks require a monitoring device with alarm?
(A) Yes. We require monitoring and alarms on all neutralization tanks installed in
Mecklenburg County. Ref: Code Interpretation Letter & 702.5/803.2,803.5.
4) (Q) Can the discharge from a three compartment sink in a commercial Restaurant be pumped to
an indirect waste receptor in a remote location?
(A) Yes. The three compartment sink shall discharge through a flow control fitting and a
point of use grease interceptor before terminating in the lift station. The lift station
pumped discharge shall have a check valve and terminate over an indirect waste
receptor which must be visible from the three compartment sink location. Ref: 802.1.1,
802.2.1
5) (Q) Is a condensate pump that is not listed for installation in a plenum allowed in a plenum if it
has all non –combustible parts?
(A) Yes. (307.2.1, 307.2.2 Mech. Code) The plumbing official may allow the use of this pump
as an equivalency to a listed pump under the conditions stated above. Ref: 801.1
Chapter 10 Traps, Interceptors & Seperators:
1) (Q) What is required for laundry drain protection for lint, buttons or strings?
(A) Laundries other than a single family residence, shall be equipped with a manufactured
device (not field fabricated) that will limit lint, buttons or string larger than ½” from
entering the drainage system. Ref: 1003.6
2) (Q) Is a separate draw off storage tank allowed to be installed as part of an oil/water separator
installation?
(A) Yes. When circumstances exist on a site that would not permit the full storage tank
capacity calculated for an integral storage oil/water separator to be installed, an integral
separator sized to meet the minimum capacity of the code may be installed with an
additional draw off tank to store the remaining capacity calculated for the separator. All
other requirements for oil/water separators installed in Mecklenburg County shall
remain the same. Ref: 1003.1, 1003.2, 1003.4, & 1003.4.2
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3)
June 2011
(Q) Grease interceptors that are required by the plumbing code and by Charlotte
Mecklenburg Utility Department should be designed to meet both standards. The
utility company would like Mecklenburg County to alter its policy statement. Is
there any reason we should not honor that request?
(A) No. Unless the change is a violation of current code we can honor their
request. They would like us to add the access provision to our requirements.
This standard provision would require access to each chamber separately of a
grease interceptor. Out policy will be revised to reflect this change. Ref:
1003.3
4)
(Q) The plumbing plans examiner has turned down a plan requiring a system of floor drains
or trench drains in a repair garage that will have to discharge through an oil/water
separator. The owner calls the CA to find out if he may use dry clean up and
environmental disposal of waste just like the garage next door to his has for years?
(A) If the owner does not have floor drains or trench drains and uses dry clean up and
proper environmental disposal methods per our on line OWS interpretation, I see no
reason to require the OWS. I would always advise checking the plans to get the
overall picture of the project. We may not be getting the whole picture. If there are
existing floors or trench drains in the original building they are adding on to then the
new floor and trench drains should be added to the original drain installation and the
OWS sized to accommodate all the waste from the garage floor. We need to get a
letter from the owner about the pick up and disposal of the dry clean up material
Ref: Oil Water Separator Policy letter on our web site. Exception to 1003.4
Chapter 11 Storm Drainage:
1) (Q) How do vertical walls affect roof drain calculations?
(A) In sizing roof drains and storm drainage piping, one-half of the area of any
vertical wall that diverts rainwater to the roof shall be added to the projected
roof area for inclusion in calculating the required size of vertical conductors,
leaders and horizontal storm drainage piping. Ref: 1106.4
2) (Q) I am attaching a handmade metal box I designed to a 4 inch overflow roof drain that
terminates on the side wall of an apartment building. I am installing a screen in the box to
restrict the flow so the water will not be pouring down the side of the building and staining
the brick finish. Does this installation meet the Code?
(A) No. The size of the drainage pipe is reduced in the direction of flow. The fitting is not
approved and retards the direction of flow. The fitting has shoulders and/or reductions
that retard flow. Strainers are allowed on roof surfaces only for overflow drains this is a
side wall mounted fitting. Ref: 1101.5, 1101.6, 1102.7, 1105.1, 1107.2
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June 2011
3)  (Q) Is it still applicable to use the 3.2” and 6.6” rainfall amounts for primary and secondary
roof drain quantities? These values were in the table approved by Phil Edwards for
rainfall as long as we noted on the plans that we used those totals? It has been about 8-12
months since I last checked.
(A) Yes. You can still use either the NC Plumbing Code calculations or CMUD data. It is
the designers’ choice as long as the code tables do not contain a lesser value than local
weather conditions. The rainfall amounts in your email are from CMUD data and
would still apply for local rainfall amounts used in your calculations. Ref: 1106.1
POLICY:
1) (Q) What is the maximum depth that a two-way C/O may be installed?
(A) The maximum depth shall not exceed 24” below grade. If deeper depths are required,
then an additional combination may be placed as close as possible downstream of the
required building drain/sewer junction C/O.
2) (Q) A single family home is connected to a septic tank. Can a dishwasher or washing machine
be connected to the drainage system of the house? Can the washing machine be connected
to a dry well?
(A) The homeowner would be required to contact the Environmental Health Department for
Mecklenburg County. They regulate the installation, repair, and alteration of the septic
tank systems in Mecklenburg County.
3) (Q) I’ve received a complaint on one of our child care centers and apparently the center’s
sewage grinder tank does not work properly, to the point that the center has their tank
pumped weekly or whenever the tank’s alarm goes off. The tank overflows into the
adjacent playground/parking lot. I’m planning to visit the facility and advise them that
the sewage cannot flow onto the ground and that their sewage system must work
properly. That being said, the caller also advised that the grinder in the tank was not
adequate when it was installed. As far as the effectiveness of the grinder tank, will the
issue fall under Code Enforcement?
(A) We do not get involved with the performance of the pump; it comes down to “Does the
pump/tank operate as designed?” It goes back to the installing contractor- he/she is
liable for the design/installation/performance of the equipment. If I were the tenant, I
would call the installing contractor and have them check on why it did not work as
designed.
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June 2011
9
4rth
3rd
2nd
1st
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above
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NC Fuel Gas Code 2011
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June 2011
Table of Contents
Chapter 1 Administration
Chapter 3 General Regulations
Chapter 5 Chimneys & Vents
Chapter 7 Gaseous Hydrogen S.
POLICY
Chapter 2 Definitions
Chapter 4 Gas Piping Install.
Chapter 6 Specific Appliances.
Chapter 8 Ind./Special Waste
OTHER
Chapter 3General Regulations:
1) (Q) The installation instructions for an 80 percent furnace cautions against
providing combustion air from areas such as laundry rooms. The
manufacturer states that installation of a furnace adjacent to laundry
equipment can lead to premature corrosion from chemicals in laundry
detergents. Would it be acceptable to draw combustion air from an open
basement or garage, which by definition is not a confined space, even though
laundry equipment is also located in that space?
A) The unit must be installed according to manufacturer's specifications;
however, as long as it is not in a confined space and the area can provide
adequate combustion air, the installation described above would not be an
issue. The intent of the manufacturers' caution statement is to address a
small room specifically designated as a laundry room. 303.1 (FGC)
Chapter 4 Gas Piping Installation:
1)
(Q) When and where are sediment traps required?
A) Section 408 requires a sediment trap as close as practical to the inlet side
of the equipment. This would include gas regulators. Regulators for
individual appliances may utilize a single trap for both the regulator as
well as the appliance. Illuminating appliances, ranges, clothes dryers, gas
logs, log lighters and outdoor grills are exempt from traps. Ref: 408
(FGC)
2)
(Q) May a flexible gas connector run through the appliance housing?
A) No! Ref: 411.1.3.3 (FGC)
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Chapter 5 Chimneys and Vents:
1) (Q) I am terminating a direct vent appliance on the exterior wall of a residential
building. The fireplace I am venting is on the same wall as the porch. The
porch is open on three sides and the termination cap provides adequate
protection for the vent opening. Am I allowed to install this per code?
A) Yes. A venting system shall be designed and constructed so as to develop a
positive flow adequate to convey flue or vent gases to the outdoor
atmosphere. Once a deck is completely covered and/or screened in, it now
could be an occupied space and would no longer be considered outdoors. We
have to depend on the field Inspector to make an informed judgment. There
are special circumstances where this would be allowed. If the manufacturer’s
instructions allow the installation on an open porch (3 sides)and the
termination vent is protected the installation may be allowed. Ref: 503.3
2) (Q) Screws in venting: Are they necessary? For example, in type B venting.
A) No. Some Manufacturer’s instructions actually allow screws at joints as long as 3
they do not penetrate past the outer wall of the B vent. Ref: 503.6
Chapter 6 Specific Appliances :
1) (Q) I want to install code approved unvented gas logs in a commercial restaurant
that seats 100 people. Can this appliance be installed in an assembly
occupancy?
A) No. Unvented room heaters shall not be installed within Groups A, E, and I
Occupancies. Ref: 621.4 (FGC)
2) (Q) A new 5 million BTUH instantaneous water heater is being installed in an
existing food processing plant. The water heater is located in an existing pump
room that also contains electrical panels. The pump room area is 1000 square
feet. Combustion and ventilation air openings are installed high and low and
meet code sizing requirements. Does the pump room have to comply with the
boiler room requirements of [B] 1015.3 for egress?
A) Yes. At 15.1 Boiler Horse Power it will require two remote exit doors per the
Building Code.
3) (Q) What is the BTUH conversion factor for BTUH to Boiler Horse Power?
A) One boiler horse power equal 330,000 BTUH.
4) (Q) Are there other factors or trade requirements that may be effected by the
installation of the boiler in the pump room?
A) Inspectors should be aware of clearance to combustibles. Ref: 631.3. (FGC)
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Table of Contents
Chapter 1 Administration
Chapter 2 Definitions
Chapter 3 General Regulations
Chapter 4 Ventilation.
Chapter 5 Exhaust Systems
Chapter 6 Duct Systems
Chapter 7 Combustion Air
Chapter 8 Chimneys & Vents
Chapter 9 Specific Appliances
Chapter 10 Boilers, Water Htrs
Chapter 11 Refrigeration
Chapter 12 Hydronic Piping
Chapter 13 Fuel Oil Piping
Chapter 14 Solar Systems
POLICY
OTHER
Chapter 1 Administration:
(A) (Q) Is it the responsibility of a plans examiner or inspector to inform a designer or contractor
of additional requirements of other State agencies or licensing boards?
(B) No. It is not the responsibility of the inspector or plans examiner. It shall be the
responsibility of the permit holder, design professional, contractor, or occupational license
holder to determine whether any additional requirements exist. 101.5
Chapter 3 General Requirements:
1) (Q) What are the requirements for systems installed in a flood plain?
(A) Section 301.13 Flood hazard: For structures located in flood hazard areas, mechanical
systems, equipment and appliances shall be located at or above the design flood
elevation. Exception: Mechanical systems, equipment and appliances are permittedto
be located below the design flood elevation provided that they are designed andinstalled
to prevent water from entering or accumulating within the components and to resist
hydrostatic and hydrodynamic loads and stresses, including theeffects of buoyancy,
during the occurrence of flooding to the design flood elevationin compliance with the
flood-resistant construction requirements of the International Building Code.301.13.1
High-velocity wave action. In flood hazard areas subject to high-velocity wave action,
mechanical systems and equipment shall not be mounted on or penetrate walls intended
to break away under flood loads. See also section 602.4 for similar the requirements
covering the duct system.
2) (Q) Would the discharge line of an appliance condensate pump need to be protected from
freezing temperatures?
(A) Chapter 307 does not address the protection of condensate discharge lines, installed in
areas subject to freezing temperatures, however, we would be remiss if we did not
require this protection in areas such as a ventilated attic space. Other areas of concern
would be where the line exits the foundation wall. We would “recommend” that these
installations be sloped downward and increasing in pipe size to limit blockages.
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3) (Q) What type of access would be required for a boiler installation where the boiler devices
may be subject to vandalism or component theft?
(A) Chapter 306 covers the typical installation of equipment. Section 105.1 Would allow us
the flexibility to allow alternative access on a case by case basis.
4) Q) Where are the seismic strapping requirements for air conditioners and/or heat
pumps in the NC Mechanical Code?
(A) Seismic requirements and zone information is in the Building Code as
referenced by 301.15 of the Mechanical Code.
5) (Q Do copper condensate lines or return piping of heating/cooling units that are in direct
contact with galvanized sheet metal duct and/or plenum constitute a potential for galvanic
action?
(A) It is recommended that piping be protected from potential corrosion by protecting or
isolating the piping. 307.2.2
6)  (Q) What is the proper way to protect an appliance in a residential garage?
(A) From the information we have from DOI and past practice if you pulled a straight
edge from the garage door opening to the rear of the opening, if the appliance in
question was not in the normal path of the vehicle, then no protection is required.
No what if’s Ref: 303.4
7)  (Q) A mechanical contractor requested an interpretation as to whether traps were required
on the condensate from an evaporator coil and if we knew of any conflicts with the
energy code involving cleanout vent/ tees on a blow-through unit discharging into an
unconditioned area (attic/crawl space)?
(A) The code requires the inspector to rely on the manufacturer’s data to determine if a
trapped drain is required. If any conflicts with other codes are apparent then the
contractor may need to consult with the manufacturer to resolve the problem and
inform the inspector of the issues. Ref: 307.2.4
Chapter 4 Ventilation:
1) (Q) What is the minimum ventilation required for toilet rooms?
(A) Toilet rooms are not considered to be habitable space and so their
ventilation requirements would be found in table 403.3 which would require
mechanical exhaust and not natural ventilation. Note: We have allowed natural
ventilation in the past and we will begin enforcing the mechanical ventilation
requirement on permits obtained after April 1, 2011.
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Chapter 5 Exhaust Systems:
1) (Q) Does Mecklenburg County allow an alternative method for type I hood
clearances?
(A) Mecklenburg County allows the use of NFPA 96, Chapter 4.2.3.2 based
on an interpretation by DOI dated 2/2/2004.
2) (Q) In an automotive repair garage with a vehicle exhaust source capture system per NCMC
502.14, is it permitted to have one (1) –exhaust capture connection for every two (2) bays
or is one connection only allowed per bay?
(A) The Mechanical Code is silent on this question, however the code language gives the
inference that it requires a singular; “a source capture system” for each vehicle or
service bay. One per bay is required. Ref: 502.14
3) (Q) Even though the code requirements have been met for the installation of the grease duct
the contractor wants to add several more cleanout openings because he also has the
maintenance contract on the grease duct system. The duct is only 10 inches by 10 inches
and the code access door manufacturer informs him the smallest door approved for
grease duct installation per code is 12 inches by 12 inches. Can the contractor make his
own door to access the grease duct?
(A) Yes. Where the duct is smaller than the 12 by 12 minimum the mechanical contractor
may provide cleanouts approved by the mechanical official at least equivalent to the
minimum requirements of the code for manufactured access doors. Ref: 506.3.9
4) (Q)The Mechanical inspector has turned a residential range exhaust installation down
because the contractor has used screws to join the pipe together and then sealed the pipe
joints with mastic. The pipe extends up through the roof and is terminated per code. Is this
inspector correct? Is this a code violation?
(A) The inspector may consider this a code violation; reference is 505.1 “smooth inner
walls,” however there are minimal code restrictions on residential hood installations.
While the code reference says smooth we would accept small screws and mastic to
fasten the duct joints together. Ref: 505.1
5) (Q) A contractor asks the inspector if he can combine the bathroom exhaust with the dryer
exhaust to value engineer the job for the owner and appease the Architect who is
complaining about all of the exterior wall penetrations disturbing the ambiance of his
finished exterior walls. Can the inspector allow this installation? Will a redesign in duct
sizing, fittings or joints be required?
(A) No. No comingling of the dryer exhaust is allowed by code. Ref: 504.1
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6) (Q) A battery room is installed in an existing multistory building. The designer says it is
virtually impossible to run the exhaust duct up to the roof because of the tenants and
space in the ceiling above so he wants to run the duct into an area way in the middle of
the building that is enclosed on all four sides similar to an interior courtyard in an office
building. The only thing located in the area way are 10 compressors for AC to the
various building tenants. His problem with running the duct to the area way is that he can
only get 3 feet of clearance to terminate the exhaust duct. Can this installation be allowed
per Code?
(A) No, Ref: 501.2.1 sub (1) for conveyance of flammable/explosive vapors.
7) (Q) A UL listed grease duct installation for a type I hood is called for inspection. Duct joints
are not welded per code requirements; however, the installation instructions show
approved joint connections without welded joints. What would the inspector be required
to inspect? How does the inspector look at the installation for code compliance? What
tests are required for system approval?
(A) Inspection of the manufactured system would have to comply with all standard tests
for grease duct required for type I hoods including 506.3.2.5. Any tests specified in the
manufacturers literature will also be the responsibility of the field inspector. Ref:
506.3.2.5
8) (Q) Under what conditions can an outdoor grill and hood be installed under a covered porch?
(A) The hood would be approved if installed per the manufacturer’s installation
instructions, including the correct fan, and unit sizing-and it is used in a single family
detached dwelling. No townhouse/condo/apartment use would be allowed. Ref: 506.4.1
9) (Q) A manufacturer has submitted a dryer booster fan to be used in a residential application
per IRC 1501. Would the inspector approve the booster fan if the contractor has the
letter on site for the inspection?
(A) Dryer booster fans are not allowed by the code. There is no code language to allow
their use. Ref: 504.1
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Chapter 6 Duct Systems:
1) (Q) What method can be used to protect the opening in a floor/ceiling or roof/ceiling
assembly where supply duct from the HVAC unit penetrates the assembly? NOTE: There
is not a fire damper currently manufactured that is approved for this application when the
multi-story building is classified as an R2 occupancy with type V construction.
(A) The current code approval for this application requires a smoke detector to be
installed in the same room as the HVAC unit that will shut down the unit if smoke is
detected. The smoke detector shall tie in to the smoke detector circuit provided for the
apt/condo unit. A static damper is required at the ceiling penetration of the HVAC duct
penetrations from the unit. This method of protecting the ceiling penetrations is only
approved until a Fire Damper is manufactured that provides adequate protection for
the openings.
2) (Q) What are the minimum requirements for plenum rated materials within an open air
plenum space?
(A) Not required. See plenum definition. Open air returns are typically in habitable areas
and do not have to conform to the material requirements of enclosed plenums.
Example: Home Depot. Ref: Chapter 2 plenum definition. & 602.2.1
3) (Q) Unlisted duct tape has been installed on the metal to metal and flex to metal airduct joints
of a furnace installation in a single-family dwelling. Is it required that the unlisted duct
tape be removed before installing the approved tape or mastic?
(A) No, approved tape may be installed over unlisted duct tape unless the listing, labeling
or manufacturer’s instructions supersede the allowance of such material. Ref: 603.9
4) (Q) What is considered proper access for smoke/fire dampers?
(A) MC 607.5 states that the damper must be accessible for removal/maintenance.
5) (Q) Are fire dampers, smoke dampers, or combination dampers required in walls that
separate a garage from the residential living space in a single family dwelling?
(A) The code has no provisions for a fire damper of any type to be required in this
residential installation. 603.1.2
6) (Q) Are longitudinal seams required to be sealed in a duct used to exhaust a bath fan?
(A) Yes. Our policy has always been to seal the seams in a longitudinal duct run in a
residential application to prevent any duct leakage on the ceiling. Recent DOI
interpretations of the 2012 code MC Section 603.9 back the department position to
seal the exhaust duct. The 2009 code vaguely describes “contamination prevention”
in 601.4 but exempts one and two family dwellings. Ref; 603.9
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7) (Q) A listed and labeled product (return air grill) is being installed in a panned 2 by 4 wall
stud cavity. A return air grill is being installed in the wall cavity at a depth of 1 inch
leaving only 2 inches between the return collar and the filter. Is this installation allowed
by Code?
(A) The inspector must look at the surface area to determine if this installation will meet
code. Ref: 602.3, 605.2
8) (Q) Charlotte Pipe has a new CPVC pipe called ChemDrain with a Zero flame spread rating
and a smoke developed rating of between 8 and 22 based on ULC S102.2. Can we allow
this new pipe in return air plenums?
(A) Yes. As long as it is tested and approved for at least 25-50 smoke and flame spread
rating we would allow the product in return air plenums. Ref: 602.2.1
Chapter 9 Specific Appliances, Fireplaces and Solid Fuel-Burning Equipment:
1) (Q) What is the minimum clearance of a microwave oven hung under an existing stove cook
top? The manufacturer’s instructions require a 24 inch clearance. This clearance will work
but just barely because of the existing cabinet height. The house is in a historic district and
the governing board does not allow removal or alteration of existing cabinets in the district.
Can the inspector allow the manufacturers approved clearance?
(A) Yes. Install the equipment per manufacturer’s clearances. Ref: 917.4
Chapter 10 Boilers, Water Heaters and Pressure Vessels:
(1) (Q) An out of state jurisdiction ask the department about the enforcement of ASME Boiler
and Pressure vessel regulation enforcement for the state of North Carolina. Who
enforces regulations for UNFIRED pressure vessels for (1) Newly installed pressure
vessels to comply with ASME Boiler and Pressure Vessel Code, (2) Repairs and
alterations for existing boilers, and (3) Other regulations or codes that also apply to
boilers?
(A) The Department of Labor Boiler and Pressure Vessel division has primary
responsibility over boiler inspections, however there is a list of exempt boilers. The
exempt boilers are governed by the North Carolina Mechanical and Fuel Gas codes
as enforced by the Office of the State Fire Marshall through the Department of
Insurance. Ref: Ch. 10 and NCGS 95-69.10/ BPV Rules.
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Chapter 11 Refrigeration:
1) (Q) An existing chiller is being replaced. The existing chiller uses R-22. The chiller is in an
existing mechanical room. The new chiller will be using the more environmentally
friendly R-410-A refrigerant. The existing chiller room has a volume of 925 sq. feet and a
cu ft. volume of 12,025. The new chiller has 160 lb of R-410A in its largest refrigerant
circuit. The chillers quantity exceeds the capacity of the room as provided for in the chart
in tbl. 1103.1 2009 NC mech. Code. Table 1103.1 has been changed in the 2012 North
Carolina code and the quantity of R-410 has been reduced to 25lb/1000 cu. ft. There are
no other changes in the code that would change the quantities. Can the code official
allow the new code quantities to be used so a separate mechanical room will not be
required?
(A) Since there are no other changes that would require the designer to build a separate
mechanical room the new table quantity is approved as an alternate design. Ref:
Table 1103.1- 2012 and Table 1103.1- 2009
Policy: Includes Energy Conservation and Re-Hab Codes
1) (Q) When is a refrigeration permit required?
(A) A refrigeration permit is required for any refrigeration equipment required to be
assembled (excluding the walk-in cooler box) OR any equipment required to be hard
wired electrically (not cord and plug type).
2) (Q) Is the outside air make-up air duct located on the non-insulated side of an attic space in
a single family dwelling required to be insulated?
(A) No. The temperature difference between the air in the make-up air duct
and the air temperature in the attic are not sufficient to cause condensate
that would require insulating the duct. Ref: 503.2.7, Exception #2, North Carolina
Energy Conservation Code
3) (Q)When does a Mechanical Inspector enforce the Carbon Monoxide Alarm requirements
adopted by the NC Department of Insurance in One-and-Two-Family Dwellings and
Townhouses? Effective date: January 1, 2011.
(A) 2009 NC Residential Code revisions to Section R313 as provided below:
R313.1.1 Carbon Monoxide alarms. In new construction, dwelling units shall be
provided with an approved carbon monoxide alarm installed outside of each separate
sleeping area in the immediate vicinity of the bedroom(s) as directed by the alarm
manufacturer. R313.1.2 Where required-existing dwellings. In existing dwellings,
where interior alterations, repairs, fuel-fired appliance replacements, or additions
requiring a permit occur, or where one or more sleeping rooms are added or created,
carbon monoxide alarms shall be provided in accordance with Section 313.1.1.
R313.1.3 The required carbon monoxide alarms shall be audible in all bedrooms over
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background noise levels with all intervening doors closed. Single station carbon
monoxide alarms shall be listed as complying with UL 2034 and shall be installed in
accordance with this code and the manufacturer’s installation instructions.
4) (Q Can R-4 insulated Flex be used in Icynene insulated attics where a thermal barrier is
above the ductwork?
(A) Yes. It can be used as long as the attic is now part of the thermal envelope and properly
sealed. Ref: 503.2.7, NC Energy Conservation Code
5) (Q) Does the code limit the noise level produced by heat pumps and air conditioners?
(A) No. There are not any requirements restricting the noise levels of this equipment in the
current code. Local ordinances dictate noise levels and are not enforced by building
code enforcement officials in Mecklenburg County.
6) (Q) When extending gas pipe to non-electrical gas equipment (barbecue, insert, are you
required to bond the existing gas pipe connected to an existing gas or electrical appliance?
(A) No, unless the alteration creates the potential to be energized.
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