HOUSE CONSISTENCY MEETING
Date: 6-12-2013
DEPARTMENTAL GOALS:
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85 - 90 % 1 DAY TURN AROUND
80 - 85 % CONTRACTOR PASS RATE
QUALITY INSPECTIONS!
EXCELLENT CUSTOMER SERVICE!
SAFETY ISSUES:
REMEMBER COUNTY CELL PHONE POLICY, USE ALL APPROVED SAFETY
EQUIPMENT ISSUED TO YOU. (i.e. HARDHAT, SAFETY GLASSES, SAFETY SHOES,
PPE)
Q: WHY ARE WE HERE? A: TO SERVE THE CUSTOMER
1. We increased the size of the circuit conductors on a pumping station, that required 60 amp
overcurrent protection, to compensate for the voltage drop. We increased in size from a #6
AWG copper to a 1/0 copper conductor. What, if anything, needs to be done with the
equipment grounding conductor when the circuit conductors are increased? What size EGC
would be required in this case? Joe W
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250.122(B) Chapter 9, Table 8
The equipment grounding conductor shall be increased by the same proportion as the increase
in ungrounded conductor size.
6 AWG = 26,240 cm
1/0 AWG = 105,600 cm
105,600 cm/26,240 cm = 4.02 times as large
60 amp = #10 EGC = 10380 cm
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10380 x 4.02 = 41727.6
411727.6 rounds up to 41704 or a #4 EGC
What happens on the job when you see a 450 amp circuit fed by 2 parallel 500 kcmil conductors
with # 2EGC?
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Assume smallest comparable parallel conductor for breaker size.
Two 4/0 = 460 amp @ 75 deg.
4/0 = 211600 cm x 2 =423200 cm
500kcmil x 2 = 1,000,000 cm
1,000,000 cm / 423200cm = 2.36
450 amp = #2 EGC = 66360 cm
66360 x 2.36 = 156805
156805 rounds up to 3/0 EGC in each raceway
2. A transformer has the neutral bonded inside the transformer. Where is the grounding
electrode conductor to be connected, the panel or the transformer? Barnes
At the transformer per 250.30(A)(5) or 250.30(A)(6). Both of these sections require the
grounding electrode conductor connection to be made at the same point as where the system
bonding jumper is connected to the neutral (grounded) conductor.
3. Am I required to install an intersystem bonding terminal at a detached garage? King
Maybe
An intersystem bonding termination for connecting intersystem bonding conductors required for other
systems shall be provided external to enclosures at the service equipment or metering equipment
enclosure and at the disconnecting means for any additional buildings or structures. The intersystem
bonding termination shall comply with the following:
*****Exception: In existing buildings or structures where any of the intersystem bonding and
grounding electrode conductors required by 770.100(B)(2), 800.100(B)(2), 810.21(F)(2),
820.100(B)(2), and 830.100(B)(2) exist, installation of the intersystem bonding termination is not
required. An accessible means external to enclosures for connecting intersystem bonding and
grounding electrode conductors shall be permitted at the service equipment and at the disconnecting
means for any additional buildings or structures by at least one of the following means:
(1) Exposed nonflexible metallic raceways
(2) An exposed grounding electrode conductor
(3) Approved means for the external connection of a copper or other corrosion-resistant bonding or
grounding electrode conductor to the grounded raceway or equipment
4. The optional calculation has a slight variation from the dwelling unit (220.82) to the
multifamily (220.84). My question is about the calculated loads in 220.84(c); specifically
number (5), which states “the larger of the air- conditioning load or the fixed electric spaceheating load. (1) Does the air-conditioning include both the heat pump and the air handler? I
think it does, and should include the supplemental heat. In the dwelling unit section, 220.82(c)
says to add the largest of the 6 options; the common one used is 100 percent of the heat pump
plus 65 percent of the supplemental heat.
(2) In comparing 220.82 and 220.84, if we’re dealing with a single dwelling unit in a multi-family
building, which section do we apply for its calculation? West
It must first be said that it is the designer’s choice to use the standard or optional calculation
method. When the optional method is chosen you may use 220.82 to calculate feeder or
service load for a single dwelling unit of a multifamily building. 220.82 has its own set of demand
factors built in for the diversities of a single unit. 220.82(C) gives you six ways to apply demand
for the HVAC of this single unit.
For feeder or service calculations for three or more dwelling units in a multifamily building,
section 220.84 along with table 220.84 may be used. Note that in 220.84(C)(5) there is only one
way of looking at the HVAC load. Either the larger of the entire heat load or the entire a/c load,
(that means the heat pump and air handler if both run at the same time), must be added to the
other features found in 220.84(C)(1) through 220.84(C)(4). The demand factors for all the
diversities of these units is accounted for in Table 220.84, and may then be applied to that
number.
5. The interior of a space is served by unit equipment complying with 700.12 and has 2 exits.
Each of the exits have an exterior emergency light, can the exterior emergency lights be served
from the circuit that supplies the units on the inside of the space since the lights are actually
serving to illuminate the exits for the people exiting the space? West
NEC 700.12(F) Exp. 2. Remote heads providing lighting for the exterior of an exit door shall be
permitted to be supplied by the unit equipment serving the area immediately inside the exit
door.
Further discussion
The 2012 NC Building Code 1006.1 Requires Illumination for the means of egress, including the
exit discharge, shall be illuminated at all times the building space served by the means of egress
is occupied.
This is not talking about emergency power illumination. This could mean you have a remote
head outside the door tied to a emer/exit light inside , and still be required to have a non-emerg.
light outside to illuminate the exit discharge controlled by TC or PE. You could go on and on
depending upon your particular design.
6. A swimming pool installed at a single-family dwelling has several motors, as well as other
loads associated with it, and a panel in a NEMA 3R enclosure is installed on posts (pedestal)
near the pool equipment to serve these loads. An inspector is calling this a separate structure
and is requiring a main breaker in the pool panel. Are the posts that the pool panel is mounted
to considered to be a structure? Mullis
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Yes, (see documentation from Code Making Panel 1 below).
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Obviously the panelboard cannot be mounted to the swimming pool so the posts provide a
support means for the panelboard. The panelboard is supplied by an outdoor feeder, that is in
turn supplying branch circuits for equipment installed in, or associated with, the swimming pool.
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All applicable requirements from Part II of Article 225, including the disconnect requirement are
in play. Depending on the number of branch circuits and their arrangement (i.e. multiwire), it
may be possible to use the six disconnect rule in 225.33(A)&(B). The requirements of 250.32(A)
and (B) must be followed.
1-65 Log #3440 NEC-P01 Final Action: Reject
(100.Structure)
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Submitter: William Benard, Gemini Electric Inc.
Recommendation: Add new text to read as follows:
That which is built or constructed for other than listed or identified
freestanding electrical equipment.
Substantiation: This proposal attempts to address different interpretations of
the term structure especially when a disconnecting means is required at a
structure in Section 225.32 and in at least one case by clarifying that a
disconnecting means is not required at a standalone transfer switch or other
approved freestanding transfer equipment where the conductors are already
protected by equipment ahead at the source as in the case of a generator with a
built in feeder disconnect.
Although not all in the industry would consider standalone transfer
equipment as a “structure,” it is hard to convince those that do that such
equipment does not fit the existing literal wording in the definition of the term
in Article 100. The addition of the wording in the new definition would clarify
for more consistent interpretation and determination as to the intention of the
protection requirements determined for a “structure.” If freestanding electrical
equipment is intended to qualify as a “structure” then the listing evaluation
should consider construction and structural integrity as a component of the
package listing mark, and they do not at this time.
Panel Meeting Action: Reject
Panel Statement: Freestanding electrical equipment is a structure. The
problem is better addressed in the rules pertaining to it. Structural integrity of
listed products is addressed as part of the listing standard. Based on the
submitter’s substantiation, a proposal to revise the requirements of Sec. 225.32
may be more appropriate.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12
7. Where a set of branch circuit conductors only pass through a panelboard and do not
originate or terminate in the panelboard they are passing through, is there any requirement for
identifying where the overcurrent device is located for these conductors? Sloop
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Yes. Section 312.8(3) states:
A warning label is applied to the enclosure that identifies the closest disconnecting means for any
feed-through conductors.
Added to the Code in 2011, this requirement is focused on improving worker safety by facilitating
the practice of working on de-energized conductors and circuit parts.
8. There is a new product on the market that has a single yoke and contains a single receptacle
and 2 USB ports. If the device is rated 15 amps then may it be fed with an individual 20 amp
circuit? And may it be used on the kitchen counter as part of the small appliance branch circuit?
Here is the device in question. King
No to the individual branch circuit, as 210.21(B)(1) states that a single receptacle installed on an
individual branch circuit shall have an ampere rating not less than that of the branch circuit.
Yes, per 210.21(B)(3),where connected to a branch circuit supplying two or more receptacles or
outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3) would permit
the receptacle to have a 15 ampere rating.
9. A 15-ampere, 120-volt duplex rated receptacle is installed to supply a 1/3 HP, 120-volt
disposal from a 20-ampere rated circuit. A CO/ALR 120-volt, 15-ampere, general-use rated snap
switch is installed to control the disposal’s operation. Does this installation meet NEC
requirements? Miller
Yes, 210.21(B)(3) permits a 15 ampere duplex on a 20 ampere circuit.
430.109(C)(2) States that for stationary motors rated at 2 hp or less and 300 volts or less, the
disconnecting means shall be permitted to be one of the devices specified in (1), (2), or (3):
(1) A general-use switch having an ampere rating not less than twice the full-load current rating
of the motor See related UL
(2) On ac circuits, a general-use snap switch suitable only for use on ac (not general-use ac–dc
snap switches) where the motor full-load current rating is not more than 80 percent of the
ampere rating of the switch
Also see 430.109(F) and 422.33.
UL product category RTRT tells us that a 125volt, 15 amp receptacle is tested for ½ HP. Also UL
product category WJQR tells us that general use snap switches are tested for motor loads up to
80% of the amp rating of the switch, but not exceeding 2 hp.
10. Are chase nipples recognized for bonding purposes between two metallic enclosures on the
line side of the service disconnecting means? How about on the load side of the service
equipment? Joe W
A chase nipple would be considered a conduit fitting and covered by UL Product Category
DWTT. All fittings are intended to be installed in accordance with the NEC. All metal fittings for
metal cable, conduit and tubing are considered suitable for grounding for use in circuits over
and under 250 V and where installed in accordance with the NEC, except as noted for flexible
metal conduit fittings and liquid-tight flexible metal conduit fittings.
As for bonding on the line side of the service, the chase nipple would not comply with the
provisions of 250.92(B), however on the load side would comply with the provisions of 250.97.
11. Is it permitted to use the same EGC (equipment grounding conductor) for two separate
systems with two different voltages, such as a 277/480 and a 120/240 volt system? West
Yes, also 250.144 states, Where equipment is grounded and is supplied by separate connection
to more than one circuit or grounded premises wiring system, an equipment grounding
conductor termination shall be provided for each such connection as specified in 250.134 and
250.138.
12. Is a shower trim required on a recessed fixture installed 10’ high above an open shower
stall? (the fixture is rated for a damp location) Joe W
No.
410.10 (A) Wet and Damp Locations. Luminaires installed in wet or damp locations shall be
installed such that water cannot enter or accumulate in wiring compartments, lampholders, or
other electrical parts. All luminaires installed in wet locations shall be marked, “Suitable for Wet
Locations.” All luminaires installed in damp locations shall be marked “Suitable for Wet
Locations” or “Suitable for Damp Locations.”
(D) Bathtub and Shower Areas. No parts of cord-connected luminaires, chain-, cable-, or cordsuspended luminaires, lighting track, pendants, or ceiling-suspended (paddle) fans shall be
located within a zone measured 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the
top of the bathtub rim or shower stall threshold. This zone is all encompassing and includes the
space directly over the tub or shower stall. Luminaires located within the actual outside
dimension of the bathtub or shower to a height of 2.5 m (8 ft) vertically from the top of the
bathtub rim or shower threshold shall be marked for damp locations, or marked for wet
locations where subject to shower spray.
13. I have installed liquidtight flexible metal conduit to several RTU's (rooftop units). The space
above the ceiling is used for environmental air return. The inspector has asked me to replace it.
Can't it be used in this application? Sloop
No per 300.22(C)1
14. Can the refrigerator receptacle count for the wall space receptacle required by 210.52
Mullis
Yes, if it is a 20 amp small appliance circuit in the wall space and not serving countertop space.
15. Is the receptacle installation in the cabinet below a code violation? Miller
No, per the literal wording of 406.9(C)
(C) Bathtub and Shower Space. Receptacles shall not be installed within or directly over a
bathtub or shower stall.
A bathtub space includes the footprint of any platform it may be installed in or sitting on.
16. Can I run two 2-wire cables to a detached garage and use the neutral in one of the cables
and use the other cable for hot conductors of a multi-wire circuit? Barnes
No, per 300.3(B)
NEXT MEETING:
Contractors – Wednesday September 11, 2013
Inspectors – Wednesday July 10, 2013