IAEI Questions
Please Note: All answers given for the questions below
are for discussion purposes ONLY, and are not to be taken as formal
interpretations by the
The Minnesota Chapter would
like to thank the Code Panel members, Michael Buck, Tom Lichtenstein, Mark
Earley and Mike Forister for taking time from their busy schedules to
participate in this panel, plus the time they have used to research and answer
these questions.
1. Is
GFCI protection required for a 125-volt, single-phase, 15 amp receptacle, installed
outdoors at a place of business that is normally not open to the general public?
The company has multiple employees, but there are no gates or fences to
preventing access to the building.
In the 2002 Code, GFCI protection was required for the
exterior receptacle outlets installed in other than dwelling units for rooftop
receptacles.
In the 2005 Code 422.51, Cord-and-Plug-Connected
Vending Machines was added. The new
section requires cord-and-plug-connected vending machines manufactured or
re-manufactured on or after
To accomplish this 210.8(B) (4) and (5) added the GFCI
requirement for receptacles installed outdoors.
Specifically 210.8(B) (4) applies to outdoor locations in public spaces
and defines a “public space” as a space that is for use by or accessible to the
public. Since the place of business in
the question is not guarded by locked doors or fences, GFCI protection would be
required.
2. Are
energy management and communication cables (CL 2 cable) required to be plenum
rated when installed inside a listed, nonmetallic, plenum-rated signaling
raceway in the space over a return-air (plenum) ceiling?
Yes, 725.61(A) only permits type
CL 2P and CL 3P cables in these raceways.
3. Can
THHN grounding electrode conductor be installed in a listed nonmetallic plenum
signaling raceway installed in the space over a hung ceiling used for
environmental air handling purposes? Can the same conductor be installed in
EMT?
Article
760.3(B)((Fire Alarms)) refers to the requirements of Article 300.22 for
installations in Ducts, Plenums, and other Air Handling Spaces. Article
300.22(C) specifies the acceptable wiring methods in the cavity above the
dropped ceiling where the cavity is used for environmental air. The wiring
methods do not include listed nonmetallic plenum signaling raceway. EMT is an
acceptable wiring method.
Listed
nonmetallic plenum communication raceway is allowed in plenums for communication
circuits according to Article 800.154(A) using only Type CMP cable.
4.Is
GFCI protection required for a 125-volt 20 amp receptacle that is installed 15
feet above the sidewalk under the canopy (for holiday lights) at a retail
store?
No. Section 210.8(B)(4) requires a GFCI for other
than dwelling units outside in public spaces where accessible to the
public. Because this receptacle is 15
feet in the air and would need a ladder to reach it, it would not comply with
the definition of accessible in Article 100 because of elevation.
5.Would
a 20 amp 125-volt receptacle used to provide power for a pump-motor that pumps
water out of ponds, lakes or rivers, need to be GFCI protected when used to
provide water to a sprinkler system outdoors at a office building?
Note:
The receptacle is not accessible to the public, but is within the electrical
datum plain of the pond, lake or river. Could the pump be direct-wired (without
the receptacle)?
In the 2002 Code, GFCI protection was required for the
exterior receptacle outlets installed in other than dwelling units for rooftop
receptacles.
In the 2005 Code 422.51, Cord-and-Plug-Connected
Vending Machines was added. The new
section requires cord-and-plug-connected vending machines manufactured or
re-manufactured on or after
To accomplish this 210.8(B) (4) and (5) added the GFCI
requirement for receptacles installed outdoors.
Specifically 210.8(B) (4) applies to outdoor locations in public spaces
and defines a “public space” as a space that is for use by or accessible to the
public. Since the place of business in
the question is not guarded by locked doors or fences, GFCI protection would be
required.
6.Would
Section 700.27 require a 2000 amp GFPE service at an office building to be
selectively coordinated with the 1200 amp feeder that subsequently feeds a 200
amp feeder?
Note: The two hundred-amp feeder runs to a transfer
switch (also supplied by an emergency generator) that feeds a main lug 200 amp
emergency lighting panelboard with 20 amp lighting circuits used to supply
egress lights. The two hundred-amp breaker in the generator is selectively
coordinated with the 20 amp emergency lighting circuits.
The intent of this section is to
isolate the fault within the emergency system so that the entire system is not
affected. Coordination within the
emergency system is what is intended here.
This section only applies to the emergency system, not to the service.
7.How
much detail is required to comply with the requirement in 408.4 to fill out the
panel directory? Could each of the two-kitchen appliance circuits be identified
simply as “appliance”? Could each of the two bedroom AFCI breakers be simply
marked “bedrooms 1 & 2” “bedrooms 3 & 4”?
The requirement is that each
circuit shall be identified as to its clear, evident, and specific purpose or
use. The identification shall include sufficient detail to allow each circuit
to be distinguished from all others. It may not be clear to anyone which
bedroom is 1, 2, 3, or 4. It should be made clear where the rooms are, for
instance: Northwest bedroom, southwest bedroom, etc. Kitchen appliance circuit
may be specific enough.
8.When
fixture whips containing a white and a black conductor are installed in a
building with two nominal voltage systems and used to supply both 120 and 277
volt luminaires, is re-identification required for the black conductor when
used on an ungrounded circuit that is other than a black? If so, to what extent? Is re-identification
required for the white conductor when used on a 277 volt lighting circuit?
Note: The current identification for conductors in
the building is 120/208 A phase is
black, B phase is red and C phase is blue and grounded conductor is white. The
277/480 is A phase is brown, B phase is orange and C phase is yellow and
grounded conductor is gray.
Yes and Yes sometimes. For the black conductor, Section 210.5(C)
requires where the premises wiring system has branch circuits supplied from
more than one nominal voltage system, each ungrounded conductor of a branch
circuit, where accessible, shall be identified by system. The means of
identification shall be permitted to be by separate color coding, marking tape,
tagging, or other approved means and shall be permanently posted at each
branch-circuit panelboard or similar branch-circuit distribution equipment.
For the White Conductor,
200.6(D) requires that the grounded conductor of different systems be
identified where the ungrounded conductors of both system are present in the
same raceway, enclosure, cable or equipment.
And that the identification means to differentiate between systems be
permanently marked at each branch circuit panelboard.
9.Is AFCI protection required
for a 125-volt 15 amp outlet in a guest suite bedroom? Would it make a
difference if it had a kitchen in the suite?
210.12(B) requires AFCI protection in dwelling unit
bedrooms. A kitchen in a hotel room can
make it a dwelling unit. See article 100
definition of a dwelling unit. See also
Section 210.18.
10.Where is AFCI protection
required in an efficiency apartment?
Provided the “efficiency
apartment” meets the definition of a “dwelling unit”, AFCI protection is
required for the bedroom according to Article 210.12. If the living area and
the bedroom are one and the same, AFCI protection would be required.
11.Is
NM cable considered secured or supported when installed behind a 1 5/8 inch
deep narrow strip of Styrofoam?
Note:
The installation practice was to remove a 2 inch deep narrow strip of Styrofoam
from a pored concrete wall, the NM cable is then installed and the Styrofoam is
trimmed from 2 inches to 1 5/8 inches deep and reinstalled and friction held in
place until wall covering is installed.
Would
it make a difference if I were to discard the 2- inch strip of Styrofoam and
re-foam the NM cable so it is a minimum of 1 ¼ inch back from the face of the
Styrofoam?
There are three basic Code requirements to be
met. The cable must be protected from
physical damage, supported, and secured to the outlet box.
300.4(E) This section relates to protection from
physical damage and allows the cable to be installed in shallow grooves without
additional protection provided it is maintained at least 1¼ inches back from
the face of the groove. Care must be
taken to ensure the cable remains at least 1¼ inches back.
314.17(B) & (C) require all permitted wiring
methods to be secured to the (outlet) box.
There is a limited exception for single gang, nonmetallic boxes.
334.30 requires the cable to be secured and supported
using an approved means at intervals not exceeding 4½ feet and within 12 inches
of each outlet box. Approved is
acceptable to the authority having jurisdiction. I would accept the minimal support provided
by the Styrofoam (raceway) in addition to the securing the cable to the outlet
box.
The use of expanding foam is only appropriate where
the foam will not have a deteriorating effect on the cable. This would permit some discretion in allowing
the foam to replace the strip of insulation that was removed. Personally I would not accept this type of
installation where I could not see the cable at the rough in inspection.
12.What
minimum size conductors with a rating of THHN/THWN are required to a panelboard
with a 400 amp main breaker?
Note:
The panelboard is fed from a transformer with a secondary voltage of 120/208
three phase wye, with secondary conductors 20 feet long. The primary is 480
volts three phase protected at 200 amps with 3/0 wire.
240.21(C) can’t round up overcurrent
protection for transformer secondary conductors. Therefore, for this application, the minimum
conductor size permitted is 600 kcmil
13.Must
the supply water piping to a hydromassage bathtub be bonded when there is no
lug on the motor and the pump motor is double insulated? Must the supply water
piping be bonded when a hydromassage bathtub has a lug on the motor and the
pump motor is supplied wired with a three-conductor cord? If bonding is
required, exactly what and how must it be tied together? \What bonding is
required if the supply is plastic?
Note:
The tubs re-circulating system is plastic piping in all the above scenarios.
NEC Section 680.74 requires that
metal piping systems and all grounded metal parts in contact with the
circulating water shall be bonded together with a min no. 8AWG. Copper
insulated covered or bare. If the water
supply is plastic, there is nothing to bond to, if the pump is Double Insulated
there is no grounded parts in contact with the water and no bonding is
required.
14.If I
construct my own equipotential bonding grid with a # 8 bare solid copper
conductor around a swimming pool using a one foot on center checker board
pattern, the #8 conductor crosses over itself approximately 750 times, do I
need to connect theses points of crossing together and if so, do they have to
all be connected using a listed means (split bolt connectors approved for
direct burial)?
Yes, Article 680.26(C)(3)
requires the grid to be bonded at all points of crossing. The connections shall
be made according to Article 250.8, which requires exothermic welding, listed
pressure connectors, listed clamps or other listed means.
15.What
minimum size grounded conductor (neutral) is required for a 11 ampere
calculated load on the grounded conductor of a 50 amp feeder wired with # 8
ungrounded conductors, and a #10 equipment
grounding conductor all in PVC?
There are three basic Code requirements to be
met. The cable must be protected from
physical damage, supported, and secured to the outlet box.
300.4(E) This section relates to protection from
physical damage and allows the cable to be installed in shallow grooves without
additional protection provided it is maintained at least 1¼ inches back from
the face of the groove. Care must be
taken to ensure the cable remains at least 1¼ inches back.
314.17(B) & (C) require all permitted wiring
methods to be secured to the (outlet) box.
There is a limited exception for single gang, nonmetallic boxes.
334.30 requires the cable to be secured and supported
using an approved means at intervals not exceeding 4½ feet and within 12 inches
of each outlet box. Approved is
acceptable to the authority having jurisdiction. I would accept the minimal support provided
by the Styrofoam (raceway) in addition to the securing the cable to the outlet
box.
The use of expanding foam is only appropriate where
the foam will not have a deteriorating effect on the cable. This would permit some discretion in allowing
the foam to replace the strip of insulation that was removed. Personally I would not accept this type of installation where I could not
see the cable at the rough in inspection.
16.How do you size a common
grounding electrode conductor run to two 30 KVA transformers with derived
conductors of # 1 on the secondary feeding 125 amp main breaker panelboards?
No. 6 Copper or No. 4 Alumnium for the tap conductors.
250.30(A)(4)
(4) Grounding Electrode Conductor, Multiple Separately
Derived Systems. Where more than one separately derived system is installed, it
shall be permissible to connect a tap from each separately derived system to a
common grounding electrode conductor. Each tap conductor shall connect the
grounded conductor of the separately derived system to the common grounding
electrode conductor. The grounding electrode conductors and taps shall comply
with 250.30(A)(4)(a) through (A)(4)(c).
(a) Common
Grounding Electrode Conductor Size. The common grounding electrode conductor
shall not be smaller than 3/0 AWG copper or 250 kcmil aluminum.
(b) Tap
Conductor Size. Each tap conductor shall be sized in accordance with 250.66
based on the derived phase conductors of the separately derived system it
serves.
17.Can I use three single
pole breakers to feed permanently connected free standing type office
partitions with three #12 ungrounded conductors, a #12 equipment grounding
conductor and a #10 common neutral all in liquid-tight flexible metal conduit?
No, Section 605.6 requires that multiwire circuits
feeding office panels be provided with a means to simultaneously disconnect all
ungrounded conductors at the panelboard where the branch circuit
originated. You either have to use a 3
phase breaker or handle tie appropriately rated single pole breakers.
18. Does Section 210.8(A) (7)
apply to receptacles in dedicated spaces, such as the laundry receptacle if
it’s behind the clothes washer or dryer?
Yes, all 125 volt, 15 or 20 amp receptacles installed
within 6’ of the sink must be protected by a GFCI. There is no exception to
allow dedicated spaces, non-readily accessible, etc.
19.Does a metal cut-in box
installed in a ceiling for the installation of a smoke detector have to be
grounded when fed from a two-wire, ungrounded system in an existing dwelling?
Maybe yes, but probably not.
As a point of clarification to the question, the
premise wiring system is grounded and the branch circuit wiring method is
In general,
Article 250.86 requires metal enclosures and raceways for other than service
conductors to be grounded. Exception
No.1 exempts metal enclosures and raceways for conductors added to existing
installations of open wire, knob and tube wiring, and nonmetallic-sheathed
cable from the previously stated grounding requirements where the enclosures or
wiring methods comply with the (1) through (4) as follows:
(1)
Do not provide an equipment ground
(2)
Are in runs of less than 25 feet
(3)
Are free from probable contact with ground, grounded
metal, metal lath, or other conductive materials
(4)
Are guarded against contact by persons
The nonmetallic smoke detector should adequately guard
the metal box from contact by persons and as stated, the branch circuit wiring
method does not provide an equipment ground.
If the metal box does not contact grounded metal, metal lath or other
conductive material and the circuit extension is less than 25 feet, the metal
box would not have to be grounded.
It should be pointed out that smoke detectors shall be
provided with power from a central source and smoke detectors shall be
interconnected in such a manner that all smoke detectors will sound an alarm
when one smoke alarm goes into alarm.
In addition, when interior alterations, repairs, or
additions requiring inspections occur, or one or more sleeping rooms are added
or created in existing dwellings, the dwelling shall be provided with smoke
detectors as required for new construction.
Given these requirements, the length of the run will
likely exceed 25 feet and not meet the criteria of the exception. The Code requirements are the same applying
either the 2002 or 2005 NEC.
20.When replacing metal
luminaires in existing structures that do not have equipment grounding means in
the box, the luminaires are not accessible from grade or grounded surfaces,
what if any additional requirements apply?
Per 410.18(B), exc. 2, the circuit must be protected
by GFCI.
21. If I am wiring a townhome
that will have a stackable 240-volt washer/dryer installed, will I still have
to install a 20-ampere, 125-volt laundry receptacle? The stackable unit will
not use the 125-volt circuit, and it’s just a waste of money.
Yes, Article 210.52(F) requires at least one
receptacle outlet for the laundry. A stackable washer could be replaced with a
120 volt appliance.
22. What exactly is a
“vending machine” as described in Section 422.51? Is it food vending only, or can
it be other types of similar machines?
It is not food machines only, it is any kind of
vending machine. Presently, the
standards for these types of machines have not adopted requirements for the
GFCI in the cord yet. So GFCI
receptacles for cord-connected vending machines are necessary to comply with
this requirement.
23. If I install a 125-volt
electric baseboard heater on a 20-amp circuit in a bedroom, does this circuit
need to be AFCI-protected?
Yes.
As a point of clarification, the nominal voltage of
the NEC is 120 volts, and Code requirements are not waived if the actual
voltage of the circuit varies by a few volts.
Article 210.12 requires arc-fault circuit interrupter
protection for all 120-volt, single-phase, 15- and 20-ampere branch circuits
supplying outlets installed in dwelling unit bedrooms.
The NEC defines an outlet as a point on the wiring
system at which current is taken to supply utilization equipment and
utilization equipment as equipment that utilizes electric energy for electronic,
electromechanical, chemical, heating, lighting, or similar purpose. There are no exceptions that apply. The requirements were the same in the 2002
NEC.
24. Why doesn’t my brand-new,
expensive AFCI tester always trip AFCI breakers? If it doesn’t trip, is the
breaker faulty?
AFCI
indicators operate by producing a waveform similar to an arc fault. However,
because they cannot produce an actual arc fault, an AFCI indicator may not trip
every available AFCI.
Therefore,
if an AFCI indicator plugged into a receptacle protected by an AFCI does not
trip the AFCI, it does not mean that the AFCI protecting the circuit is
defective and needs to be replaced. When this situation occurs, you should push
the "Test" button provided as an integral part of the AFCI itself. If
the integral test button does not trip the AFCI circuit breaker, it should be
replaced.
To
notify users of this product limitation, Underwriters Laboratories Inc.
requires AFCI indicators to be marked or be provided with instruction manuals
that state the following or equivalent:
CAUTION: AFCIs recognize characteristics unique to
arcing, and AFCI indicators produce characteristics that mimic some forms of
arcing. Because of this the indicator may give a false indication that the AFCI
is not functioning properly. If this occurs, recheck the operation of the AFCI
using the test and reset buttons. The AFCI button test function will
demonstrate proper operation.
25. A feeder tap consisting
of 500KCMIL copper conductors is connected to a panelboard with a 400 ampere
main breaker. Is this a legal installation?
No, you are not allowed to round up to the next
overcurrent device according to Article 240.21(B). 500 KCMIL copper conductors
are rated 380 amps for 75-degree conductors. The maximum overcurrent device
would be 350 amps.
26. If I have both a water
pipe grounding electrode and a concrete-encased reinforcing rod electrode in
the building footings, do I still need to drive a ground rod?
250.53(D)(2)-Supplement
water pipe electrode per (A)(2) to (A)(7)
The concrete encased electrode satisfies this requirement.
27. Can I run branch circuits
overhead between trees for Christmas lights?
Yes, as of next Christmas.
In the 2002 NEC, 527.4(J) prohibited the use of
vegetation such as trees for the support of overhead spans of branch circuits
and feeders.
In the 2005 NEC, Article 527. Temporary Installations,
was relocated to Article 590 and renumbered.
An exception was added to 590.4(J) to allow the branch circuits
supplying holiday lighting to be supported by trees where the conductors or
cables are arranged with proper strain relief devices, tension take-up devices,
or other approved means to avoid damage from the movement of the trees. Temporary electrical power and lighting
installations for holiday decorative lighting shall be permitted for a period
not exceeding 90 days.
It should be noted that the exception that allows
branch circuit conductors to be supported by trees does not apply to temporary
installations for construction, remodeling, maintenance, or similar activities
28. Is it required to derate
conductors in raceways exposed to direct sunlight?
310.10 Yes if operating temperature is exceeded. See also 310.10, FPN No. 2.
29. In the past, any splices
in the grounding electrode conductor(s) had to be done by some type of
irreversible splice. If you use the busbar connection point now allowed by
Section 250.64(C), do these conductors have to be permanently attached to the
busbar, or is bolting connectors acceptable? If bolted are acceptable, then can
the connectors themselves be of the “set screw” type, or must they be
compression type?
This is not considered a splice. Article 250.64(C)(3)
allows the use of a busbar to connect bonding jumpers and grounding electrode
conductors. It allows the use of listed connectors or exothermic welding.
Either listed setscrew type or compression connectors would suffice.
30. In Section 210.18, does a
microwave mounted above a countertop with a cord-and-plug connection qualify as
“...permanent provisions for cooking”?
No, Extended-stay hotels and motels are often equipped
with permanent provisions for cooking and countertop areas such as a cook top
range mounted in the counter. A portable microwave oven is not considered to be
a permanently installed cooking appliance.
31. In an efficiency
apartment, which is one room with the bed, kitchen area and living area in it,
which receptacles must be on the Small Appliance Branch Circuits? Which
receptacles must be AFCI-protected?
If an area within a building or structure meets the
definition of a dwelling it must be wired in accordance with the requirements
for a dwelling including the required branch circuits, minimum number and
placement of receptacle outlets, required lighting outlets and switching locations,
GFCI, and AFCI protection.
A single, 15-ampere, general lighting circuit can
serve an area up 600 square feet. That
is an area equal to 20’ by 30’. One such
circuit with an arc-fault circuit interrupter protection would likely be
adequate.
Receptacle outlets that could be reasonably expected
to serve the kitchen and dining area would be required to be supplied by two
small-appliance branch circuits. GFCI
protection would be required for receptacles installed to serve countertop
surfaces.
As an inspector, I would not require AFCI protection
for the small-appliance branch circuits for the same reason I would not
require, or permit the receptacles adjacent to the bed to be supplied by a
20-ampere, small-appliance branch circuit.
32. What are the exit
requirements for a room containing a 2,000-ampere switchboard that is 5’ high
and 3’ wide? If a door was on the wall opposite the switchboard, and you had to
go partially around a column to get to the door, would that qualify as an
“unobstructed exit”?
110.26(C)(2) Exit
requirement is now based on rating of equipment rather than its physical
size. Hard to say. I wouldn’t consider it unobstructed. Therefore, I would not consider a single exit
to be adequate.
33. The local inspector keeps
getting complaints that the refrigerators being used by vendors at the County
Fair keep tripping the GFCI-protected receptacles. Is it a requirement that
these refrigerators be on a ground-fault? Don’t they keep “nuisance tripping”
the GFCI?
Yes, they are required to be GFCI protected by Section
210.8(B)(2) or (4) depending on the set up at the fair. If the GFCI’s are tripping, they are not
nuisance tripping, they are tripping for a reason, there is excessive leakage current
coming from the refrigerators meaning there is some type of fault in the
equipment. The GFCI is doing exactly
what it is intended to do.
34. The local inspector
“red-tagged” the temporary wiring for a new store of type III construction,
because he said Romex wasn’t allowed to be run in the open according to Section
334.10(3). Is he correct?
Article 590.4(C) clarifies that NM cable may be used
for temporary wiring in any dwelling, building or structure without any height
limitation or limitation by building construction type and without concealment
within walls, floor, or ceilings.
35. A permanent generator is
installed on the ground outside a building. The generator feeds a computer room
and the air conditioning equipment for the building. If the generator is
installed inside a locking enclosure, does there have to be a disconnecting
means on the exterior of the building for the feeder?
Loads supplied by optional standby systems are loads
that if lost can cause physical discomfort, serious interruption of industrial
processes, damage to process equipment, or disruption of business. The loads listed in the question seem to fit
these requirements.
A generator set typically has an integral circuit
breaker that provides overcurrent
protection for the generator as well as providing overcurrent protection for
properly sized conductors serving the load connected to the generator.
Section 702.11 was added in the 2005 Code which allows
a readily accessible disconnecting means on, or part of an outdoor generator
set to serve as the disconnecting means required by 225.31 when installed
within sight of the building or structure supplied. To be considered within sight the equipment
must be visible and not more than 50 feet.
Is the generator set considered readily accessible
when installed within a locked enclosure?
Ready access is not considered to be denied by a locked door or
enclosure. Equipment would not be
considered readily accessible if a snow blower, snow shovel, or ice pick were
required to get to the disconnecting means.
Ready access in not denied by a lock when authorized
persons with keys are readily at hand.
An additional disconnecting means would not be required if the generator
was otherwise readily accessible.
36. A new home has a large
shelf for a television set mounted near the ceiling over the hydromassage
bathtub. There is no shower on this tub. Is it permissible to have a receptacle
by the shelf for the TV? Must it be GFCI-protected? If the shelf is metal, must
it be bonded to the bathtub?
406.8(B)(1)
406.8(C)-Receptacle not permitted in that space
210.8(A)(1)requires bathroom receptacles to be GFCI
protected.-But not permitted in that space.
680.74-Bonding to bathtub not required.
37. In an existing
multi-tenant building with a 3,000-ampere 277/480-volt service, there is a
proposal for a local health-care provider to put in a “day-surgery” center.
This center would have some of the patients put under general anesthetic for an
operation. The main service disconnect has GFPE. If this tenant is allowed to
go into the building, does this mean that the feeder to each tenant will now
have to be retrofitted with an additional level of GFPE per Section 517.17?
Yes, this would be a requirement according to Article
517.17(B).
38. Does the NEC have a
required use of type “CI” (Circuit integrity) cable, or does it just recognize
it?
The NEC does not require Circuit Integrity or CI
cable, however, it is permitted to ensure critical circuit survivability for
continued circuit operation for a specified time under fire conditions in
applications as in Section 725.61(H) and 725.82(F) and in Article 760 for fire
alarm circuits and in NFPA 72.
39. Where is the ground
detector mentioned in Section 250.21 supposed to be located? At the source? At
a normally-occupied location?
The code does not specify a location. It is intended to be located where it can be
readily seen.
40. Is it required to have a
“bubble-style” “in-use” cover on a receptacle in an indoor car wash?
Yes, Section 406.8(B)(1) dropped the term outdoors
from the requirement in the 2005 NEC and requires 15 and 20 A, 125 and 250V
receptacles installed in wet locations be provided with bubble covers
regardless of indoors or out.
41. What types of raceways
are acceptable for the underground run from a gas pump on the island at a
service station to the interior of the building?
Article 514.8 specifies that the underground wiring
shall be installed in threaded rigid metal conduit or threaded steel
intermediate metal conduit. Exception 2 allows rigid nonmetallic conduit with
at least 2 feet of cover. The last two feet from emergence must be threaded
rigid metal conduit or threaded steel intermediate metal conduit.
42. Where does the bonding
conductor for a swimming pool have to terminate? In a subpanel? Or all the way
back to the service equipment?
The intent of the bonding requirements is to establish
an equipotential plane to limit the voltage between all non-current-carrying
parts of electrical and nonelectrical equipment in the pool area. A Fine Print Note to 680.26 explains that the
only function of the 8 AWG or larger conductor is equipotential bonding to
eliminate the voltage gradient in the pool area.
Where metal parts of electrical equipment are bonded,
it has the effect of connecting the equipotential plane to the premise wiring
system equipment grounding conductor but the 8 AWG or larger solid copper
bonding conductor is not required to be extended or attached to any remote
panelboard, service equipment, or any electrode.
43. Can a cable tray used for
service conductors contain other conductors such as feeders?
230.44-Cable tray is not permitted unless there is a
solid fixed barrier of material (compatible with the cable tray) to separate
the service conductors from the other conductors.
44. Has any manufacturer come
out with the thinner, stronger nail plate that is now allowed in Section
300.4(A)(1) Ex.2? Is there a UL standard for such a product?
Not yet, no manufacturer has submitted a thinner plate
for Listing. UL does have Listed plates
under the category Conduit and Cable Hardware, (DWMU) located on page 21 in the
2004 White Book. UL 2239 is the Standard
for Conduit and Cable Hardware, presently there are no requirements in the
standard for plates less than 0.0625 in. thick.
If a manufacturer would submit for a Listing we would establish Listing
criteria to evaluate the thinner plates.
45. Is a switch with an
internal neon pilot light still considered a “Device” under the definition in
Article 100, even though it does utilize a small amount of power?
Here is a proposal I am submitting for the 2008
Code. The definition of a device is a
unit of an electrical system that is primarily intended to carry or control
utilize electric energy. A device may
utilize incidental energy to facilitate its operation.
By definition, a controller is a device or group of
devices that serves to govern, in some predetermined manner, the electric power
delivered to the apparatus to which it is connected. Many types of devices and controllers such as
lighting dimmers, magnetic starters, variable frequency drives, and
programmable controllers consumer electrical power to facilitate their
operation as well as generate incidental heat losses due voltage drop across
semiconductor junctions.
Simply adding the sentence “A device may utilize
incidental energy to facilitate its operation” to the current definition
clarifies this issue.
46. In a restaurant, there is
cooking in “kitchen” area, plus they have a salad bar with some 120-volt
heating appliances plugged in. There is also a “drink bar” with a soda pop
dispenser powered at 120-volts. Where is the “kitchen” area for purposes of
enforcing 210.8(B)(2)? Would it include the salad bar and drink dispenser?
According to Article 210.8(B)(2) a kitchen is an area
with a sink and permanent facilities for food preparation and cooking. A salad
bar and the soda pop dispenser would probably not meet the definition. This
would be a call shot of the AHJ at to where the “kitchen” ends.
47. A 120-volt, 20-ampere
receptacle is installed behind a very large, heavy freezer in a restaurant
kitchen. Does this receptacle need to be GFCI-protected?
Yes.
Section 210.8(B)(2) was new in the 2002 Code and
required all 15- and 20-ampere, 125 volt receptacles in non-dwelling-type
kitchens to be GFCI protected. This
requirement applies to all 15- and 20-ampere, 125-volt kitchen receptacles,
whether or not the receptacle serves countertop areas. However, what actually constituted a kitchen
was not clear.
In the 2005 Code, a definition of a commercial and
institutional kitchen was added to 210.8(B)(2).
A kitchen is an area with a sink and permanent facilities for food
preparation and cooking.
Good design practices would provide the GFCI
protection in the branch circuit panelboard rather than at the receptacle.
48. Assuming that a furnace
and an air conditioner have exactly the same circuit requirements, can they
both be on the same circuit?
Yes. New
Section 422.12 Ex2 now allows this as long as the supply circuit is adequate
for both loads. These two loads would be considered noncoincident and should
never operate simultaneously.
49. A luminaire is listed for
use in a Class 1, Zone 0 location. Can this luminaire be used in a Class 1,
Zone 2 location instead?
Yes, Section 505.9(B)(1) permits Equipment that is
listed for a Zone 0 location shall be permitted in a Zone 1 or Zone 2 location
of the same gas or vapor, provided that it is installed in accordance with the
requirements for the marked type of protection.
50. If an isolated ground receptacle
is used in a health-care facility, does the isolated ground conductor count as
one of the two redundant ground paths for the receptacle?
No, Article 517.13(A) requires all branch circuits
serving patient care areas be provided with a ground path for fault current by
installation in a metal raceway system, or a cable having a metallic armor or
sheath assembly. The metal raceway system or metallic cable armor, or sheath
assembly shall itself qualify as an equipment ground return path in accordance
with 250.118.
Article 517.13(B) requires an insulated
equipment-grounding conductor to ground all fixed electric equipment likely to
become energized that are subject to personal contact. This would include
boxes. So, these two requirements must be met in addition to the isolated
ground.
Article 517.16 allows an isolated ground for
receptacles.