Transcript IAEI EASTERN SECTION

REVIEW OF CODE BREAKFAST QUESTIONS
Brought to you by fellow members who
attended the Section Meeting
Do the requirements of 310.10(C) apply to
underground communication wires and
cables entering buildings?
 2008 NEC – 310.10(C) does not exist
 2008 NEC 310.8(C) refers to Wet Locations
 2008 NEC 800.47 does not state that the
requirements of 310.10(C) do not apply
 Chapter 8 is a stand-alone chapter. It is
reasonable to assume that nothing in
Chapter 3 applies to these installations
unless specifically referenced – See 90.3
 2011 NEC 800.47 does add the language
that the requirements of 310.10(C) DO NOT
apply
 Why was this added?
 Are ceiling insert fans, wall insert fans, and
ceiling insert fan/light combinations, that are
intended to be mounted over bathtubs,
showers, or within the zone above a bathtub
or shower area (as defined in 410.10(D))
required to be GFCI protected?
 The zone described in 410.10(D)
 3 feet horizontally
 8 feet vertically
 From the top of the bathtub rim or shower
stall threshold
 Yes, GFCI protection is required as per the
listing of the product
 UL White Book – Product Category GPWV
 Is usually printed in the instruction sheet
Is the Grounding Electrode Conductor (GEC)
permitted to occupy the same raceway with
branch circuit conductors?
 Example – A run of 1” EMT leaves the panel
with four 12 AWG branch circuit conductors
and one 6 AWG bare GEC
 At a junction box near the ground rod, the 6
AWG exits the raceway/box system and
travels down the wall to the ground rod
 Can the conductor be in this raceway?
 A – Yes! It is not prohibited
 What other rules must we follow?
 Table 1 Chapter 9 – Conduit fill
 250.64(E) – Bonding of ferrous enclosures for
GECs
2011 NEC – 695.6(D) adds Electrical Metallic
Tubing as a permitted wiring method from
the Fire Pump Controller to the Pump Motor.
Does the same apply to the control circuit
wiring?
 2011 NEC
 NO!
 695.14(E)
 A proposal is needed to correct this
If an enclosure is rated Type 2 or 3R, may
drainage openings be field installed, or must
they be factory provided?
 According to UL, either method is acceptable
 Many enclosures do come with knock-outs
intended to be used as weep holes
 Others do not, but a hole can be drilled in the
field to provide this feature
 Always follow instructions
Does the NEC permit using the same
grounding electrode for two separate
systems with two different voltage ratings,
such as 120/240 and 480/277Y?
 It is permitted
 Actually, it is mandated
 Question - In health care facilities is ground fault
protection for operation of service and feeder
disconnecting means required to be fully
selective such that the feeder device but not the
service device shall open on ground faults on the
load side of the feeder device. Is a six cycle
minimum separation between service and feeder
ground fault tripping bands required?
 First part – Yes, 2 levels of ground fault
(service main and branch) are required in a
health care facility. This requirement makes
sure that the main does not open in the
event of a ground fault downstream of a
feeder device. This minimizes the disruption
to critical circuits in a health care facility.
 Second part – Maybe. The 2011 NEC was changed
to recognize the fact that newer solid state tripping
devices do not require the 6 cycle separation for
coordination required by older analog devices.
However, the manufacturer and the device trip
curves still needs to be consulted in case the
tolerances still require that separation for
coordination.
New solid
state
breaker on
left. Old
ground
fault relay
on right.
New device ground fault trip
curve, narrow band, can be
coordinated without 6 cycle
separation.
Old device ground fault trip
curve, wide band, not as
accurate, 6 cycle separation
for coordination required
Will the Code permit Decepticons to alter
their appearance during a...
 Sorry, wrong Transformers…
 Will the Code permit the installation of the
primary and secondary conductors of an
indoor transformer in the same raceway?
 If all conductors are operating at 600 volts or
under…..
 Then yes, it is permitted
 310.3(C)(1) – 2011 NEC
 If any conductors are over 600 volts…
 Then, no, it is not permitted
 310.3(C)(2) – 2011 NEC
Where the voltage between service
conductors does not exceed 300 volts and
the roof is guarded or isolated, may a
reduction to 3 feet of clearance from the roof
be permitted?
 2008 NEC – No!
 No such exception exists
 2011 NEC – Yes!
 The exception was added to this edition of
the code
 A good idea?
Does the same apply to Article 225 Outside
Branch Circuits & Feeder installations?
 2008 & 2011 NEC
 The language is in neither
 A proposal is needed to make the language
in Article 225 uniform with Article 230
 Where conductors of more than one PV
system occupy the same junction box or
raceway with removable covers, are AC and
DC conductors of each system required to
be grouped separately by wire ties or similar
means?
 2008 NEC – No such requirement exists
 2011 NEC – Yes – 690.4(B)(4)
 Grouped once and then every six feet
Do the equipotential bonding requirements
for perimeter surfaces in 680.26(B)(2) apply
to a listed, self-contained spa or hot tub
installed above a finished floor?
 In the previous picture, it is clear that
bonding would not help
 You can’t fix stupid…
 A new Exception in 680.43 relaxes the rules
for equipotential bonding for INDOOR
installations above a finished floor.
 The bonding requirements in 680.26(B)(2)
DO NOT apply
What do the letter codes that designate
various insulation types mean? What exactly
is THHN?
 The letter “R” represents a 60° C
temperature rating, such as RW
 The letter “T” represents a thermoplastic
insulation with a 60° C temperature rating,
such as TW
 The letter “W” represents an insulation
suitable for wet locations, such as TW
 The letter “N” represents a nylon outer
jacket, such as THHN

 The letter “X” represents a conductor coated
with a cross-linked polymer, such as XHHW
 A “-2” designation at the end of the identifier
string indicates that the conductor is suitable
for use at 90º C in both wet and dry
locations, such as THWN-2
 Each “H” adds 15º C to the temperature
rating of a conductor
 Example THW
 T = thermoplastic 60º C
 H = add 15º C
 W = wet locations
 THW = thermoplastic 75º C wire suitable for
wet locations
 Example THHN
 T = thermoplastic 60º C
 H = add 15º C x 2 = 30º C
 N = nylon outer jacket
 THHN = thermoplastic 90º C wire with a
nylon outer jacket
 Example THWN
 T = thermoplastic 60º C
 H = add 15º C
 W = wet locations
 N = nylon outer jacket
 THHN = thermoplastic 75º C wire with a
nylon outer jacket suitable for wet locations
 THWN-2
 Thermoplastic 90º C with a nylon outer
jacket suitable for use in wet locations
 Example XHHW
 X = cross-linked polymer 60º C
 H = add 15º C x 2 = + 30º C
 W = wet locations (take away one H)
 XHHW = cross-linked polymer 90º C wire in
dry locations and 75º C in wet locations
 XHHW-2 = 90º C rated in wet locations
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