Transcript 2017 NEC Changes

Water Environmental Association of Texas
E&I Committee
2014
2017
90.3 Code Arrangement. This
Code is divided into the
introduction and nine chapters, as
shown in Figure 90.3. Chapters 1,
2, 3, and 4 apply generally;
Chapters 5, 6, and 7 apply to
special occupancies, special
equipment, or other special
conditions. These latter chapters
supplement or modify the general
rules. Chapters 1 through 4 apply
except as amended by Chapters 5,
6, and 7 for the particular
conditions. Chapter 8 covers
communications systems and
90.3 Code Arrangement. This
Code is divided into the
introduction and nine chapters, as
shown in Figure 90.3. Chapters 1,
2, 3, and 4 apply generally.
Chapters 5, 6, and 7 apply to
special occupancies, special
equipment, or other special
conditions and may supplement
or modify the requirements in
Chapters 1 through 7 .
2014
Accessible, Readily (Readily
Accessible). Capable of being
reached quickly for operation,
renewal, or inspections without
requiring those to whom ready
access is requisite to actions such
as to use tools, to climb over or
remove obstacles, or to resort to
portable ladders, and so forth.
2017
Accessible, Readily (Readily
Accessible). Capable of being
reached quickly for operation,
renewal, or inspections without
requiring those to whom ready access
is requisite to take actions such as to
use tools (other than keys), to climb
over or under, to remove obstacles, or
to resort to portable ladders, and so
forth. (CMP-1)
Informational Note: Use of keys is a
common practice under controlled or
supervised conditions and a common
alternative to the ready access
requirements under such supervised
conditions as provided elsewhere in
the NEC.
2014
2017
Building. A structure that
stands alone or that is cut
off from adjoining
structures by fire walls with
all openings therein
protected by approved fire
doors.
Building. A structure that
stands alone or that is
separated from adjoining
structures by fire walls.
2014
2017
No Definition
Field Evaluation Body
(FEB). An organization or
part of an organization that
performs field evaluations
of electrical or other
equipment.
2014
2017
No Definition
Field Labeled (as applied to
evaluated products). Equipment
or materials to which has been
attached a label, symbol, or
other identifying mark of an FEB
indicating the equipment or
materials were evaluated and
found to comply with
requirements
as described in an accompanying
field evaluation report.
2014 (PART I)
2017 (MOVED TO PART II)
Substation. An enclosed
assemblage of equipment
(e.g., switches, interrupting
devices, circuit breakers,
buses, and transformers)
through which electric
energy is passed for the
purpose of distribution,
switching, or modifying its
characteristics.
Substation. An assemblage
of equipment (e.g., switches,
interrupting devices, circuit
breakers, buses, and
transformers) through
which electric energy is
passed for the purpose of
distribution, switching, or
modifying its
characteristics.
2014
110.3 Examination, Identification,
Installation, and Use of Equipment.
(A) Examination. In judging equipment,
considerations such as the following shall
be evaluated:
(1) Suitability for installation and use in
conformity with the provisions of this
Code
Informational Note: Suitability of
equipment use may be identified by a
description marked on or provided with a
product to identify the suitability of the
product for a specific purpose,
environment, or application. Special
conditions of use or other limitations and
other pertinent information may be
marked on the equipment, included in the
product instructions, or included in the
appropriate listing and labeling
information. Suitability of equipment may
be evidenced by listing or labeling.
2017 (ADDED
INFORMATIONAL NOTE)
110.3 Examination, Identification, Installation,
Use, and Listing
(Product Certification) of Equipment.
(A) Examination. In judging equipment,
considerations such as the following shall be
evaluated:
(1) Suitability for installation and use in
conformity with the provisions of this Code
Informational Note No. 1: Equipment may be
new, reconditioned, refurbished, or
remanufactured.
Informational Note No. 2: Suitability of
equipment use may be identified by a
description marked on or provided with a
product to identify the suitability of the product
for a specific purpose, environment, or
application. Special conditions of use or other
limitations and other pertinent information may
be marked on the equipment, included in the
product instructions, or included in the
appropriate listing and labeling information.
Suitability of equipment may be evidenced by
listing or labeling.
2014
2017 (NEW SUBSECTION)
No Subsection
(C) Listing. Product testing,
evaluation, and listing (product
certification) shall be performed
by recognized qualified electrical
testing laboratories and shall be in
accordance with applicable
product standards recognized as
achieving equivalent
and effective safety for equipment
installed to comply with this
Code.
(Also a new Informational Note)
2014
2017
110.9 Interrupting Rating.
Equipment intended to interrupt
current at fault levels shall have
an interrupting rating at nominal
circuit voltage sufficient for the
current that is available at the line
terminals of the equipment.
110.9 Interrupting Rating.
Equipment intended to interrupt
current at fault levels shall have
an interrupting rating at nominal
circuit voltage at least equal to the
current that is available at the line
terminals of the equipment.
Equipment intended to interrupt
current at other than fault levels
shall have an interrupting rating
at nominal circuit voltage
sufficient for the current that
must be interrupted.
Equipment intended to interrupt
current at other than fault levels
shall have an interrupting rating
at nominal circuit voltage at least
equal to the current that must be
interrupted.
2014
2017 (NEW SUBSECTION)
No subsection
(D) Installation. Where a
tightening torque is indicated
as a numeric value on
equipment or in installation
instructions provided by the
manufacturer, a calibrated
torque tool shall be used to
achieve the indicated torque
value, unless the equipment
manufacturer has provided
installation instructions for an
alternative method of
achieving the required torque.
2014
110.16 Arc-Flash Hazard Warning.
Electrical equipment, such as
switchboards, switchgear,
panelboards, industrial control
panels, meter socket enclosures,
and motor control centers, that are
in other than dwelling units, and
are likely to require examination,
adjustment, servicing, or
maintenance while energized, shall
be field or factory marked to warn
qualified persons of potential
electric arc flash hazards. The
marking shall meet the
requirements in 110.21(B) and shall
be located so as to be clearly visible
to qualified persons before
examination, adjustment, servicing,
or maintenance of the equipment.
(2014 text was moved into a
subsection A and a new subsection
B was added)
2017
(B) Service Equipment. In other
than dwelling units, in addition to
the requirements in (A), a
permanent label shall be field or
factory applied to service
equipment rated 1200 amps or
more. The label shall meet the
requirements of 110.21(B) and
contain the following information:
(1) Nominal system voltage
(2) Available fault current at the
service overcurrent protective
devices
(3) The clearing time of service
overcurrent protective devices
based on the available fault current
at the service equipment
(4) The date the label was applied
(Exception and informational note 3
added
- next slide)
Exception: Service equipment labeling shall not be required
if an arc flash label is applied in accordance with acceptable
industry practice.
Informational Note No. 3: Acceptable industry
practices for equipment labeling are described in
NFPA 70E -2015 Standard for Electrical Safety in the
Workplace. This standard provides specific criteria for
developing arc-flash labels for equipment that
provides nominal system voltage, incident energy
levels, arc-flash boundaries, minimum required levels
of personal protective equipment, and so forth.
2014
110.21 Marking.
(A) Manufacturer’s Markings. The
manufacturer’s name, trademark,
or other descriptive marking by
which the organization responsible
for the product can be identified
shall be placed on all electrical
equipment. Other markings that
indicate voltage, current, wattage,
or other ratings shall be provided as
specified elsewhere in this Code.
The marking or label shall be of
sufficient durability to withstand
the environment involved.
2017 (TITLE CHANGE AND
NEW SUBSECTION)
(A) Equipment Markings.
(2) Reconditioned Equipment.
Reconditioned equipment shall be
marked with the name, trademark,
or other descriptive marking by
which the organization responsible
for reconditioning the electrical
equipment can be identified, along
with the date of the reconditioning.
Reconditioned equipment shall be
identified as “reconditioned” and
approval of the reconditioned
equipment shall not be based solely
on the equipment’s original listing.
2014
2017
(B) Field-Applied Hazard
Markings. Where caution,
warning, or danger signs or
labels are required by this
Code, the labels shall meet the
following requirements:
(1) The marking shall
adequately warn of the hazard
using effective words and/or
colors and/or symbols.
(B) Field-Applied Hazard
Markings. Where caution,
warning, or danger signs or
labels are required by this
Code, the labels shall meet the
following requirements:
(1) The marking shall warn of
the hazards using effective
words, colors, symbols, or any
combination thereof.
2014
2017
110.24 Available Fault
Current.
(A) Field Marking. Service
equipment in other than
dwelling units shall be legibly
marked in the field with the
maximum available fault
current. The field marking(s)
shall include the date the faultcurrent calculation was
performed and be of sufficient
durability to withstand the
environment involved.
110.24 Available Fault Current.
(A) Field Marking. Service
equipment at other than dwelling
units shall be legibly marked in the
field with the maximum available
fault current. The field marking(s)
shall include the date the faultcurrent calculation was performed
and be of sufficient durability to
withstand the environment
involved. The calculation shall be
documented and made available to
those authorized to design, install,
inspect, maintain, or operate the
system.
2014
2017 (NEW SUBSECTION)
No Section
110.26(A)
(4) Limited Access. Where
equipment operating at 1000
volts, nominal, or less to
ground and likely to require
examination, adjustment,
servicing, or maintenance
while energized is required by
installation instructions or
function to be located in a
space with limited access, all
of the following shall apply:

(a) Where equipment is installed above a lay-in ceiling, there shall be
an opening not smaller than 559 mm × 559 mm (22 in. × 22 in.), or in a
crawl space, there shall be an accessible opening not smaller than 559
mm × 762 mm (22 in. × 30 in.).
(b) The width of the working space shall be the width of the equipment
enclosure or a minimum of 762 mm (30 in.), whichever is greater.
(c) All enclosure doors or hinged panels shall be capable of opening a
minimum of 90 degrees.
(d) The space in front of the enclosure shall comply with the depth
requirements of Table 110.26(A)(1). The maximum height of the
working space shall be the height necessary to install the equipment in
the limited space. A horizontal ceiling structural member or access
panel shall be permitted in this space.
2014
2017
No Section
110.26(A)
(5) Separation from High-Voltage
Equipment. Where switches,
cutouts, or other equipment
operating at 1000 volts, nominal, or
less are installed in a vault, room,
or enclosure where there are
exposed live parts or exposed
wiring operating over 1000 volts,
nominal, the high-voltage
equipment shall be effectively
separated from the space occupied
by the lowvoltage equipment by a
suitable partition, fence, or screen.
2014
2017
No Section
110.41 Inspections and Tests.
(A) Pre-energization and Operating
Tests. Where required elsewhere in this
Code, the complete electrical system
design, including settings for protective,
switching, and control circuits, shall be
prepared in advance and made
available on request to the authority
having jurisdiction and shall be tested
when first installed on-site.
(B) Test Report. A test report covering
the results of the tests required in
110.41(A) shall be available to the
authority having jurisdiction prior to
energization and made available to
those authorized to install, operate, test,
and maintain the system.
2014
2017
200.6(D)(3)
(3) Other and different
means of identification as
allowed by 200.6(A) or (B)
that will distinguish each
system grounded
conductor.
200.6(D)(3)
(3) Other and different
means of identification
allowed by 200.6(A) or (B)
shall distinguish each
system grounded
conductor.
2014
2017
210.1 Scope. This article
covers branch circuits
except for branch circuits
that supply only motor
loads, which are covered in
Article 430. Provisions of
this article and Article 430
apply to branch circuits
with combination loads.
210.1 Scope. This article
provides the general
requirements for branch
circuits.
2014
2017
210.3 Rating. Branch circuits
recognized by this article shall be
rated in accordance with the
maximum permitted ampere
rating or setting of the
overcurrent device. The rating for
other than individual branch
circuits shall be 15, 20, 30, 40, and
50 amperes. Where conductors of
higher ampacity are used for any
reason, the ampere rating or
setting of the specified
overcurrent device shall
determine the circuit rating.
210.3 Other Articles for
Specific-Purpose Branch
Circuits.
Table 210.3 lists references
for specific equipment and
applications not located in
Chapters 5, 6, and 7 that
amend or supplement the
requirements of this article.
2014
2017
(D) Grouping. The
ungrounded and grounded
circuit conductors of each
multiwire branch circuit
shall be grouped by cable
ties or similar means in at
least one location within the
panelboard or other point of
origination.
(D) Grouping. The
ungrounded and grounded
circuit conductors of each
multiwire branch circuit
shall be grouped in
accordance with 200.4(B).
2014
2017
No Exception
210.5(C)(1)(b)
Exception: In existing installations where a
voltage system(s) already exists and a
different voltage system is being added, it
shall be permissible to mark only the new
system voltage. Existing unidentified
systems shall not be required to be identified
at each termination, connection, and splice
point in compliance with 210.5(C)(1)(a) and
(b). Labeling shall be required at each
voltage system distribution equipment to
identify that only one voltage system has
been marked for a new system(s). The new
system label(s) shall include the words
“other unidentified systems exist on the
premises.”
2014
2017
No informational note 2
And no second sentence
Informational Note No. 2: See 422.5(A)
for GFCI requirements
for appliances.
(Second sentence added)
For the purposes of this section, when
determining distance from receptacles
the distance shall be measured as the
shortest path the cord of an appliance
connected to the receptacle would
follow without piercing a floor, wall,
ceiling, or fixed barrier, or passing
through a door, doorway, or window.
2014
2017
(7) Sinks — where
receptacles are installed
within 1.8 m (6 ft) of the
outside edge of the sink
(7) Sinks — where
receptacles are installed
within 1.8 m (6 ft) from the
top inside edge of the bowl
of the sink
2014
2017
(B) Other Than Dwelling
Units. All 125-volt,
singlephase, 15- and 20ampere receptacles installed
in the locations specified in
210.8(B)(1) through (8) shall
have ground fault circuitinterrupter protection for
personnel.
(B) Other Than Dwelling
Units. All single-phase
receptacles rated 150 volts to
ground or less, 50 amperes or
less and three phase
receptacles rated 150 volts to
ground or less, 100 amperes or
less installed in the following
locations shall have groundfault circuit-interrupter
protection for personnel.
(1) Bathrooms
(2) Kitchens
(3) Rooftops
(4) Outdoors
(5) Sinks — where receptacles are installed within 1.8 m (6 ft)
from the top inside edge of the bowl of the sink
(6) Indoor wet locations
(7) Locker rooms with associated showering facilities
(8) Garages, service bays, and similar areas other than vehicle
exhibition halls and showrooms
(9) Crawl spaces — at or below grade level
(10) Unfinished portions or areas of the basement not intended
as habitable rooms
2014

No subsection
2017
210.11(C)(4) Garage Branch
Circuits. In addition to the
number of branch circuits
required by other parts of this
section, at least one 120-volt,
20-ampere branch circuit shall
be installed to supply
receptacle outlets in attached
garages and in detached
garages with electric power.
This circuit shall have no other
outlets.
2014

No subsection
2017
210.12(C) Guest Rooms and
Guest Suites. All 120-volt,
single-phase, 15- and 20ampere branch circuits
supplying outlets and
devices installed in guest
rooms and guest suites of
hotels and motels shall be
protected by any of the
means described in
210.12(A)(1) through (6).
2014

Originally 210.3
2017
Relocated to 210.18
210.18 Rating. Branch circuits
recognized by this article shall be
rated in accordance with the
maximum permitted ampere rating
or setting of the overcurrent device.
The rating for other than individual
branch circuits shall be 15, 20, 30,
40, and 50 amperes. Where
conductors of higher ampacity are
used for any reason, the ampere
rating or setting of the specified
overcurrent device shall determine
the circuit rating.
2014
2017
Exception No. 2: The
receptacle outlet for
refrigeration equipment shall
be permitted to be supplied
from an individual branch
circuit rated 15 amperes or
greater.
Exception No. 2: In addition to
the required receptacles
specified by 210.52, a
receptacle outlet to serve a
specific appliance shall be
permitted to be supplied from
an individual branch circuit
rated 15 amperes or greater.
2014
2017
(3) Peninsular Countertop
Spaces. At least one receptacle
outlet shall be installed at each
peninsular countertop space
with a long dimension of 600
mm (24 in.) or greater and a
short dimension of 300 mm (12
in.) or greater. A peninsular
countertop is measured from
the connecting edge.
(3) Peninsular Countertop
Spaces. At least one receptacle
outlet shall be installed at each
peninsular countertop long
dimension space with a long
dimension of 600 mm (24 in.)
or greater and a short
dimension of 300 mm (12 in.)
or greater. A peninsular
countertop is measured from
the connected perpendicular
wall.
2014
2017
(1) Garages. In each
attached garage and in each
detached garage with
electric power. The branch
circuit supplying this
receptacle(s) shall not
supply outlets outside of the
garage. At least one
receptacle outlet shall be
installed for each car space.
(1) Garages. In each
attached garage and in each
detached garage with
electric power, at least one
receptacle outlet shall be
installed in each vehicle bay
and not more than 1.7 m
(51∕2 ft) above the floor.
2014
2017
210.64 Electrical Service
Areas. At least one 125-volt,
single-phase, 15- or 20ampere-rated receptacle outlet
shall be installed within 15 m
(50 ft) of the electrical service
equipment.
Exception: The receptacle outlet
shall not be required to be
installed in one-and two-family
dwellings.
210.64 Electrical Service Areas. At least one
125-volt, single phase, 15- or 20-ampere-rated
receptacle outlet shall be installed in an
accessible location within 7.5 m (25 ft) of the
indoor electrical service equipment. The
required receptacle outlet shall be located
within the same room or area as the service
equipment.
Exception No. 1: The receptacle outlet shall not be
required to be installed
in one- and two-family dwellings.
Exception No. 2: Where the service voltage is
greater than 120 volts to ground, a receptacle
outlet shall not be required for services dedicated
to equipment covered in Articles 675 and 682.
2014
2017
No Section
210.71 Meeting Rooms.
(A) General. Each meeting room
of not more than 93 m2 (1000 ft2)
in other than dwelling units shall
have outlets for nonlocking-type,
125-volt, 15- or 20-ampere
receptacles. The outlets shall be
installed in accordance with
210.71(B). Where a room or space
is provided with movable
partition(s), each room size shall
be determined with the partition
in the position that results in the
smallest size meeting room.
2014
2017
No Section
(B) Receptacle Outlets
Required. The total number of
receptacle outlets, including
floor outlets and receptacle
outlets in fixed furniture, shall
not be less than as determined
in (1) and (2). These receptacle
outlets shall be permitted to be
located as determined by the
designer or building owner.
2014
2017
No Section
(1) Receptacle Outlets in Fixed
Walls. Receptacle outlets shall be
installed in accordance with
210.52(A)(1) through (A)(4).
(2) Floor Receptacle Outlets. A
meeting room that is at least 3.7 m
(12 ft) wide and that has a floor
area of at least 20 m2 (215 ft2)
shall have at least one receptacle
outlet located in the floor at a
distance not less than 1.8 m (6 ft)
from any fixed wall for each 20
m2 (215 ft2) or major portion of
floor space.
2014
2017
220.3 Application of Other
Articles. In other articles
applying to the calculation
of loads in specialized
applications, there are
requirements provided in
Table 220.3 that are in
addition to, or modifications
of, those within this article.
220.3 Other Articles for
Specific-Purpose
Calculations. Table 220.3
shall provide references for
specific-purpose calculation
requirements not located in
Chapters 5, 6, or 7 that
amend or supplement the
requirements of this article.
2014
2017
No Section
Exception No. 2: Where a building is
designed and constructed to comply
with an energy code adopted by the
local authority and specifying an
overall lighting density of less than
13.5 volt-amperes/13.5 m2 (1.2 voltamperes/1.2 ft2), the unit lighting
loads in Table 220.12 for office and
bank areas within the building shall
be permitted to be reduced by 11 voltamperes/11 m2 (1 volt-amperes/1
ft2).
2014
2017
Exception: If the maximum demand data for a 1year period is not available, the calculated load
shall be permitted to be based on the maximum
demand (measure of average power demand over a
15-minute period) continuously recorded over a
minimum 30-day period using a recording
ammeter or power meter connected to the highest
loaded phase of the feeder or service, based on the
initial loading at the start of the recording. The
recording shall reflect the maximum demand of
the feeder or service by being taken when the
building or space is occupied and shall include by
measurement or calculation the larger of the
heating or cooling equipment load, and other
loads that may be periodic in nature due to
seasonal or similar conditions.
Exception: If the maximum demand data for a 1year period is not available, the calculated load
shall be permitted to be based on the maximum
demand (the highest average kilowatts reached
and maintained for a 15-minute interval)
continuously recorded over a minimum 30-day
period using a recording ammeter or power meter
connected to the highest loaded phase of the feeder
or service, based on the initial loading at the start
of the recording. The recording shall reflect the
maximum demand of the feeder or service by
being taken when the building or space is
occupied and shall include by measurement or
calculation the larger of the heating or cooling
equipment load, and other loads that may be
periodic in nature due to seasonal or similar
conditions.
2014
2017
230.75 Disconnection of Grounded
Conductor. Where the service
disconnecting means does not
disconnect the grounded conductor
from the premises wiring, other means
shall be provided for this purpose in the
service equipment. A terminal or bus to
which all grounded conductors can be
attached by means of pressure
connectors shall be permitted for this
purpose. In a multisection switchboard
or switchgear, disconnects for the
grounded conductor shall be permitted
to be in any section of the switchboard
or switchgear, provided that any such
switchboard or switchgear section is
marked.
230.75 Disconnection of Grounded
Conductor. Where the service disconnecting
means does not disconnect the grounded
conductor from the premises wiring, other
means shall be provided for this purpose in
the service equipment. A terminal or bus to
which all grounded conductors can be
attached by means of pressure connectors
shall be permitted for this purpose. In a
multisection switchboard or switchgear,
disconnects for the grounded conductor shall
be permitted to be in any section of the
switchboard or switchgear, if the
switchboard or switchgear section is marked
to indicate a grounded conductor disconnect
is located within.
2014
2017
230.91 Location. The service
overcurrent device shall be
an integral part of the
service disconnecting means
or shall be located
immediately adjacent
thereto.
230.91 Location. The service
overcurrent device shall be an
integral part of the service
disconnecting means or shall
be located immediately
adjacent thereto. Where fuses
are used as the service
overcurrent device, the
disconnecting means shall be
located ahead of the supply
side of the fuses.
2014
2017
(C) Performance Testing. The
ground-fault protection system
shall be performance tested
when first installed on site.
The test shall be conducted in
accordance with instructions
that shall be provided with the
equipment. A written record
of this test shall be made and
shall be available to the
authority having jurisdiction.
(C) Performance Testing. The
ground-fault protection system
shall be performance tested when
first installed on site. This testing
shall be conducted by a qualified
person(s) using a test process of
primary current injection, in
accordance with instructions that
shall be provided with the
equipment. A written record of
this testing shall be made and
shall be available to the authority
having jurisdiction.
2014
2017
240.6 Standard Ampere Ratings.
(A) Fuses and Fixed-Trip Circuit
Breakers. The standard ampere ratings
for fuses and inverse time circuit
breakers shall be considered 15, 20, 25,
30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110,
125, 150, 175, 200, 225, 250, 300, 350, 400,
450, 500, 600, 700, 800, 1000, 1200, 1600,
2000, 2500, 3000, 4000, 5000, and 6000
amperes. Additional standard ampere
ratings for fuses shall be 1, 3, 6, 10, and
601. The use of fuses and inverse time
circuit breakers with nonstandard
ampere ratings shall be permitted.
240.6 Standard Ampere Ratings.
(A) Fuses and Fixed-Trip Circuit
Breakers. The standard ampere
ratings for fuses and inverse time
circuit breakers shall be
considered as shown in Table
240.6(A). Additional standard
ampere ratings for fuses shall be
1, 3, 6, 10, and 601. The use of
fuses and inverse time circuit
breakers with nonstandard
ampere ratings shall be permitted.
2014
No Section
2017
240.67 Arc Energy Reduction. Where fuses rated 1200 A or
higher are installed, 240.67(A) and (B) shall apply. This
requirement shall become effective January 1, 2020.
(A) Documentation. Documentation shall be available to
those authorized to design, install, operate, or inspect the
installation as to the location of the fuses.
(B) Method to Reduce Clearing Time. A fuse shall have a
clearing time of 0.07 seconds or less at the available arcing
current, or one of the following shall be provided:
(1) Differential relaying
(2) Energy-reducing maintenance switching with local status
Indicator
(3) Energy-reducing active arc flash mitigation system
(4) An approved equivalent means
2014
240.87 Arc Energy Reduction. Where the highest continuous current trip setting for
which the actual overcurrent device installed in a circuit breaker is rated or can be
adjusted is 1200 A or higher, 240.87(A) and (B) shall apply.
(A) Documentation. Documentation shall be available to
those authorized to design, install, operate, or inspect the installation as to the
location of the circuit breaker(s).
(B) Method to Reduce Clearing Time. One of the following or approved equivalent
means shall be provided:
(1) Zone-selective interlocking
(2) Differential relaying ARTICLE 240—OVERCURRENT PROTECTION 240.87
2014
(3) Energy-reducing maintenance switching with local status indicator
(4) Energy-reducing active arc flash mitigation system
(5) An approved equivalent means
2017
240.87 Arc Energy Reduction. Where the highest continuous current trip setting for which the
actual overcurrent device installed in a circuit breaker is rated or can be adjusted is 1200 A or
higher, 240.87(A) and (B) shall apply.
(A) Documentation. Documentation shall be available to
those authorized to design, install, operate, or inspect the
installation as to the location of the circuit breaker(s).
(B) Method to Reduce Clearing Time. One of the following
means shall be provided:
(1) Zone-selective interlocking
(2) Differential relaying
(3) Energy-reducing maintenance switching with local status indicator
(4) Energy-reducing active arc flash mitigation system
(5) An instantaneous trip setting that is less than the available
arcing current
(6) An instantaneous override that is less than the available
arcing current
(7) An approved equivalent means
2014
2017
No Informational Note 2
Informational Note No. 2:
See NFPA 780-2014,
Standard for the Installation of
Lightning Protection Systems,
for information on
installation of grounding
and bonding for lightning
protection systems.
2014
2017
250.22 Circuits Not to Be Grounded.
The following circuits shall not be
grounded:
(1) Circuits for electric cranes operating
over combustible fibers in Class III
locations, as provided in 503.155
(2) Circuits in health care facilities as
provided in 517.61 and 517.160
(3) Circuits for equipment within
electrolytic cell working zone as
provided in Article 668
(4) Secondary circuits of lighting
systems as provided in 411.6(A)
(5) Secondary circuits of lighting
systems as provided in 680.23(A)(2).
250.22 Circuits Not to Be Grounded. The
following circuits shall not be grounded:
(1) Circuits for electric cranes operating over
combustible fibers in Class III locations, as
provided in 503.155
(2) Circuits in health care facilities as
provided in 517.61 and 517.160
(3) Circuits for equipment within electrolytic
cell line working zones as provided in Article
668
(4) Secondary circuits of lighting systems as
provided in 411.6(A)
(5) Secondary circuits of lighting systems as
provided in 680.23(A)(2)
(6) Class 2 load side circuits for suspended
ceiling low-voltage power grid distribution
systems as provided in 393.60(B)
2014
2017
(4) Grounding Electrode. The
grounding electrode shall be as
near as practicable to, and
preferably in the same area as, the
grounding electrode conductor
connection to the system. The
grounding electrode shall be the
nearest of one of the following:
(1) Metal water pipe grounding
electrode as specified in
250.52(A)(1)
(2) Structural metal grounding
electrode as specified in
250.52(A)(2)
(4) Grounding Electrode.
The building or structure
grounding electrode system
shall be used as the
grounding electrode for the
separately derived system.
If located outdoors, the
grounding electrode shall be
in accordance with
250.30(C) .
2014
2017
(a) Common Grounding Electrode
Conductor. The common grounding
electrode conductor shall be permitted
to be one of the following:
(1) A conductor of the wire type not
smaller than 3/0 AWG copper or 250
kcmil aluminum
(2) The metal frame of the building or
structure that complies with
250.52(A)(2) or is connected to the
grounding electrode system by a
conductor that shall not be smaller than
3/0 AWG copper or 250 kcmil
aluminum
(no number 3)
(a) Common Grounding Electrode
Conductor. The common grounding
electrode conductor shall be permitted
to be one of the following:
(1) A conductor of the wire type not
smaller than 3/0 AWG copper or 250
kcmil aluminum
(2) A metal water pipe that complies
with 250.68(C)(1)
(3) The metal structural frame of the
building or structure that complies with
250.68(C)(2) or is connected to the
grounding electrode system by a
conductor not smaller than 3/0 AWG
copper or 250 kcmil aluminum
2014
2017
(2) Listed connections to
aluminum or copper
busbars not smaller than 6
mm × 50mm (1∕4 in. × 2 in.).
If aluminum busbars are
used, the installation shall
comply with 250.64(A).
(2) Listed connections to
aluminum or copper busbars
not smaller than 6 mm thick ×
50 mm wide (1∕4 in. thick × 2
in. wide) and of sufficient
length to accommodate the
number of terminations
necessary for the installation. If
aluminum busbars are used,
the installation shall also
comply with 250.64(A).
2014
2017
(2) Metal Frame of the Building or Structure. The metal
frame of the building or structure that is connected to the
earth by one or more of the following methods:
(1) At least one structural metal member that is in direct
contact with the earth for 3.0 m (10 ft) or more, with or
without concrete encasement.
(2) Hold-down bolts securing the structural steel column
that are connected to a concrete-encased electrode that
complies with 250.52(A)(3) and is located in the support
footing or foundation. The hold-down bolts shall be
connected to the concrete-encased electrode by
welding, exothermic welding, the usual steel tie wires,
or other approved means.
(2) Metal In-ground Support
Structure(s). One or more
metal in-ground support
structure(s) in direct contact
with the earth vertically for 3.0
m (10 ft) or more, with or
without concrete encasement.
If multiple metal in-ground
support structures are present
at a building or a structure, it
shall be permissible to bond
only one into the grounding
electrode system.
2014
2017
(B) Not Permitted for Use
as Grounding Electrodes.
The following systems and
materials shall not be used
as grounding electrodes:
(1) Metal underground gas
piping systems
(2) Aluminum
(B) Not Permitted for Use as
Grounding Electrodes. The
following systems and
materials shall not be used as
grounding electrodes:
(1) Metal underground gas
piping systems
(2) Aluminum
(3) The structures and
structural reinforcing steel
described in 680.26(B)(1) and
(B)(2) (pools)
2014
2017
(C) Connections to Ground
Rings. Where the grounding
electrode conductor is
connected to a ground ring as
permitted in 250.52(A)(4), that
portion of the conductor that is
the sole connection to the
grounding electrode shall not
be required to be larger than
the conductor used for the
ground ring.
(C) Connections to Ground
Rings. If the grounding
electrode conductor or
bonding jumper connected to a
ground ring, as described in
250.52(A)(4), does not extend
on to other types of electrodes
that require a larger size of
conductor, the grounding
electrode conductor shall not
be required to be larger than
the conductor used for the
ground ring.
2014
2017
(1) Interior metal water
piping located not more
than 1.52 m (5 ft) from the
point of entrance to the
building shall be permitted
to be used as a conductor to
interconnect electrodes that
are part of the grounding
electrode system.
(1) Interior metal water piping
that is electrically continuous
with a metal underground water
pipe electrode and is located not
more than 1.52 m (5 ft) from the
point of entrance to the building
shall be permitted to extend the
connection to an electrode(s).
Interior metal water piping
located more than 1.52 m (5 ft)
from the point of entrance to the
building shall not be used as a
conductor to interconnect
electrodes of the grounding
electrode system.
2014

No Subsection
2017
(B) Other Means. Connections to
an aluminum or copper busbar
not less than 6 mm thick × 50 mm
wide (1∕4 in. thick × 2 in. wide)
and of sufficient length to
accommodate at least three
terminations for communication
systems in addition to other
connections. The busbar shall be
securely fastened and shall be
installed in an accessible location.
Connections shall be made by a
listed connector. If aluminum
busbars are used, the installation
shall also comply with 250.64(A).
2014
2017
(F) Conductors in Parallel. Where
conductors are installed in parallel in
multiple raceways or cables as permitted in
310.10(H), the equipment grounding
conductors, where used, shall be installed in
parallel in each raceway or cable. Where
conductors are installed in parallel in the
same raceway, cable, or cable tray as
permitted in 310.10(H), a single equipment
grounding conductor shall be permitted.
Equipment grounding conductors installed in
cable tray shall meet the minimum
requirements of 392.10(B)(1)(c).
(F) Conductors in Parallel.
For circuits of parallel
conductors as permitted in
310.10(H), the equipment
grounding conductor shall
be installed in accordance
with (1) or (2).
Each equipment grounding conductor shall
be sized in compliance with 250.122.
(1) Conductor Installations in Raceways, Auxiliary Gutters, or
Cable Trays.
(a) Single Raceway or Cable Tray. If conductors are installed in parallel in the
same raceway or cable tray, a single wiretype conductor shall be permitted as
the equipment grounding conductor. The wire-type equipment grounding
conductor shall be sized in accordance with 250.122, based on the overcurrent
protective device for the feeder or branch circuit. Wiretype equipment
grounding conductors installed in cable trays shall meet the minimum
requirements of 392.10(B)(1)(c). Metal raceways or auxiliary gutters in
accordance with 250.118 or cable trays complying with 392.60(B) shall be
permitted as
the equipment grounding conductor.
(b) Multiple Raceways. If conductors are installed in parallel in multiple
raceways, wire-type equipment grounding conductors, where used, shall be
installed in parallel in each raceway. The equipment grounding conductor
installed in each raceway shall be sized in compliance with 250.122 based on
the overcurrent protective device for the feeder or branch circuit. Metal
raceways or auxiliary gutters in accordance with 250.118 or cable trays
complying with 392.60(B) shall be permitted as the equipment grounding
(2) Multiconductor Cables.
(a) If multiconductor cables are installed in parallel, the equipment
grounding conductor(s) in each cable shall be connected in parallel.
(b) If multiconductor cables are installed in parallel in the same
raceway, auxiliary gutter, or cable tray, a single equipment grounding
conductor that is sized in accordance with 250.122 shall be permitted
in combination with the equipment grounding conductors provided
within the multiconductor cables and shall all be connected together.
(c) Equipment grounding conductors installed in cable trays shall meet
the minimum requirements of 392.10(B)(1)(c). Cable trays complying
with 392.60(B), metal raceways in accordance with 250.118, or
auxiliary gutters shall be permitted as the equipment grounding
conductor.
(d) Except as provided in 250.122(F)(2)(b) for raceway or cable tray
installations, the equipment grounding conductor in each
multiconductor cable shall be sized in accordance with 250.122 based
on the overcurrent protective device for the feeder or branch circuit.
2014
2017
(c) Raceways and Cables Exposed
to Sunlight on Rooftops. Where
raceways or cables are exposed
to direct sunlight on or above
rooftops, the adjustments
shown in Table 310.15(B)(3)(c)
shall be added to the outdoor
temperature to determine the
applicable ambient
temperature for application of
the correction factors in Table
310.15(B)(2)(a) or Table
310.15(B)(2)(b).
(c) Raceways and Cables Exposed to
Sunlight on Rooftops. Where raceways or
cables are exposed to direct sunlight on
or above rooftops, raceways or cables
shall be installed a minimum distance
above the roof to the bottom of the
raceway or cable of 23 mm (7∕8 in.).
Where the distance above the roof to the
bottom of the raceway is less than 23
mm (7∕8 in.), a temperature adder of
33°C (60°F) shall be added to the
outdoor temperature to determine the
applicable ambient temperature for
application of the correction factors in
Table 310.15(B)(2)(a) or Table
310.15(B)(2)(b).
2014
2017
No Subsection
(E) Separable Attachment
Fittings. Outlet boxes required in
314.27 shall be permitted to
support listed locking support
and mounting receptacles used in
combination with compatible
attachment fittings. The
combination shall be identified
for the support of equipment
within the weight and mounting
orientation limits of the listing.
Where the supporting receptacle
is installed within a box, it shall
be included in the fill calculation
covered in 314.16(B)(4).
2014
2017
No Section
328.30 Support. Type MV cable
terminated in equipment or
installed in pull boxes or vaults
shall be secured and supported
by metallic or nonmetallic
supports suitable to withstand the
weight by cable ties listed and
identified for securement and
support, or other approved
means, at intervals not exceeding
1.5 m (5 ft) from terminations or a
maximum of 1.8 m (6 ft) between
supports.
2014
2017
No Section
366.20 Conductors Connected in
Parallel. Where single conductor
cables comprising each phase,
neutral, or grounded conductor of
an alternating-current circuit are
connected in parallel as permitted
in 310.10(H), the conductors shall
be installed in groups consisting
of not more than one conductor
per phase, neutral, or grounded
conductor to prevent current
imbalance in the paralleled
conductors due to inductive
reactance.
2014
2017
No Subsection
(4) Where an instantaneous trip
circuit breaker or semiconductor
fuses are permitted in accordance
with the drive manufacturer’s
instructions for use as the branchcircuit short-circuit and groundfault protective device for listed
power conversion equipment,
they shall be provided as an
integral part of a single listed
assembly incorporating both the
protective device and power
conversion equipment.
2014
2017
No Section
440.9 Grounding and
Bonding. Where multimotor
and combination-load
equipment is installed
outdoors on a roof, an
equipment grounding
conductor of the wire type
shall be installed in outdoor
portions of metallic raceway
systems that use non-threaded
fittings.
2014
445.18 Disconnecting Means Required for Generators.
Generators shall be equipped with a disconnect(s), lockable in
the open position by means of which the generator and all
protective devices and control apparatus are able to be
disconnected entirely from the circuits supplied by the generator
except where the following conditions apply:
(1) Portable generators are cord- and plug-connected, or
(2) Both of the following conditions apply:
a. The driving means for the generator can be readily shut down,
is rendered incapable of restarting, and is lockable in the OFF
position in accordance with 110.25.
b. The generator is not arranged to operate in parallel with
another generator or other source of voltage.
2017
445.18 Disconnecting Means and Shutdown of Prime Mover.
(A) Disconnecting Means. Generators other than cord-andplug- connected
portable shall have one or more disconnecting means. Each disconnecting
means shall simultaneously open all associated ungrounded conductors.
Each disconnecting means shall be lockable in the open position in
accordance with 110.25.
(B) Shutdown of Prime Mover. Generators shall have provisions to shut
down the prime mover. The means of shutdown shall comply with all of
the following:
(1) Be equipped with provisions to disable all prime mover start control
circuits to render the prime mover incapable of starting
(2) Initiate a shutdown mechanism that requires a mechanical reset The
provisions to shut down the prime mover shall be permitted to satisfy the
requirements of 445.18(A) where it is capable of being locked in the open
position in accordance with 110.25. Generators with greater than 15 kW
rating shall be provided with an additional requirement to shut down the
prime mover. This additional shutdown means shall be located outside the
equipment room or generator enclosure and shall also meet the
requirements of 445.18(B)(1) and (B)(2).