CODECOMMENTS BY MICHAEL JOHNSTON
Multiple definitions of words and terms
pertaining to hazardous (classified) locations previously located in 500.2 have
been relocated to Article 100. The words
“as applied to Hazardous (Classified)
Locations” have been added in brackets
following each relocated term.
Article 100—Readily Accessible
The definition of “readily accessible”
has been revised. The definition maintains most of its existing text and now
includes “other than keys.” A new informational note addresses the common
practice and use of keys in gaining accessibility under controlled conditions.
Article 100—Field Evaluation
Body and Field Labeled
New definitions of “field evaluation
body” and “field labeled” have been
incorporated into Article 100. These
definitions have been developed from
concepts derived from terms in NFPA
790, Standard for Competency of Third-Party Field Evaluation Bodies.
The definition of “structure” has been
revised by adding “other than equipment.”
The revision provides a clear differentiation between what constitutes electrical
equipment as compared to structures.
The title of Part II of Article 100 has been
changed from “Over 600 Volts, Nominal”
to “Over 1000 Volts, Nominal.” The previous definition of “Substation” has been
relocated from Part I to Part II.
The definition has been revised to
clarify its physical characteristics and
how it is usually intended to perform. A
substation is defined as an assemblage
of equipment (e.g., switches, interrupt-
ing devices, circuit breakers, buses and
transformers) through which electri-
cal energy is passed for the purpose of
distribution, switching or modifying its
characteristics. A substation can be an
outdoor substation in an enclosure such
as a fence, or it can be a unit substation.
Article 110—Requirements for
110. 3(A) Examination
A new informational note No. 1 has been
added to 110. 3(A)( 1). Previous Informational Note No. 1 has been renumbered
as Informational Note No. 2. The new
note clarifies that the term “equipment”
used in this section can apply to new,
reconditioned, refurbished or remanufactured equipment.
110. 3(C) Listing
The title of 110. 3 has been revised to
include the words “(product certification).” A new Subdivision (C) and
associated informational note have been
added to Section 110. 3.
The revision clarifies that listing (product certification) must be
performed by recognized, qualified electrical testing laboratories, and the new
informational note indicates that the
Occupational Safety and Health Administration (OSHA) provides a list of such
110. 14(D) Installation
A new subdivision (D), “Installation,”
has been added following 110. 14(C).
This subdivision incorporates manda-
tory torque tightening requirements for
electrical terminations in accordance
with the manufacturer’s instructions.
It also allows for alternative methods as
provided in the instructions. The infor-
mational note to 110. 14 has been deleted
because it is no longer necessary.
110. 16(B) Service Equipment
A new (B), “Service Equipment,” and
informational note have been added
to 110. 16. The provisions in 110. 16 now
require more installation-related detail
and information for determining arc-flash energy levels and required PPE.
The nominal system voltage, available
fault current, the service overcurrent
protective device clearing time, and the
label date must now be included in the
arc-flash warning label. The informational note references NFPA 70E for
specific criteria related to arc-flash labels
and determining appropriate PPE.
110. 21(A) Equipment Markings
The title of subdivision (A) has been
changed to “Equipment Markings”
from “Manufacturer’s Markings.” Section 110. 21(A) has been renumbered
as list items ( 1) and a new list item ( 2)
with a new exception and informational
note. New list item ( 2) provides marking requirements for reconditioned
equipment including the responsible
organization and date of reconditioning.
110. 24(A) Field Marking
A new last sentence has been added to
110. 24(A) addressing calculations. The
additional requirements are intended to
document the calculation and make it avail-
able to those authorized to design, install,
inspect, maintain or operate the system.
The maximum level of available fault cur-
rent can be obtained from published utility
data or by use of calculation methods.
http://goo.gl/U3vLo7 to view all
of the proposed revisions.
Definitions and Requirements
Significant changes in the 2017 NEC, part 2
THIS ARTICLE IS PART 2 IN A SERIES that examines some of the more significant
revisions and new requirements in the 2017 National Electrical Code (NEC). This
piece reviews some significant changes in Articles 100 and 110.
JOHNS TON is NECA’s executive director of standards and safety. He is chair of the NEC
Technical Correlating Committee; member of the IBEW; and an active member of the NFPA
Electrical Section, Education Section and the UL Electrical Council. Reach him at