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What the 2011 NEC says
about datacom cable and raceways
in Chapters 1 through 7 that are specifically referenced in Chapter 8 are
The product types are organized into
applicable to Chapter 8. One exam-
a hierarchy of fire safety.
ple is that the cable-tray fill requirements in Article 392 (Cable Trays) do
not apply to installations of communi-
By Stanley Kaufman, CableSafe Inc.
cations (telephone) cables (Type CMP,
The National Electrical Code (NEC)
Examples of articles within Chapter
CMR and CM) covered by Chapter
is published by the National Fire
8 that are important to the data-com-
8. They do not apply to installations
Protection Association (NFPA; www.
munications industry are Article 800,
of data cables (Class 2 cables, Types
nfpa.org) with revisions on a three-
Communications Circuits
year schedule. The 2011 NEC, which
and Article 770, Optical Fiber
replaces the 2008 NEC, was released
Cables and Raceways.
by the NFPA in August 2010. There
tion. The NEC covers com-
ufacturers, installers and users of com-
munications equipment,
munications cable and connectivity
wires and cables installed
products.
in most buildings. It also
and raceways. It exempts
write on behalf of the Communications
communications equipment
Cable and Connectivity Association
installations in telephone-
(CCCA; www.cccassoc.org). This arti-
company central offices
cle’s objective is to provide a basic
where the installation is
understanding of how the NEC is orga-
under the exclusive control
nized, including some of the key terms,
of a communications utility;
definitions and fire-safety relationships
however, it does not exempt
It is intended to serve as a foundation
for the ensuing eight planned articles.
Chapters and Articles. The NEC
is organized into nine chapters. For
example, one chapter is titled “Chapter
Riser cable
OFNR, OFCR, CMR, CATVR, CL2R, CL3R, FPLR
includes optical-fiber cables
to be a series of nine articles that I will
that apply to communications cables.
Plenum cable
OFNP, OFCP, CMP, CATVP, CL2P CL3P, FPLP
Scope and organiza-
were many changes of interest to man-
This is the first in what is planned
Datacam cable fire-safety hierarchy
General purpose cable
OFN, OFC, CM, CMG, CATV, CL2, CL3, FPL
Limited use cable
CMX, CATVX, CL2X, CL3X
In addition to the vertical hierarchy of fire-safety
performance for datacom cables illustrated here,
communications equipment 1107CIMdesignF1
the NEC also allows a horizontal-substitution
in a telephone switching
hierarchy within which communications cables
office run by a nonutility such are permitted to substitute for other cables.
as a large university or nonutility provider of telephone service.
Significantly, the communications
CL2P, CL2R and CL2) because these
cables are in Article 725.
8, Communications Systems.” The
chapter (Chapter 8) of the NEC is inde-
nine chapters of the NEC are divided
pendent of the rest of the code. Only
Data-communications cables
into subsections called Articles.
those electrical wiring requirements
Although widely used in the industry,
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the term “datacom” does not appear in
and fire-alarm cables, and also as a
rigid nonmetallic conduit, intermedi-
the NEC. The term datacom cable, as
substitute for all coaxial CATV cables.
ate metal conduit, liquidtight flexible
we will use it in this article and future
For fire safety, type CMP is the univer-
conduit, flexible metallic tubing, flex-
articles, encompasses six families of
sally acceptable metallic conductor
ible metal conduit, electrical nonme-
cable types in the NEC.
datacom cable.
tallic tubing, electrical metallic tubing,
• Optical fiber cables, Types OFNP,
Optical-fiber cables are available
underfloor raceways, cellular concrete
OFCP, OFNR, OFCR, OFN and OFC
in nonconductive (all-dielectric) and
floor raceways, cellular metal floor race-
•Balanced twisted-pair copper com-
conductive (with a metallic strength
ways, surface raceways, wireways, and
member or metal armor) versions.
busways.
munications cables, Types CMP,
CMR, CMG and CM
• Coaxial cable-TV cables, Types
CATVP, CATVR and CATV
The key words in the definition of a
Datacom raceway fire-safety
hierarchy
• Class 2 cables, Types CL2P, CL2R
Plenum cable
• Class 3 cables, Types CL3P, CL3R
and CL3
section.” Raceways with circular cross
Riser raceway
Types FPLP, FPLR and FPL
“electrical duct” without definition;
General purpose raceway
performance of datacom cables is
levels—Type CMX for example—have
sections are conduits.
The NEC uses the terms “duct” or
Datacom cable fire-safety hier-
hierarchy has four levels, the lowest
nition; most of these definitions include
the words “a raceway or circular cross
• Power-limited fire-alarm cables,
illustrated on page 7. Although the
The NEC does not define conduit,
but each individual conduit has a defi-
and CL2
archy. The hierarchy of fire-safety
raceway are “enclosed channel.”
they are raceways.
The 2011 NEC defines optical-fiber
Like cables, raceways used for data
communications have a fire-safety
1107CIMdesignF2
hierarchy in the NEC that spans from
plenum to general purpose.
restricted uses (one- and two-family
and communications raceways. They
are specialized nonmetallic raceways,
and their definitions are below.
Optical Fiber Raceway. An enclosed
residences), so we will not consider
Nonconductive optical-fiber cables are
channel of nonmetallic materi-
them to be datacom cables. Besides
permitted to substitute for conduc-
als designed for holding optical fiber
the vertical fire-safety hierarchy, there
tive optical-fiber cables at the same
cables in plenum, riser, and general-
is a horizontal substitution hierarchy,
or lower levels on the hierarchy scale.
purpose applications.
with communications cables permit-
Type OFNP is the universal optical-
ted to be substituted for other cables.
fiber cable.
enclosed channel of nonmetallic mate-
nications cable is permitted to sub-
Data-communications raceways
tions wires and cables in plenum, riser,
stitute for Type CL2 and CL3, Class
Various terms including raceway, duct,
and general-purpose applications.
2 and Class 3 general-purpose cables
conduit and innerduct are used to
and Type FPL power-limited fire-alarm
describe pipe-like structures in which
fiber raceways to be installed inside of
cable. Coaxial Type CM is permitted
cables are installed. The 2011 NEC
other raceways as innerduct. Although
to substitute for Type CATV. (All the
defines a raceway as follows. Raceway.
innerduct is not yet defined in the
CATV cables are coaxial.)
An enclosed channel of metal or non-
NEC, it is clear that innerduct is a race-
Type CM general-purpose commu-
Communications Raceway. An
rials designed for holding communica-
The 2011 NEC permits optical-
Combining the vertical hierarchy
metallic materials designed expressly
way that is installed inside of another
and the horizontal cable substitutions,
for holding wires, cables, or busbars,
raceway. Unfortunately, optical-fiber
Type CMP plenum communications
with additional functions as permit-
and communications raceways are
cable is permitted as a substitute for
ted in this Code. Raceways include, but
often referred to as “innerduct” even
all communications, Class 2, Class 3
are not limited to, rigid metal conduit,
if they are not installed inside another
8
July 2011 Cabling Installation & Maintenance
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or certify any information set forth in
accuracy, completeness, efficacy and
this article, nor does it guarantee the
timeliness, and based on the individual
datacom raceways: signaling (Article
accuracy, completeness, efficacy, time-
facts and circumstances of a user.
725), optical fiber (Article 770) and
liness or correct sequencing of such
communications (Article 800). Each is
information. Use of this article and the
Stanley Kaufman, Ph.D. is principal of
available in plenum, riser and general-
views expressed in it is voluntary, and
CableSafe Inc. and a consultant to the
purpose grades, with the same hierar-
reliance on it should only be under-
Communications Cable and Connectivity
chy as the cables.
taken after an independent review of its
Association (CCCA; www.cccassoc.org).
The NEC addresses three kinds of
Enforcement and interpretation
The NEC is intended to be adopted
as law by governments, typically cities, counties and states. Because it is
enforceable by law, it can affect matters such as occupancy certificates
and legal liability in the event of noncompliance. Interpretation of the Code
is the responsibility of the authority
having jurisdiction, which is usually an
electrical inspector.
You now should have a fundamental understanding of some of the
key terms and concepts that apply to
communications cables, and will be
described in further detail in future
articles.
Author’s disclaimer: This article, written on behalf of the
Communications Cable and
Connectivity Association (CCCA), is
offered for general information and
educational purposes. It is not offered,
intended, nor should it be relied upon
as legal advice. The article does not
set forth the views of any member of
any other party, nor may it be taken
as such. CCCA makes no warranty
regarding the accuracy of the information provided in this article, and
expressly disclaims any implied warranties and any liability for use of the
article or reliance on views expressed
in it. CCCA does not endorse, approve
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