Chapter 3 Wiring Methods and Materials

310.12 ARTICLE 310 - CONDUCTORS FOR GENERAL WIRING
(1) The maximum rated voltage.
(2) The proper type letter or letters for the type of wire or
cable as specified elsewhere in this Code.
(3) The manufacturer's name, trademark, or other distinctive
marking by which the organization responsible for
the product can be readily identified.
(4) The AWG size or circular mil area.
FPN: See Conductor Properties, Table 8 of Chapter 9, for
conductor area expressed in SI units for conductor sizes
specified in AWG or circular mil area.
(5) Cable assemblies where the neutral conductor IS
smaller than the ungrounded conductors shall be so
marked.
(B) Method of Marking.
(1) Surface Marking. The following conductors and
cables shall be durably marked on the surface. The AWG
size or circular mil area shall be repeated at intervals not
exceeding 610 mm (24 in.). All other markings shall be
repeated at intervals not exceeding 1.0 m (40 in.).
(1) Single-conductor and multiconductor rubber- and
thermoplastic-insulated wire and cable
(2) Nonmetallic-sheathed cable
(3) Service-entrance cable
(4) Underground feeder and branch-circuit cable
(5) Tray cable
(6) Irrigation cable
(7) Power-limited tray cable
(8) Instrumentation tray cable
(2) Marker Tape. Metal-covered multiconductor cables
shall employ a marker tape located within the cable and
running for its complete length.
Exception No.1: Mineral-insulated. metal-sheathed cable.
Exception No.2: Type AC cable.
Exception No.3: The information required in 31O.11(A)
shall be permitted to be durably marked on the outer nonmetallic
covering of Type MC, Type lTC, or Type PLTC
cables at intervals not exceeding 1.0 m (40 in.).
Exception No.4: The information required in 310.11(A)
shall be permitted to be durably marked on a nonmetallic
covering under the metallic sheath qf Type ITC or Type
PLTC cable at intervals not exceeding 1.0 m (40 in.).
FPN: Included in the group of metal-covered cables are
Type AC cable (Article 320). Type MC cable (Article 330),
and lead-sheathed cable.
(3) Tag Marking. The following conductors and cables
shall be marked by means of a printed tag attached to the
coil, reel, or carton:
(1) Mineral-insulated, metal-sheathed cable
(2) Switchboard wires
(3) Metal-covered, single-conductor cables
(4) Type AC cable
(4) Optional Marking of Wire Size. The information required
in 310. 11 (A)(4) shall be permitted to be marked on
the surface of the individual insulated conductors for the
following multiconductor cables:
(1) Type MC cable
(2) Tray cable
(3) Irrigation cable
(4) Power-limited tray cable
(5) Power-limited fire alarm cable
(6) Instrumentation tray cable
(C) Suffixes to Designate Number of Conductors. A type
letter or letters used alone shall indicate a single insulated
conductor. The letter suffixes shall be indicated as follows:
(1) D - For two insulated conductors laid parallel within
an outer nonmetallic covering
(2) M - For an assembly of two or more insulated conductors
twisted spirally within an outer nonmetallic
covering
(D) Optional Markings. All conductors and cables contained
in Chapter 3 shall be permitted to be surface marked
to indicate special characteristics of the cable materials.
These markings include, but are not limited to, markings
for limited smoke, sunlight resistant, and so forth.
310.12 Conductor Identification.
(A) Grounded Conductors. Insulated or covered grounded
conductors shall be identified in accordance with 200.6.
(B) Equipment Grounding Conductors. Equipment
grounding conductors shall be in accordance with 250.119.
(C) Ungrounded Conductors. Conductors that are intended
for use as ungrounded conductors, whether used as a
single conductor or in multiconductor cables, shall be finished
to be clearly distinguishable from grounded and
grounding conductors. Distinguishing markings shall not
conflict in any manner with the surface markings required
by 31O.11(B)(1). Branch-circuit ungrounded conductors
shall be identified in accordance with 21O.5(C). Feeders
shall be identified in accordance with 215.12.
Exception: Conductor identification shall be permitted in
accordance with 200.7.
310.13 Conductor Constructions and Applications. Insulated
conductors shall comply with the applicable provisions
of Table 310. 13(A) thrl:>ul1rb"1rab:le~~10~13(E).
7()-140 NATIONAL ELECTRICAL CODE 2008 Edition