The document discusses requirements for various types of wiring methods and raceways. It covers corrosion protection for ferrous metal equipment, acceptable wiring methods for spaces used for environmental air like plenums, raceway installation in wet locations above grade, construction requirements for rigid metal conduit, couplings and connectors for liquidtight flexible metal conduit, grounding requirements for liquidtight flexible nonmetallic conduit, and marking requirements for surface nonmetallic raceways.

1. 300.6 Protection Against
Corrosion and Deterioration
 (A) Ferrous Metal Equipment.
… Where corrosion protection is necessary and
the conduit is threaded in the field, the threads
shall be coated with an approved electrically
conductive, corrosion-resistant compound.
 Informational Note: Field-cut threads are those
threads that are cut in conduit, elbows, or
nipples anywhere other than at the factory
where the product is listed.

2. 300.22 Wiring in Ducts Not Used for Air
Handling, Fabricated Ducts for
Environmental Air, and Other Spaces for
Environmental Air (Plenums)
 (C) Other Spaces Used for Environmental Air (Plenums).
(1) Wiring Methods.
 The wiring methods for such other space shall be limited to
totally enclosed, non-ventilated, insulated busway having no
provisions for plug-in connections, Type MI cable without an
overall nonmetallic covering, Type MC cable without an overall
nonmetallic covering, Type AC cable, or other factory-assembled
multi-conductor control or power cable that is specifically listed
for use within an air-handling space, or listed prefabricated cable
assemblies of metallic manufactured wiring systems without
nonmetallic sheath.

3. 300.22(C)(1) – (cont.)
 Other types of cables, conductors, and raceways
shall be permitted to be installed in electrical
metallic tubing, flexible metallic tubing,
intermediate metal conduit, rigid metal conduit
without an overall nonmetallic covering, flexible
metal conduit, or, where accessible, surface
metal raceway or metal wireway with metal
covers.

4. 300.22(C)(1) – (cont.)
 Nonmetallic cable ties and other nonmetallic cable accessories
used to secure and support cables shall be listed as having low
smoke and heat release properties.
 Informational Note: One method to determine low smoke and
heat release properties is that the nonmetallic cable ties and other
nonmetallic cable accessories exhibit a maximum peak optical
density of 0.50 or less, an average optical density of 0.15 or less,
and a peak heat release rate of 100 kW or less when tested in
accordance with ANSI/UL 2043-2008, Fire Test for Heat and
Visible Smoke Release for Discrete Products and Their Accessories
Installed in Air-Handling Spaces.

5. 300.38 Raceways in Wet
Locations Above Grade
 Where raceways are installed in wet locations
above grade, the interior of these raceways shall
be considered to be a wet location. Insulated
conductors and cables installed in raceways in
wet locations above grade shall comply with
310.10(C).

6. Rigid Metal Conduit: Type RMC
 344.100 Construction
RMC shall be made of one of the following:
(1) Steel (ferrous ), with or without protective
coatings
(2) Aluminum (nonferrous)
(3) Red brass
(4) Stainless steel

7. Liquidtight Flexible Metal
Conduit: Type LFMC
 350.42 Couplings and
Connectors
Only fittings listed for use
with LFMC shall be used.
Angle connectors shall not
be concealed. Straight
LFMC fittings shall be
permitted for direct burial
where marked.

8. Liquidtight Flexible Nonmetallic
Conduit: Type LFNC
 356.60 Grounding
Where equipment grounding is required, a separate
equipment grounding conductor shall be installed
in the conduit.
Exception No. 1: As permitted in 250.134(B), Exception No. 2,
for dc circuits and 250.134(B), Exception No. 1, for separately run
equipment grounding conductors.
Exception No. 2: Where the grounded conductor is used to
ground equipment as permitted in 250.142.

9. Surface Nonmetallic Raceways
 388.120 Marking
Surface nonmetallic raceways that have limited
smoke producing characteristics shall be permitted
to be so identified. Each length of surface
nonmetallic raceway shall be clearly and durably
identified as required in the first sentence of
110.21(A).
 ( 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.