Cooper Bussmann CT02MAN - Manual (Page 18)

501-4(A)(1)(d) allows Type ITC-HL cable to be
installed in Class I, Division I areas if they have a
gas/vapor tight continuous corrugated aluminum
sheath with a suitable plastic jacket over the sheath
and provided with termination fittings listed for the
application.
501.4. Wiring Methods. (B) Class I, Division 2
(Gases or Vapors). Types ITC, PLTC, MI, MC, MV,
or TC cables may be installed in cable tray in this
type of hazardous (classified) area. Under the
conditions specified in Section 501.5(E), Cable seals
are required in Class 1, Division 2 areas. Cable seals
should be used only when absolutely necessary.
501.5. Sealing and Drainage. (E) Cable Seals,
Class 1, Division 2. (1) Cables will be required to be
sealed only where they enter certain types of
enclosures used in Class 1, Division 2 areas. Factory
sealed push buttons are an example of enclosures
that do not require a cable seal at the entrance of
the cable into the enclosure.
501.5. Sealing and Drainage. (E) Cable Seals,
Class 1, Division 2. (2) Gas blocked cables are
available from some cable manufacturers but they
have not been widely used. For gas to pass through
the jacketed multiconductor cable's core, a pressure
differential must be maintained from one end of the
cable to the other end or to the point where there is
a break in the cable's jacket. The existence of such a
condition is extremely rare and would require that
one end of the cable be in a pressure vessel or a
pressurized enclosure and the other end be exposed
to the atmosphere. The migration of any significant
volume of gas or vapor though the core of a
multiconductor cable is very remote. This is one of
the safety advantages that cable tray wiring systems
have over conduit wiring systems. There are
documented cases of industrial explosions caused by
the migration of gases and vapors through conduits
when they came in contact with an ignition source.
There are no known cases of cables in cable tray
wiring systems providing a path for gases or vapors
to an ignition source which produced an industrial
explosion.
501.5. Sealing and Drainage. (E) Cable Seals,
Class 1, Division 2. (3)
Exception: Cables with an unbroken gas/vapor-
tight continuous sheath shall be permitted to pass
through a Class 1, Division 2 location without
seals.
This is an extremely important exception stating
that cable seals are not required when a cable goes
from an unclassified area through a classified area
then back to an unclassified area.
501.5. Sealing and Drainage. (E) Cable Seals,
Class 1, Division 2. (4)
If you do not have a gas/vapor-tight continuous
sheath, cable seals are required at the boundary of
the Division 2 and unclassified location.
The sheaths mentioned above may be fabricated
of metal or a nonmetallic material.
502.4. Wiring Methods. (A) Class II, Division 1
(Combustible Dusts). Type MI cable may be
installed in cable tray in this type of hazardous
(classified) area.
The Exception allows Type MC cables to be
installed in Class II, Division 1 areas if they have a
gas/vapor tight continuous corrugated aluminum
sheath with a suitable plastic jacket over the sheath.
They must also contain equipment grounding
conductors sized as per Section 250.122 and listed
termination fittings must be used where the cables
enter equipment.
502.4. Wiring Methods. (B) Class II, Division 2
(Combustible Dusts).
This section states:
Type ITC and PLTC cables may be installed in
ladder or ventilated cable trays following the same
practices as used in non-hazardous (unclassified)
areas. No spacing is required between the ITC or
PLTC cables. This is logical as the ITC and PLTC
cable circuits are all low energy circuits which do not
produce any significant heat or heat dissipation
problems.
Type MC, MI and TC [See Section 336.4(3)] cables
may be installed in ladder, ventilated trough, or
ventilated cable channel, but they are not allowed to
be installed in solid bottom cable trays.
Required Spacing in Cable Trays for Type MC, MI & TC
Cables in Class II, Division 2 Hazardous (Classified) Areas
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