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IQ 310A XCPD Technical/Service Manual
2.3
Cabling and Conduit Runs
2.3.1
Cabling
There are two types of cables that pass through a sealoff fitting, single conductor and multi conductor.
Single Conductor Cabling
Single conductor cables are typically redundant ground wires (used with resistive intrinsic safety barrier). Due to
the nature of the method by which insulation is applied to wire, a single conductor wire (single or multi strand)
can be considered gas tight. It is not necessary to strip the insulation back ahead of entry into the safe area. Single
conductor cables will pass through a sealoff fitting as shown below.
Figure 2-1. Single Conductor Cable
Multi Conductor Cabling
Multi conductor cables may be load cell cables, AC power, serial data inputs or other signals. Because of the
airspace that typically exists within the outer insulation of a multi conductor cable, they cannot be considered gas
tight. Therefore, to insure that the explosion proof enclosure is allowed to vent internal pressure appropriately,
the outer insulation must be removed back to the point ahead of entry into the safe area. Multi conductor cables
will pass through a sealoff fitting as shown below.
Figure 2-2. Multi Conductor Cable
A sealing fitting must be installed within 18" of the enclosure for Groups C-G and 6" for Groups A and B.
Using the enclosed packing fiber and sealing cement, follow the directions for sealing the sealoff fittings
carefully. Make sure there are no openings, no matter how small to the outside.
An enclosure without sealoff fittings correctly installed and sealed is not explosion proof
therefore can pose serious injury or death.
Conduit to Indicator or other Safe
Area ( 18” Max. Group C & D)
Packing Plug
Safe Area
Airspace
Hazardous Area
Airspace
Conduit or Strain Relief
to Hazardous Area
Packing Fiber
Sealing Cement
Single
Conductor
Cable
Conduit to Indicator or other Safe
Area ( 18” Max. Group C & D)
Packing Plug
Safe Area
Airspace
Hazardous Area
Airspace
Conduit or Strain Relief
to Hazardous Area
Packing Fiber
Sealing Cement
Multi-Conductor
Cable
Warning
DISCONTINUED
