Kongsberg EM 122, Installation Manual

Page: 150 / 154

EM 122
Appendix B
Basic cable
requirements
This appendix provides general information related to the installation and maintenance
of system cables.
Cable trays
All permanently installed cables associated with the system must be supported and
protected along their entire lengths using conduits and/or cable trays. The only exception
to this rule is over the final short distance (maximum. 0,5 meters) as the cables run into
the cabinets/units to which they are connected. These short service loops are to allow the
cabinets to move on their shock mounts, and to allow maintenance and repair.
• Wherever possible, cable trays must be straight, accessible and placed so as to avoid
possible contamination by condensation and dripping liquids (oil, etc.). They must be
installed away from sources of heat, and must be protected against physical damage.
Suitable shields must be provided where cables are installed in the vicinity of heat
sources.
• Unless it is absolutely unavoidable, cables should not be installed across the vessel's
expansion joints. If the situation is unavoidable, a loop of cable having a length
proportional to the possible expansion of the joint must be provided. The minimum
internal radius of the loop must be at least twelve times the external diameter of
the cable.
• Where a service requires duplicate supply lines, the cables must follow separate paths
through the vessel whenever possible.
• Signal cables must not be installed in the same cable tray or conduit as high-power
cables.
• Cables containing insulation materials with different maximum-rated conductor
temperatures should not be bunched together (that is, in a common clip, gland,
conduit or duct). When this is impractical, the cables must be carefully arranged
such that the maximum temperature expected in any cable in the group is within the
specifications of the lowest-rated cable.
• Cables with protective coverings which may damage other cables should not be
grouped with other cables.
148
317669/B