Simrad SP90 - REV E, Installation Manual

Page: 96 / 232

Simrad SP90
84
851-164510 / Rev.E
7.8 Basic cabling requirements
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 (max. 0.5 metre) 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.
•
Cables having a copper sheath or braiding must be installed
in such a way that galvanic corrosion by contact with other
metals is prevented.
•
To allow for future expansion of the system, all cables should
be allocated spare conductor pairs. Also, space within the
vessel should be set aside for the installation of extra cables.