Kongsberg Simrad SN90, Installation Manual

Page: 173 / 298

381298/C
171
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.
6 Cables with protective coverings which may damage other cables should not be
grouped with other cables.
7 Cables having a copper sheath or braiding must be installed in such a way that
galvanic corrosion by contact with other metals is prevented.
8 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.
Radio frequency interference
All cables that are to be permanently installed within 9 m (30 ft) of any source of Radio
Frequency (RF) interference such as a transmitter aerial system or radio transmitters,
must, unless shielded by a metal deck or bulkhead, be adequately screened
Suitable screening can be established using sheathing, braiding or other suitable material.
In such a situation flexible cables should be screened wherever possible.
It is important that cables, other than those supplying services to the equipment installed
in a radio room, are not installed through a radio room, high power switch gear or other
potential sources of interference. Cables which must pass through a radio room must be
screened by a continuous metal conduit which must be bonded to the screening of the
radio room at its points of entry and exit.
Physical protection of cables
Cables exposed to the risk of physical damage must be enclosed in a steel conduit or
protected by a metal casing unless the cable's covering (for example armour or sheath) is
sufficient to protect it from the damage risk.
Cables exposed to an exceptional risk of mechanical damage (for example in holds,
storage-spaces and cargo-spaces) must be protected by a suitable casing or conduit,
even when armoured, if the cable covering does not guarantee sufficient protection
for the cables.
Metallic materials used for the physical protection of cables must be suitably protected
against corrosion.
Cable layout and interconnections