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Cable layout
163
857-164342 / Rev.C
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 cabin, must, unless
shielded by a metal deck or bulkhead, be adequately screened by
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. Cables which must pass through a radio
room must be screened by a continuous metal conduit or
trunking which must be bonded to the screening of the radio
room at its points of entry and exit.
Physical protection
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 (e.g. 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.
Grounding
All metallic cable coverings (armour, lead sheath etc.) must be
electrically connected to the vessel’s hull at both ends except in
the case of final sub-circuits where they should be connected at
the supply end only.
Grounding connections should be made using a conductor which
has a cross-sectional area related to the current rating of the
cable, or with a metal clamp which grips the metallic covering
of the cable and is bonded to the hull of the vessel. These cable
coverings may also be grounded by means of glands specially
intended for this purpose and designed to ensure a good earth
connection. The glands used must be firmly attached to, and in
good electrical contact with, a metal structure grounded in
accordance with these recommendations.
Electrical continuity must be ensured along the entire length of
all cable coverings, particularly at joints and tappings. In no case
should the lead-sheathing of cables be used as the only means of
grounding cables or units.