Kongsberg EM 710, Installation Manual

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Kongsberg EM 710
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 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, 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 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, metallic sheathing 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 appropriate for 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 ground
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 splices. In no
case should the shielding of cables be used as the only means
of grounding cables or units.
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