A
universal system
Cable preparation
and installation techniques for Raychem
high voltage joints are identical to those
for Raychem heat-shrinkable terminations.
The same basic design is also shared by
Raychem joints for paper insulated cables.
In this respect too, the heat-shrinkable
system sets new standards of efficiency
and simplicity.
Electrical field control
The stress control tubing has precisely
defined impedance characteristic which smoothens
the electrical field over connector and
cable screen ends. During installation of
tubing, its shrinking action compresses
the special void filler (yellow) into position
round the screen ends and connector. Pencilling
of insulation at the connector is not necessary.
Product design
The design of a single-core joint for polymeric
insulated cable is described here. The same
design principles are used for 3-core and
paper insulated cables.
Insulation and screen
The elastomeric sleeve provides correct
thickness of insulation (red) in one step.
The insulation screen is provided by the
outer wall of the sleeve, which is of heat-shrinkable
conductive polymer (black). This technique
saves installation time and ensures flawless
bond between joint insulation and screen.
Mechanical strength
for steel wire or tape armoured cables.
Raychem joints incorporate a light-weight
impact-resistant galvanised steel joint
case which is quick to install and provides
earth fault current capacity.
Outer sealing
Heat used to shrink the outer sleeve causes
pre-coated adhesive to melt and flow, resulting
in lasting moisture and corrosion barrier
on the cable oversheath.
Metallic shielding
Tinned copper mesh of adequate cross-section
provides electrical continuity of insulation
shield across the connection area.
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