TM
5-811-1/AFJMAN
32-1080
components for maintaining symmetrical stress
ing. Whenever separable insulated connectors are
distribution, minimizing voltage gradients, and
used for this application, they should be of the
maximizing environmental protection.
loadbreak type. The preformed kit must be suit-
(1) Connectors. Connectors will be of the com-
able for the cable insulation and correctly sized for
pression type or the plug-in type. Mechanical
the cable diameter. Separable insulated connectors
connectors of the bolted or screw type or thermal
will not be used in manholes, except where neces-
connectors of the soldered, brazed, or welded type
sary for reasons of clearance at airfields. Separable
will be used only in special cases where the
insulated connectors will not be used in direct
application so warrants. Compression connectors
burial applications.
(3) Choice. Any of the cable joints discussed
above 5 kV need to be of the tapered-end type, or
have semiconducting (semicon) tape or molded
may be permitted as a Contractor's option, whose
construction to give the same effect and thus limit
selection is made by balancing labor savings
stresses.
against material costs. Disconnectable loadbreak
(2) Other necessary joint components. The
separable connectors, which are the most expen-
other necessary components are contained with the
sive type of cable joints, will be used only where
connectors in kits to provide joints which range
the disconnect feature is necessary. Metallic-
from the fully field-assembled type (taped) to those
armored cable splices will be enclosed in
kits with mostly factory-formed parts (preformed)
compound-filled metal splice boxes. Splice and
which require less installation labor. Factory pre-
terminator kits will be selected as recommended
formed kits are preferred. The field-assembled kits
by the cable manufacturer.
(4) Dissimilar material. Both aluminum-to-
will not be used unless the Contractor cannot
locate the preformed kits, and the Contractor
copper conductor and nonmetallic-jacketed to lead-
covered cable connections are easily made when
employes a cable splicer approved by the Contract-
ing Officer.
connectors and splicing materials are correctly
(a) Conventional taped or resin system splice
utilized and installed. While transitions from one
kits. These kits cost the least for materials and are
material to another will not be permitted when
used to make up a significant number of cable
installing new lines, such transitions between
joints, but this type requires the most labor to
existing and new work are acceptable for exten-
install. Joints are longer and bulkier than other
sions and additions.
e. High-voltage cable terminations. A device used
types. Quality is dependent upon the splicer's skill
level, so joint workmanship can vary widely. Any
for terminating alternating-current power cables
having extruded, solid, or laminated insulation
kit selected must have splice tapes suitable for the
which is rated 2.5 kV and above is known as a
cable insulation. Refer to IEEE Std 141 for details
high-voltage cable termination.
and specifications of cable joints.
(b) Heat-shrinkable splice kits. These kits
(1) Provisions. Such terminations are covered
by IEEE Std 48 which requires terminations to be
include factory preformed splices which are heat-
treated in the field to fit the conductor. This type
able to provide one or more of the following:
(a) Electric stress control for the cable insu-
is simpler to install than the conventional taped or
lation shield terminus.
resin type, and provides a less bulky splice than
(b) Complete external leakage insulation be-
any of the other types. A kit will fit a range of
tween the cable conductors and ground.
cable sizes, but kits may not be available for other
(c) A seal at the end of the cable against the
than solid dielectric single-conductor cables.
(c) Separable insulated connectors. Such con-
entrance of the external environment which also
maintains the pressure, if any, of the cable system.
nectors are fully factory preformed into the mini-
(2) Types. Termination types are defined by
mum of parts necessary to adapt either the recep-
IEEE Std 48 as Class 1, which provides all of the
tacle and plug or the connector and splice body to
above three conditions (and includes potheads, a
the cable insulation, shielding, and jacket. Such
term now rapidly becoming obsolete), Class 2
joints cannot be used for laminated insulations,
which provides the first two conditions, and Class
but provide a waterproof and totally submersible
3 which provides only the first condition. The first
joint for solid or extruded dielectric insulations.
two classes include both indoor and outdoor types,
These joints are the quickest to install, but the
but Class 3 can only be used indoors. Protection
labor savings may be outweighed by the highest
from direct exposure to solar radiation or precipi-
initial cost. Greater reliability has been reported
tation is required for outdoor types.
by utility and industry records for these joints.
(3) Requirements. Class 2 terminations with
Connections do provide disconnectability for future
their unsealed ends are subject to tracking when
taps or for cable sectionalizing during fault test-
7-4
Previous Page
