Power Cable Connections; Relay And Control Devices - GE AKD-20 AR Installation And Maintenance Manual

AKD-20 AR / Entellisys AR Low-voltage Switchgear
Section 4. Equipment Installation

Power Cable Connections

All cables entering or exiting the switchgear assembly must
be enclosed in a conduit. Sealing compound may be used, if
desired. Floor plates are provided as standard.
Connect the main cables to the main lugs. Before any main
cable connections are made, the cables should be identified
to indicate their phase relationship with the equipment.
Adequate electrical and mechanical clearances must be
provided between conduit, cables, and bus. Where the cables
enter the section, they can be lashed to optional cable
supports at the rear of the cable compartment as required.
Mechanical cable terminals are normally included with the
switchgear (compression terminals are supplied when
ordered) and are mounted at the ends of the breaker
runbacks in the cable compartment. Carefully follow the
cable manufacturer's recommendations for installation of
cable.
Install the cables in the proper path to the terminals, using
temporary lashing if required. Cut the cables to the proper
length. Strip the insulation to the desired dimension, being
careful not to damage any strands.
For copper cables, coat the wires with GE lubricating grease
D6A15A2, insert the cables into the terminals, and tighten the
set screws in accordance with torque values shown in the
torque value table for cable terminals in the addendum of this
manual. See Appendix A. Torque Values, Table A-2.
For aluminum cables, wire brush the wire strands thoroughly.
Immediately after wire brushing, coat the cable strands with a
quality oxide inhibiting compound such as Penetrox A. Insert
exposed wires into the terminals and tighten the set screws in
accordance with values shown in the Table A-2 in Appendix A.
Torque Values of this instruction manual.
CAUTION: The torque values shown in the table are for
dry threads only. Do not grease or otherwise lubricate the
threads on the cable terminals as this will permit over
tightening of the screw and possible damage to the
terminal or cable.
This should result in the oozing of compound material from
between individual strands. Wipe off any excess compound.
Bolt the cable terminal connectors to the ends of the bars in
the cable compartment. A non-oxidizing grease, such as GE
lubricating grease D6A15A2 furnished with each equipment,
should be used at these connection surfaces. The bolts
should be tightened in accordance with values shown in
Table A-2 in Appendix A – Torque Values of this instruction
manual.
Lash the cables securely to the optional cable support, if
present, to take their weight off the runbacks and to brace
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them against short circuit forces in the event of a fault. Cable
supports can be optionally ordered from the factory.
The following instructions for cable lashing should be used as
a guide and Figure 4.15 details a typical cable lashing
diagram. Run and bend the main cable in a most convenient
orientation, making sure the main cable has been located
directly up against any cable braces (if present) before it
connects to the main cable terminals. Using a 3/8 inch
diameter continuous nylon rope or equivalent (minimum 2000
pounds tensile strength) at 6 inches from the main cable
terminals, make five revolutions around the "A" and "B" phase
main cables, making sure the rope does not overlap. Make
five revolutions around the "B" and "C" phase main cables.
With the remaining rope, wrap around the main cable lashing
between the "B" and "C" phase and the cable brace (if present)
with a minimum of 5 revolutions getting as much revolutions
as possible between the phases. Continue wrapping between
the "A" and "B" phase around the main cable lashing and the
cable brace (if present) with a minimum of 5 revolutions
getting as much revolutions as possible between the phases.
Securely tie off the remaining rope. Repeat this lashing at
every 6-inch interval.
Figure 4.15 Typical cable lashing

Relay and Control Devices

Remove all blocking on relays and devices as shown in the
instructions accompanying the devices. Protective relays,
devices, trip units and control devices should be set in
accordance with the associated short-circuit coordination
and/or project specifications provided by the customer.
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DEH-41473