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24
Installation
01.4IB.51000C
PowlVac® Metal-Clad Switchgear
5kV & 15kV
J. c
onnectIonS
The main bus bars and other connection bars
are copper. The connection surfaces are silver
surfaced or equivalent. The silver plating used
on bolted contact surfaces is approximately
0.0001” thick. All field assembled joints in
primary conductors, regardless of method of
installation, should be made as follows:
1. Wipe the surface clean with a lint free cloth.
Do not use sandpaper or any abrasive
on the plated surface. Avoid handling of
cleaned surface as much as possible. If
the surface is tarnished, clean it with silver
polish and then wash it with denatured
alcohol.
2. Join the clean contact surfaces by using the
hardware provided. The correct length of
bolt must be used in each joint to ensure
that electrical clearances at bolt locations
are maintained. As a general rule, when
using ½” diameter bolts, the bolt should be
1” longer than the combined thickness of
the copper bars being bolted together. For
example, if three ¼” thick copper bars are to
be connected, the bolt should be 1¾” long.
In addition to proper length bolts, the bolt
assembly must include flat washers, split
ring lock washers, and nuts. All hardware
must be SAE Grade 5 or better. Refer to
Figure 15 for proper assembly of hardware.
Figure 15 Ground Bus Splice Plate Connection
a
b
c
d
e
a. Bolt
b. Flat Washer
c. Bus Bar
d. Split Lock Washer
e. Nut
!
CAUTION
All exposed primary bus and cable joints and
connections must be insulated to the system
insulation rating.
3. In some cases, external connections are
made to the equipment main bus by bars.
The equipment bars are normally silver
plated. Unplated bars either copper or
aluminum should not be used to connect
to plated bars.
4. All field assembled primary conductor
joints and terminations must be insulated
for the operating voltage. There are two
methods of insulating the joints: Taping
joints or applying boots where applicable.
A detailed procedure for joint insulation
is described in
.
Note:
All hardware must be tightened to the
torque values listed in Table C, Bolt