38
4 . eq u I p m eN T I N s Ta L L aT I o N
—
Fig. 4.11
Plan view of ground
bus splice installation
—
Fig. 4.11
Ground bus
The ground bus is mounted directly on the rear
upright channels in each individual section.
Note: It is particularly important that the
ground bus be connected first since it
provides an integral ground for all the
equipment. It must also be connected
to the station ground prior to proceeding
with the installation.
Remarque: Il est particulièrement important
que le jeu de barres de mise à la terre soit
connecté en premier car il fournit une mise
à terre intégrale pour l'ensemble de
l'équipement. Il doit également être relié au
sol avant le début de l'installation.
A 4/0 AWG cable connector is located in the bottom
of the transition section (or in the incoming line
compartment if a transition section is not
included) for terminating the purchaser's cable
connection to ground. The specific location of the
station ground connection is shown on the site
floor plan drawing and in the electrical drawings
supplied with the equipment. All grounding of the
switchgear should be in accordance with National
Electrical Code.
Fig. 4.11 illustrates the installation of the ground
bus splice plate across a shipping split. In addition
to the bolted fastening of the splice plate to the
two ends of the ground bus, self-tapping 1/4-20
bolts pass through the splice plate and ground
bus stubs, and thread into the equipment frame.
These bolts should be fastened with a torque
of 7–9 ft-lbs.
If a transformer (rated above 750 kVA) is present in
the line-up, a ground bar located in the transition
compartment, Fig. 4.12, is provided for connection
of the transformer ground pad to the equipment
ground termination point.
1
1. Ground bus
—
Fig. 4.12
Flange opening on a
transition section to
a GE transformer
—
Fig. 4.12
As shipped, the ground bar is mounted so it
does not protrude beyond the outer surface of the
equipment. When the equipment is installed in its
final location, the ground bar must be reassembled
using the outer bolt holes in the horizontal ground
bus spanning the width of the transition
compartment. In this mounting location, the offset
portion of the ground bar will permit connection
to the transformer ground pad with the 1/2-13 bolt
assembly supplied with the switchgear equipment.
If an optional floor plate is supplied for the
transition compartment, it will be necessary to
remove the floor plate to permit relocation of the
ground connection bar.
All bolted bus joints should be made using the
proper torque as shown in Table A.1 in Appendix
A of this manual. Transformers not manufactured
by ABB may require special mounting and bus
connection hardware.
