GE Industrial Solutions AKD-20 Low Voltage Switchgear - Manuel (Page 35)

AKD-20 Low Voltage Switchgear
Chapter 4. Equipment Installation
35 ©2012 General Electric All Rights Reserved
The ground bus is mounted directly on the rear upright channels.
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.
NOTE: Il est particulièrement important que la barre omnibus de
mise à la terre soit branchée en premier, étant donné qu’elle
fournit une mise à la terre intégrale à tout l’équipement. Elle doit
aussi être branchée à la mise à la terre du poste avant de
procéder à la 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. Plan view of ground bus splice installation
Figure 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 GE 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.
Fig. 4-12. Flange opening on a transition section to a GE
transformer
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.
Ground bus
connection