DEH-41473
AKD-20 AR / Entellisys AR Low-voltage Switchgear
Section 3. Switchgear Description
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Insulated/Isolated Bus System
A bus insulation system (Figure 3.24) that fully insulates and
isolates each phase of the horizontal main bus and isolates
each phase of the vertical bus, is available for AKD-20 AR and
Entellisys AR switchgear as standard construction. With the
INSULATED/ISOLATED BUS system, there are no live
connections accessible in the rear of each section except the
cable lugs.
Insulation and isolation of the vertical riser bus bars (Figure
3.21) is provided by installing phase isolation barriers (not
shown) between the bus bars and by the vertical bus barrier
which covers over the bus bars.
The phase isolation barriers and riser bus covers are
constructed from insulating material. Insulation of the
horizontal main bus bars is achieved by an oven cured
coating of epoxy.
The vertical/horizontal bus bar joints are covered with collars
and caps (Joint Cap) held in place with nylon thumb screws.
The collars and caps are constructed from insulating material.
A vertical section barrier (Figure 3.25) between adjacent
sections of equipment is always furnished. The section
barrier provides a separating barrier system between
adjacent bus and cable compartments while allowing the
horizontal main bus to progress through adjacent sections.
Figure 3.23 illustrates the various components comprising the
vertical main bus bars. Bus bars are supported by molded or
machined barriers. Vertical bus can be braced depending on
the interrupting rating of the switchgear. Conductors that
provide current to the breaker compartments are called run-
in bars and are bolted to the riser bus bars. Insulated run-
back bars are for connecting load conductor cabling.
Figure 3.23 Insulated horizontal bus system
(1)
Vertical Bus Cover
(2)
Insulated Bus Bar (Epoxy Coated)
(3)
Joint Cap
(4)
Nylon Thumb Screw
Figure 3.24 Insulated/Isolated bus system
(1)
Upper Neutral Bus with 4
th
Wire Sensors
(2)
Vertical Riser Bus Covers
(3)
Run-backs to Feeder Cable Connections
(4)
Horizontal Main Bus
Figure 3.25 Section barrier system
(1)
Section Barrier
