Technical data

Bus bar insulation
Bus bars are insulated using heat-shrink
insulation. Bolted bus joints are insulated
by pre-formed molded boots, which are
held in place by nylon hardware. For bus
configurations where no boot design is
available, taped joints are used. The main
bus is supported with cycloaliphatic
epoxy inserts where the bus passes from
one section to another. Other bus is
supported using porcelain standoff
insulators. Circuit breaker support
insulators and cubicle primary disconnect
supports are molded epoxy. Interphase
and other barriers are track-resistant,
flame retardant glass polyester.
Bus joint insulation
For normal joint configurations, bolted
bus joints are insulated by pre-formed
molded polyvinyl boots (double), which
are held in place by nylon hardware.
Preformed insulating materials eliminate
the need for molding and taping joints
when connecting shipping groups in the
field, reducing installation time and
costs. The same preformed, high-
dielectric strength joint boots used in
factory assembly are also used in field
assembly of shipping-split bus
connections. For uncommon joint
configurations, taped joint insulation is
used. Boots for insulating user’s power
connections are available as an option.
Bus support insulation
Bus bars are supported on porcelain
standoff insulators using a glass-
polyester saddle-clamp system. Inter-unit
bus is supported on cycloaliphatic epoxy
inserts mounted in a glass-polyester
sheet.
Wiring
The secondary and control wiring is
connected to terminal blocks, which have
numbered points for identification. One
side of the terminal blocks for
connections leaving the switchgear is
reserved for external connections.
Secondary and control wire is minimum
No. 14 AWG, extra-flexible, stranded type
SIS wire, insulated for 600 volts, except
when devices (for instance, transducers,
communicating devices, etc.) require
different wire. Insulated barrel, crimp-
type locking fork terminals are used for
most applications, except where the
devices require a different type of
terminal. Where they pass through
primary compartments, secondary
control wires are armored or enclosed in
grounded metal wire covers or sheaths.
Construction
11
Figure 10: Main bus construction
Figure 11: Cell wiring