14
SA FEG E A R®
5/ 1 5 K V, U P TO 5 0 K A A R C- R E S I S TA N T S W I TC H G E A R
Main bus compartment
All primary buses are copper with a corona-free
design, and are available in 1200, 2000, 3000 and
4000 A ratings (4000 A rating achieved by forced
air cooling). The bus is silver-plated at joints and
bolted together with a minimum two (2) half-inch
SAE grade 5 bolts. Proper torque is verified by
calibrated tools for both safety and optimum
performance. The main bus is not tapered and is
easily extended at both ends to facilitate future
expansions.
The bus is epoxy insulated with an advanced
powder coating system that eliminates voids and
other potential defects, resulting in maximum
integrity of the insulation system. Removable,
reusable boots are provided at each joint to
simplify access and maintenance.
Insulating standoffs rigidly support the bus. This
includes risers, the connections from stationary
primary contacts to the main bus and runbacks the
connections from the stationary primary contacts
to line or bus terminations. Internal standoffs and
inter-frame supports are polyester for 1200 A and
2000 A applications, porcelain for 3000 A
applications, and epoxy for 4000 A applications.
Porcelain bus supports are available as an option.
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Compartment types
Bus compartment
SafeGear arc-resistant, metal-clad switchgear
design certifications are based on both polyester
and porcelain primary bus supports. Separate
drawings are available to indicate the position and
dimensions of the compartment-mounted primary
contact supports, inter-frame horizontal bus
supports, and standoff insulators.
Characteristic
Epoxy
Flexural strength, MPA
120 - 150
Tensile strength, MPA
70 – 90
Impact strength, KJ/m2
10 – 15
Thermal class
F
Dielectric strength (short time), kV/mm
> 23
Characteristic
Glass polyester
Porcelain
Flexural strength,
psi
15-27,000
10,500
Tensile strength,
psi
14,000
6,000
Izod impact, ft-lb
per inch of notch
6-12
1.5
Thermal shock,
cycles 32°- 2300°F
100+
1
Dielectric strength
(short time), vpm
.125” thick, 25°C
350-375
300
Dielectric
constant
4-6
6
