maintenance-free, SF6 filled, molded epoxy insulated case, surrounded by
dead-front metallic barriers. Switch operation shall be controlled by
permanently lubricated quick-make, quick-break spring operator with solid
linkage connection to contact operating shaft. Switch operator shall be
mounted in separate dead-front compartment with access for addition of
remote or automatic accessories, and shall include removable operating
handle with storage provision, positive position indicators, and padlock
provisions. SF6 gas shall conform to ASTM D 2472.[ Fused load interrupter
switches shall be provided with clip-style, mounted air-insulated current
limiting fuses and molded epoxy interphase barriers. Provide neon voltage
indicators for blown fuse indication.] Load interrupter switch shall be
rated [_____] continuous, [_____] kA momentary, [_____] kA short-time fault
closing.
][2.2.8.3
Vacuum-Insulated Load Interrupter Switches
Circuit interrupting device shall be [fused][non-fused], fixed mounted,
[manually][electrically] operated, and shall be quick-make, quick-break
with speed of operation independent of the operator. Electrically operated
device shall be [120 Vac][125 Vdc]. Spring charging mechanism shall not
rely on chains or cables.[ Motor operator assembly shall be a separate
device, isolated from high voltage and coupled through a direct drive
shaft.] Circuit interrupter shall consist of automatic visible blade
disconnects in series with vacuum interrupters. Arc interruption shall
take place within the envelope of the vacuum interrupter. Upon opening,
contacts in the vacuum interrupter shall separate 12 to 18 milliseconds
before disconnect blades open. Total circuit interrupt opening time shall
not exceed 3.0 cycles after the trip coil is energized at 85 to 100 percent
of rated control voltage. Upon closing, disconnect blades shall close 9 to
12 milliseconds before contact is made in the vacuum interrupter. Local
interrupter switch shall be rated [_____] continuous, [_____] kA momentary,
[_____] kA short-time fault closing.
][2.2.8.4
Fuses
**************************************************************************
NOTE: Other fuse types may be specified if more
appropriate to the project.
**************************************************************************
IEEE C37.41 and NEMA C37.46 as applicable. High-voltage fuses and
non-disconnecting fuse mountings shall be accessible only through a
separate door mechanically interlocked with the load break switch, to
ensure the switch is in the open position when fuses are accessible.
Switch shall be designed with full height fuse access doors and shall have
a solid barrier covering the area of the main cross bus and line side of
the switch. Metal screen barriers are not acceptable. No energized parts
shall be within normal reach of the opened doorway. Four single full
length interphase barriers shall isolate the three phases of the switch
from each other and from the enclosures. Fuses shall be [current limiting
type of self-contained design to limit available fault current stresses on
the system and shall have interrupting capacity [as indicated][of [_____]
amperes symmetrical rms].][boric acid type with provisions for refill units
complete with muffler exhaust. Furnish three spare fuse refill units for
each switch and fuse assembly.] Fuses shall be affixed in position with
provisions for removal and replacement from the front of the gear without
the use of special tools.
SECTION 16361N
Page 33
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