S&C ELECTRIC COMPANY
s
INSTRUCTION SHEET
663-503
Page 23 of 35
August 14, 1995
RE-FUSING
How to Detect and
Replace a Blown Fuse
Open the appropriate fuse-compartment door and secure
it with the door holder.
Also remove the dual-purpose front barrier (using the
Grappler) or inner barrier panel, if furnished.
S&C Power Fuses
From a safe distance, observe the blown-fuse target for
the fuse type furnished (refer to Figure 24):
•
SML-20 Power Fuse or Fault Fiter Electronic Power
Fuse—A red blown-fuse target projects from the top of
the SML-20 Power Fuse upper end fitting or the Fault
Fiter Holder when the fuse has operated . . . making it
Ç
WARNING
To minimize exposure to high voltage, close and latch
the adjacent door.
Ç
DANGER
When working in high-voltage compartments, always
maintain proper clearance from energized components.
Failure to maintain proper clearance will result in
serious injury or death.
easy to check the fuse condition with the fuse in the
closed position. The blown-fuse target retracts within
the end fitting or holder when the blown fuse unit or
interrupting module is replaced.
•
SML-4Z Power Fuse—A fluorescent orange target in
the translucent SML-4Z Holder moves to the “BLOWN”
indicator window when the fuse operates, permitting a
positive visual check of fuse condition without remov-
ing the fuse from its mounting. The target fluoresces
when illuminated.
NOTE ON HANDLING:
The current-design upper
end fitting for use in SML-20 Power Fuses, and the
Fault Fiter Holder employ a free-floating blown-fuse
target which can move (by force of gravity) into the
“BLOWN” position should the fuse be inverted during
handling. Fuse condition can be verified by returning
the fuse to the upright position. If the fuse is blown,
the target will remain in the extended (projecting)
position.
Remove the blown fuse from its mounting following
the instructions found under “Opening and Removing the
Fuse” on pages 20 through 22. Then follow the instruc-
tions for replacing blown SMU-20 Fuse Units, SM-4 Refill
Units, or Fault Fiter Interrupting Modules (as applicable)
that are provided with each new fuse unit, refill unit, or
interrupting module.
