S&C VacuFuse, Installation And Operation Manual

10    S&C Instruction Sheet 465-500

Installation

Installing a VacuFuse Self-Resetting 

Interrupter into the Cutout Mounting

 WARNING

Provide training to line crews on the use of both a 
hotstick and an extendostick before installing or 
operating the VacuFuse Self-Resetting Interrupter . 
The VacuFuse interrupter is different from other 
cutout-mounted devices . Failure to properly handle 
a VacuFuse interrupter with a hotstick and/or an 
extendostick may lead to serious injury or death .

STEP  1.  

If using an existing S&C cutout mounting 
or other approved cutout mounting

:

 Visually 

inspect the cutout mounting for damage or 
excessive wear, particularly in the upper 

and 

lower contact areas. If ANY damage is visible, 
replace the cutout mounting before proceeding. 
DO NOT install and/or energize a VacuFuse 
Self-Resetting Interrupter into a damaged 
cutout mounting.

If installing in a new S&C cutout mount-

ing

: For overhead pole-top style VacuFuse Self-

Resetting Interrupters, attach the mounting to 
its mounting bracket, as illustrated in Figure 4. 
A mounting bracket, suitable for crossarm, pole, 
or wall mounting, is furnished only if specified 
through the addition of catalog number suffix 
“-B” or “-C” to the VacuFuse interrupter catalog 
number. 

Note the placement of the external-tooth 

lockwasher between the mounting bracket and 
the center insert of the mounting. Pivot the 
mounting bracket to a position that will provide 
maximum ease of operation, and then securely 
tighten the carriage-bolt nut.

STEP  2.  

Make the electrical connections to the cutout 
mounting. If aluminum conductors are used, be 
sure to wire-brush them and apply a coating of 
oxidation inhibitor before inserting them into 
the connectors. 

STEP  3.  

Installation Using Insulated Gloves

: With 

the OPEN/CLOSE lever in the 

Open

 position, 

insert the VacuFuse Self-Resetting Interrupter 
into a 125-kV BIL- or a 150-kV BIL-rated 
mounting with gloved hands, as shown in 
Figures 5 and 6. Guide the trunnion into the 
hinge of the cutout mounting, as shown in 
Figure 6.

Figure 6. Guiding the trunnion into the hinge of the cutout 

mounting using gloved hands.  

Figure 5. Bringing the trunnion close to the hinge of the 

cutout mounting. 

Carriage-bolt
Carriage bolt nut

Lockwasher

Mounting 

bracket

Overhead pole-

top mounting 

center insert

External 

tooth 

lockwasher

Figure 4. Attaching an overhead pole-top style VacuFuse 
interrupter cutout mounting to the mounting bracket.

Trunnion