S&C Instruction Sheet 466-500 3
Introduction
The VacuFuse II Self-Resetting Interrupter, selected for a specific application, should have a
maximum voltage rating equal to or greater than system line-to-line voltage when used in phase-
to-phase applications. The VacuFuse II Self-Resetting Interrupter can be applied on the primary
side of 7.2-kV overhead distribution transformers up to 150 kVA and on 15-kV transformers up to
250 kVA when mounted in a 110 or 125/150 kV-BIL cutout mounting. To ensure proper performance,
VacuFuse II interrupters must only be installed in present-production (“-R10” or “-R11”) S&C-provided
cutout mountings. See the example in Figure 1. An example of an earlier-production S&C cutout
mounting is shown in Figure 2.
Figure 1. A present-production (“-R10” or
“-R11”) S&C-provided Type XS Fuse Cutout
mounting.
Figure 2. An earlier-production (“-R9”) S&C
Type XS Fuse Cutout mounting. “-R8” and
earlier versions have a similar upper contact.
