S&C Instruction Sheet 465-500
3
Introduction
Proper Application
WARNING
The VacuFuse Self-Resetting Interrupter is only intended for the protection of
distribution transformers . The application must be within the ratings furnished for
the equipment . Ratings for the VacuFuse Self-Resetting Interrupter are listed in the
ratings table in Specification Bulletin 465-31 . They are also etched on the body of
the interrupter .
The VacuFuse Self-Resetting Interrupter, selected for a specifi c 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 Self-Resetting Interrupter can be applied
on the primary side of 5-kV overhead distribution transformers up to 25 kVA, 15-kV
transformers up to 75 kVA, and 25-kV transformers up to 150 kVA when mounted in a
present-production 125- or 150-BIL cutout mounting. For the difference between present-
production and earlier-production cutout mountings, see Figures 1 and 2.
Figure 1. Present-production (“-R10” or “-R11”)
S&C-provided Type XS Fuse Cutout mounting.
Figure 2. Earlier-production (“-R9”) S&C
Type XS Fuse Cutout mounting. “-R8” and earlier
versions have a similar upper contact.
