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Tandem ELF current-limiting dropout fuse installation instructions
INSTALLATION INSTRUCTIONS   MN132029EN   November 2016
CAUTION 
Eaton’s Cooper Power series Tandem ELF Fuse is 
designed to be installed in accordance with normal 
safe operating procedures. These instructions are not 
intended to supersede or replace existing safety and 
operating procedures. Read all the instructions before 
installing the Tandem ELF Fuse. The Tandem ELF Fuse 
should be installed and serviced only by personnel 
familiar with good safety practice and the handling of 
high-voltage electrical equipment.
Product information
Introduction
Eaton’s Cooper Power series Tandem ELF current-limiting 
fuse is designed for transformer protection. The Tandem ELF 
fuse can be applied for fusing single-phase transformers 
and for fusing three-phase transformers (or three-phase 
banks of single-phase transformers). This fuse combines the 
features of a series fuse link and a backup current-limiting 
fuse in one package. The Tandem ELF fuse (refer to Figure 
1) features a unique design for fast replacement of the 
fuse link after a low fault current operation or excessive 
transformer overload current or replacement of both the 
fuse link and backup current-limiting fuse after a high fault 
current operation. Note that when using recommended fuse 
links or other properly coordinated fuse links, the fuse link 
will operate to provide for the dropout action of the Tandem 
ELF fuse following an interruption.
Read this manual first
Read and understand the contents of this manual and follow 
all locally approved procedures and safety practices before 
installing or operating this equipment
Additional information
These instructions cannot cover all details or variations 
in the equipment, procedures, or process described nor 
provide directions for meeting every possible contingency 
during installation, operation, or maintenance. When 
additional information is desired to satisfy a problem not 
covered sufficiently for the user’s purpose, please contact 
your Eaton representative.
Figure 1.  Tandem ELF fuse assembly
Upper contact
Upper pull ring 
connector
Pull ring
Backup 
current-
limiting 
fuse
Fuse link 
holder
Lifting eye
Fuse cap
Acceptance and initial inspection
Each Tandem ELF fuse is completely inspected and tested 
at the factory. It is in good condition when accepted by 
the carrier for shipment. Upon receipt of the Tandem ELF 
fuse, inspect the connector thoroughly for damage and 
loss of parts incurred during shipment. If damage or loss is 
discovered, file a claim with the carrier immediately.
Table 1.  Recommended ELF current-limiting dropout fuse voltage ratings
Coordinates with fuse links up through
Backup current-
Limiting fuse
Edison
type D
Kearney
type X
Kearney
type QA
NEMA
type K
Kearney
Type 200 
Edison
type N
NEMA
type T
Edison
type H
Kearney
type KS
25 K 20 10 30 25 20 30 15 8 7