13
Instruction Booklet
IB022003EN
Effective April 2018
Revision #3
Instructions for installation, operation, and
maintenance of Type MVS-ND, metal-enclosed
switchgear assemblies: 4.76 kV or 15.0 kV class
EATON
www.eaton.com
Duplex switchgear configuration
When supplied, the duplex configuration consists of two vertical
sections containing MVS-ND switches connected together by a
common bus on the hinge terminals of each switch . This, in turn,
is connected to one set of fuses located in one of the switch
compartments . This arrangement allows the selection of either
of two incoming lines .
Figure 7. Duplex Selective Switch Operation.
This arrangement is always supplied with key interlocking for safe
operation . Key interlocking consists of a lock on each switch to lock
the switch in the open position and a lock on each door to lock each
door closed . Each of the locks is keyed alike and only one key must
be available to operating personnel . Since the key is retained in its
lock when a switch is closed or when a door is opened, two things
are assured:
•
Only one switch may be closed at a time to prevent paralleling
of incoming lines
•
Both switches must be locked in the open position to unlock
either main door, preventing access to energized load side bus
or fuses
WARNING
ONLY ONE KEY SHOULD BE AVAILABLE TO OPERATING PERSONNEL FOR
THIS INTERLOCK SCHEME. WHEN SHIPPED FROM THE FACTORY, EACH
LOCK WILL HAVE A SEPARATE KEY. ALL EXTRA KEYS MUST BE DESTROYED
OR OTHERWISE MADE INACCESSIBLE TO OPERATING PERSONNEL.
FAILURE TO DO SO COULD RESULT IN SEVERE INJURY OR DEATH.
MVS-ND switchgear bolt tightness for
bus connections
Use the following torque value for tightening bus joints .
Table 7. Bolt Torque Values for Bus Connection.
Recommended Spiralock Applied Torque
Bolt Size
ASTM A 449; SAE J429 Grade 5
Dry
Nominal Torque
1/4-20
12 ft-lbs (16.3 N
·
m)
3/8-16
45 ft-lbs (61 N
·
m)
1/2-13
50 ft-lbs (67.8 N
·
m)
