MIL-HDBK-1025/10
6.11.1 Closing Network Protectors
WARNING
Do not close a network protector manually, unless specifically
instructed to do so, and then only when it is certain that the medium-
voltage feeder is in service and that the transformer is energized and in
the proper phase relation. When closed by relay, the operation should
be performed only by a worker properly qualified in maintenance of
network protectors.
6.11.2 Network Protector Maintenance Safety. To ensure your safety follow
these rules.
a. Always perform appropriate electrical tests using a three-phase network
protector test kit, before performing any installation or operation of the network
protector.
b. Network protectors are designed to operate within the current and voltage
limitations given on their nameplates. Do not apply these units to systems with currents
and/or voltages exceeding these limits.
c. To perform work on network protectors requires personnel with training and
experience on energized equipment. Only qualified electrical workers, familiar with the
construction and operation of such equipment and the hazards involved should be
permitted to work on network protectors.
d. There are several interlocks on a network protector. They are for personnel
and/or equipment protection. Under no circumstances should they be made inoperative.
e. Roll out the network protector's removable element before making any
adjustments or doing maintenance of any nature.
f. Never energize the network protector without its arc chutes and barriers in
place.
g. Always be sure that all network protector hardware is in place and bolted
tightly before placing a network protector into its housing for operation.
h. Since network protectors are used where a large amount of power is distributed
to heavy-load density areas, any short circuit at any point in the system involves very high
fault currents. Extreme care should be exercised when installing or working on an
energized network protector.
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