KS 3-2010
Page 3
Section 2
SAFETY PROCEDURES
The inspection and preventive maintenance of switches in service require the user to take all necessary
precautions to avoid being injured.
2.1 Warning
2.1.1 Switch Testing
WARNING—Hazardous voltages in electrical equipment can cause death or severe personal
injury. Turn off and lock out the power supplying this equipment before performing any of the
following operations.
Unless otherwise specified in this publication, inspection, preventive maintenance, and testing must always
be performed on equipment that is de-energized (note that certain tests require control power to conduct the
test). Verify that there is no voltage present on incoming line and load terminals (and on control power
terminals, if present) and between these terminals and ground to positively ascertain that the equipment is
totally de-energized. The disconnecting or isolating means on the line side of the devices being checked
and/or tested must be locked in the OFF position to ensure that the equipment will remain de-energized
during these procedures.
Safety related work practices described in NFPA 70E must be followed at all times.
2.1.2 Test Equipment
WARNING—High voltages involved with some test equipment can cause death or serious injury.
Do not touch or permit anyone else to touch the switch or the test leads when voltage is applied.
Strict adherence to the safety procedures recommended by the manufacturers of the test
equipment is required.
2.2 Safety Procedure
In all the following clauses, where removal of the enclosure cover is necessary, the following safety steps
must be taken in the sequence shown.
2.2.1 Operate the switch to the OFF position. Turn OFF all power supplying the switch to electrically
isolate it from all other circuits.
2.2.2 Open the enclosure and verify that there is no voltage on the incoming and load conductors
(including control power conductors, if present) and between these conductors and ground to
positively ascertain that the equipment is de-energized.
2.2.3 If disconnection of power and accessory leads, cables, or bus bars is required, be sure to
properly identify all connections to ensure safe and accurate reconnection.
2.2.4 Before any functional tests are performed, be sure to connect the test switch with properly rated
cable torqued to the recommended values marked on the rating label of the switch.
2.3 Reinstallation Safety Procedure
2.3.1 Do not re-energize equipment until all connections (power and control) are thoroughly checked
for accuracy and tightness (torqued to value listed on the rating label), internal areas of
enclosure are cleaned of any conductive loose parts or debris, all switches are turned off, and
all enclosure covers are reinstalled.
© Copyright 2010 by the National Electrical Manufacturers Association.
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