PB 1.1-2007
Page 13
Section 7
STEPS TO BE TAKEN BEFORE ENERGIZING
7.1 ACCESSIBLE ELECTRICAL CONNECTIONS
Tighten all accessible electrical connections to the manufacturer's torque specifications. If such information
is not provided with the equipment, consult the manufacturer.
7.2 BLOCKS AND PACKING MATERIALS
Make certain that all blocks and packing materials used for shipment have been removed from all
component devices and the panelboard.
7.3 SWITCHES, CIRCUIT BREAKERS, AND OTHER OPERATING MECHANISMS
Manually exercise all switches, circuit breakers, and other operating mechanisms to make certain they
operate freely.
Check the integrity of all electrical and mechanical interlocks and padlocking mechanisms. For key
interlocked systems, assure that only the required number of keys are accessible to the operator.
7.4 SHORT CIRCUITS AND GROUND FAULTS
To make sure that the system is free from short circuits and ground faults, conduct an insulation resistance
test phase to ground and phase to phase with the switches or circuit breakers in both the open and closed
positions. If the resistance reads less than 1 megohm while testing with the branch circuit devices in the
open position, the system may be unsafe and should be investigated. If after investigation and possible
correction, low readings are still observed, the manufacturer should be contacted. Some electronic
equipment (metering, TVSS, etc.) may be damaged by this testing. Refer to the manufacturers equipment
markings for guidelines.
7.5 GROUND FAULT PROTECTION SYSTEM
Test the ground fault protection system (if furnished) in accordance with the manufacturer's instructions. See
Section 230.95 of the National Electrical Code and NEMA Standards Publication PB 2.2, Application Guide
for Ground Fault Protective Devices for Equipment.
7.6 ADJUSTABLE TIME CURRENT TRIP DEVICE SETTINGS
Set any adjustable time current trip device settings to the proper values.
NOTE—Experience has indicated that damage from overcurrent can be reduced if the devices used for overload and short-circuit
protection are set to operate instantaneously (that is, without intentional time delay) at 115 percent of the highest value of phase current
which is likely to occur as the result of any anticipated motor starting or welding currents.
7.7 GROUNDING CONNECTIONS
Check to determine that all grounding connections are properly made. If the panelboard is used as service
equipment, make certain that the neutral, if present, is properly bonded to the cabinet.
© Copyright 2007 by the National Electrical Manufacturers Association.
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