Switchboard Maintenance; General Maintenance Procedures; Short Circuits; Ambient Temperatures And Circuit Loading - GE ABB ReliaGear SB Installation, Operation And Maintenance Manual

R E L I A G E A R ® S B S W I TC H B O A R D S
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Switchboard maintenance

General maintenance procedures

To obtain the best service from the switchboard,
establish a periodic maintenance schedule. At a
minimum, perform an annual check and overall
maintenance procedure for the switchboard
devices and all connections. Equipment subject
to highly repetitive operation may require more
frequent maintenance.
Keep a permanent record of all maintenance work.
Include a list of periodic checks and tests, the date
they were made, the condition of the equipment,
and any repairs or adjustments performed.
Maintenance employees should follow all
recognized safety practices, such as those in
the National Electrical Code (NEC), the Canadian
Electrical Code (CEC), and in company and other
safety regulations.
For specific information about the maintenance
of devices, such as circuit breakers, relays, and
meters, refer to the separate manuals provided
with each device.
Observe the following important points:
• Periodically inspect the switchboard while
under load to determine if there is any indication
of overheating. If overheating or any other
unsatisfactory condition is found, completely
de-energize the switchboard and investigate.
Look particularly for loose bolts and connections
or overloading. Remove any accumulation of dirt
or other foreign matter in the enclosure. Do not
touch live parts while the switchboard is
energized
• Plated parts may become dark over time due to
oxidation. Do not remove this discoloration, as
this will reduce the thickness of the plating
• Retorque terminal connections and hardware
to the values specified in Table 1 to eliminate
possible heating points. Transmission of
vibrations through the building structure
and conduits to the switchboard may loosen
hardware. Turning the load off and on causes
expansion and contraction between lugs and
cables, which tends to loosen the lug hardware
• Do not open sealed circuit breakers or trip units,
as this may disturb the calibration
• Switchboard enclosures equipped with filters
are recommended to be inspected at least
once a year
• Be sure to return all barriers to their original
locations before re-energizing

Ambient temperatures and circuit loading

Switchboards are designed for installation where
the average ambient temperature does not exceed
40°C (104°F). For higher temperatures, derating is
required. The conductor temperatures within the
enclosure may be as high as 90°C (194°F). Some
parts of the circuit breakers, switches, and fuses
may run hotter. Make sure to follow the load
requirements for each device in the switchboard.

Short circuits

Generally, the overcurrent protective device on the
circuit will prevent any electrical damage except
at the point of the short circuit. Make a thorough
inspection of the entire system after any large
fault current to ensure that there has been no
mechanical damage to conductors, insulation,
or equipment.
In addition, the individual overcurrent protective
device or devices that performed the short-circuit
interruption must be inspected for possible arcing
damage. Do not open sealed devices such as circuit
breaker trip units. Replace any device that may have
been damaged by the short circuit. For additional
details on a device, refer to the applicable
instruction manual provided with the device.