|Electricals & Electronics
|Power Distribution Solutions
17
14. ENERGIZING
Before Energizing
14.1.
Recheck all joint connections for tightness by following on the recommended torque value given as section
13.3. Table 2. Ensure that outer head of MF nut is broken. If not, then retighten the nut until it is broken, before
installing side cover.
14.2.
Ensure that upper nuts are of the spring hangers are unscrewed 15mm above the upper part of spring hanger.
14.3.
Isolate the busduct run by disconnecting all connections to transformers, switchboards, meters and so forth.
14.4.
Conduct an insulation resistance test on the whole busduct connection after installation. The insulation
resistance value cannot be specified due to the length of the route and the environmental factors. In a dried
atmosphere, it would give a value of approximately 5
MΩ, it has to be checked due to some factors that can
reduce the insulation and the other factors can be as follows;
14.4.1.
Whether the busduct is damaged.
14.4.2.
Whether the connecting parts are fixed precisely.
14.4.3.
Whether the bolts for connecting the equipment are securely fastened.
14.4.4.
Whether the hangers are supporting the busduct securely.
14.4.5.
Whether the vertical spring hanger is properly.
14.4.6.
Busduct kept idle without charging for a very long period of time in humid atmosphere / conditions.
After energizing
When the equipment is energized for the first time,
competent and qualified
electrical personal
should be
present.
If short circuits and ground faults caused by damage or poor installation practices have not been
detected in the check-out procedure, serious damage can result when the power is turned on.
14.5.
There should be no electrical load on the busduct when it is energized. Since busduct typically extends through
several rooms and floor levels, care should be taken to see that all devices fed from the busduct are in the
“OFF” position.
14.6.
The equipment should be energized in sequence by starting at the source end of the system and working
towards the load end. In other words, energize the main devices, then the feeder devices and then the branch-
circuit device
s. Turn the devices to the “ON” position with a firm positive motion.
14.7.
After all over-current devices have been turned on, loads such as lighting circuits, contractors, heaters, and
motors may be turned “ON”.
14.8.
Busduct, when operating properly, will have a moderate hum. Excessive noise may be an indication of
hardware that has not been tightened or of metal parts that have been improperly assembled.
14.9.
Occurrence of sparking at any point along the busduct is not a normal condition. The busduct must be de-
energized immediately, and remain de-energized until the sparking condition has been corrected.
15. CARE AND MAINTENANCE
15.1.
OUTDOOR BUSDUCT
15.1.1.
Inspect busduct once each year or after any severe electrical short circuit or ground fault.
15.1.2.
Perform an infra-red temperature scan on all electrical connections and busduct enclosure while
busduct is energized and operating under maximum load conditions. A permanent record should be
kept. If readings change with time, deterioration may be taking place and must be corrected.
15.1.3.
Turn off power to the busduct.
15.1.4.
If there is appreciable accumulation of dust and dirt, clean it off by using a brush, vacuum cleaner, or
clean lint-free rags. In order to avoid blowing dust into busduct joint, circuit breakers, or other
equipment, do not use a blower or compressed air. Ensure that all drain holes are operating properly.
15.1.5.
Check the insulation resistance prior to re-energizing the busduct. A permanent record should be kept
of resistance readings. If readings decrease appreciably with time, deterioration is taking place and
must be corrected (contact the manufacturer).