Shell - Chennai
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Date: 3rd & 4th Dec 09. Shell Shared Services Center – Phase-2 at RMZ Millenia Electrical system audit report 1) Preamble Shell India has occupied a complete tower at RMZ millennia, Chennai. The tower contains G+10 floors with two levels of basements. The two basements, Ground & 1st floor is under battery limit of developer (RMZ). The projects have been executed in two phase, 1 & 2. 1st phase covers 2nd, 3rd, 4th & UPS room of 5th floor was handed over in mid Feb. 2 nd phase comprising of complete 5th, 6th & 7th floor was handed over in end Sep. Shell have occupied 5th & 6th floors but 7th floor is yet to be occupied. Key areas pertaining to electrical system in phase-2 is 5 th floor UPS room, 6th & 7th floor north & south wing electrical rooms. Typical North electrical room contains, •
Lighting panel
•
UPS panel
•
Raw power panel
•
Raw power DB
•
Lighting DB
•
VAV DB
•
Emergency lighting DB
Typical South wing electrical room contains, •
Lighting DB
•
Raw power DB
•
UPS panel
2) Observations on quality and remedial measures. Page 1 of 17
The following observations noticed during the facility walk through,
Observation The panels have common bus for neutral & earthing. From the electrical shaft two runs of neutral & earthing have been derived but at the same time these two cable are not seem to be connected to the dedicated earth & neutral buses
Consequence
Remedial action
This can cause point failure for neutral & earting also over rules the concept of double neutral & earthing
Have to be re-checked & confirmed that both the runs of neutral & earthing have been connected to specific busses via two separate bolt nuts
Page 2 of 17
Observation
Consequence
Remedial action
Identification of BMS cable should be done
Facility may not be aware of the purpose of this cable hence can create confusion in future
Cable tags to be provided mentioning type of cable & from where it is been derived from
Page 3 of 17
Observation
Consequence
Remedial action
Multiple earthing & neutral connections have been done via single bolt nut
In case of loose contact in this bolt, all the circuits connected to this bolt nut will be cut-off
Neutral & earthing busses to have more provisions to connect earthing & neutral separately for separate circuits
Page 4 of 17
Observation
Consequence
Calibration of energy meters.
Without meters been calibrated, the readings of the meter will not be reliable & can create panic during future maintenance
Remedial action The present calibrated energy meters to have stickers mentioning the next calibration date. Electrical panel vendor to stick stickers mentioning the next calibration date. Also to be consolidate in an excel sheet & shared with facility team.
Page 5 of 17
Observation
VAV DB & ELDB
Consequence For easy identification & rectification of any problem, the main breaker should have stickering mentioning the type cable & source of power to these breakers
Remedial action
Stickering to be done
Page 6 of 17
Observation
Consequence
Type & Connection of main neutral link in UPS SMSBs
Loose connection in neutral can cause cable melting & disconnection of main neutral to the panel. The entire wing which has been fed by this panel will be on risk
Remedial action I have a serious doubt on the neutral link used, there is a slot on the link which reduces the conductive area of the link. To be cross checked with consultants & probably at-least two links to be used for each cable to compensate for the required conductive area. Also, main neutral link to be fastened properly with washers, bolt nuts to be rechecked for tightness. Per the drawing from consultants two separate set of neutral links to be used. The same has to be incorporated.
Page 7 of 17
Observation
Consequence
Remedial action
Finishing of Panel base frame
Rusting of base frame
Base frames to be finished with a coat of primer & paint
Page 8 of 17
Observation
Consequence
Remedial action
Maintenance of terminations
Loose contact can create burning of cable & disconnection of links
All terminations to be checked & tightened regularly
Page 9 of 17
Observation
Installed shock treatment chart & First aid boxes are missing in some of the electrical rooms
Consequence
Remedial action
For safety & authority requirement
Shock treatment chart & First aid boxes to be installed in all electrical rooms
Page 10 of 17
Observation
Neutral connection from main incomer
Consequence Bolting of two neutral connections together over rules the fact of double/ redundant neutral concept. Failure in this one particular bolt disconnects both neutrals together
Remedial action
Neutral cables to be terminated at two different locations with separate bolt nut & washer.
Page 11 of 17
Observation
Panel body earthing
Consequence Improper body earthing can create disconnection of earthing & can result dangerous for the maintenance team
Remedial action
Body earthing to be terminated properly.
Page 12 of 17
Observation
Consequence
Remedial action
Insulation & Identification of earth strips
Avoids unwanted connection to dedicated earthing provided for UPS sources
Earth strips to be properly stickered at least floor wise & to be properly insulated where ever stripped off for connection.
Page 13 of 17
Observation
Consequence
Remedial action
Socket termination at field end
Improper termination can cause tripping of breakers.
All sockets to be checked for termination using lugs & feruled.
Page 14 of 17
Observation Earth pits
Consequence Loss of earth connectivity can cause serious accidents for machines & worker operating
Remedial action The earth pits which were part of Phase-1 has not been maintained properly, it is hard to find the funnel set itself. Since all critical equipments are earthed to these pits these needs to be Page 15 of 17
maintained properly. This is a very serious concern & need to be intimated to client immediately.
observation
Consequence
System discrimination to be set
Improper breaker discrimination can cause nuisance tripping of main breakers & subsequently UPS
In 7th floor north side electrical room water leaking is observed in electrical room
Chances of water entering into the raising main will create tripping & heating of raising mains
reference. This is a serious issue because if water seeps inside the raising main it takes days to get dried & we may end up with no lighting & RP supply for weeks. The shaft to be made water tight immediately.
Not major
All unwanted materials to be removed from the panels & to be cleaned with blowers.
Should b e 4 sqmm as per the drawings
Need to be changed as 4 sqmm
Cleaning of panels
Remedial action Electrical consultants should provide breaker discrimination from the main source of electricity till the DB breaker. A sample of discrimination study is attached at the end for Discrimination study.zip
Raw Power Circuits 7 nos in 5th of circuits done with 2.5 Sqmm wire
Page 16 of 17
Some of the observations in asbuilt drawings, 1) Some modifications have been done in existing UPS panel of 5th floor, this has to be incorporated in the as-built drawing. 2) As built drawing of UPS SMSB shows two neutral link for main & sub breakers but per the site it is not. To be checked. 3) As built drawing wrongly shows 4R x 16 Sqmm as coming cable to UPS SMSB, it should be 5R x 35 Sqmm 4) 80A breaker shown as SMSB incomer but actual is 100A 5) UPS SLD shows 2 pole ELMCB as sub breaker but actually it is DP MCB 6) Lighting SLD shows 3.5c x 25 Sqmm incoming cable actual is 4c x 25 Sqmm 7) Incomer for VAV DB is 4c x 10 sqmm actual is 4R x 16 Sqmm 8) VAV DB incomer to be changed in as built 9) VAV DB doesn’t have DP MCB to be changed in as built
Difficult to maintain & attend to faults
To be revised & resubmitted
Page 17 of 17
Lighting panel
•
UPS panel
•
Raw power panel
•
Raw power DB
•
Lighting DB
•
VAV DB
•
Emergency lighting DB
Typical South wing electrical room contains, •
Lighting DB
•
Raw power DB
•
UPS panel
2) Observations on quality and remedial measures. Page 1 of 17
The following observations noticed during the facility walk through,
Observation The panels have common bus for neutral & earthing. From the electrical shaft two runs of neutral & earthing have been derived but at the same time these two cable are not seem to be connected to the dedicated earth & neutral buses
Consequence
Remedial action
This can cause point failure for neutral & earting also over rules the concept of double neutral & earthing
Have to be re-checked & confirmed that both the runs of neutral & earthing have been connected to specific busses via two separate bolt nuts
Page 2 of 17
Observation
Consequence
Remedial action
Identification of BMS cable should be done
Facility may not be aware of the purpose of this cable hence can create confusion in future
Cable tags to be provided mentioning type of cable & from where it is been derived from
Page 3 of 17
Observation
Consequence
Remedial action
Multiple earthing & neutral connections have been done via single bolt nut
In case of loose contact in this bolt, all the circuits connected to this bolt nut will be cut-off
Neutral & earthing busses to have more provisions to connect earthing & neutral separately for separate circuits
Page 4 of 17
Observation
Consequence
Calibration of energy meters.
Without meters been calibrated, the readings of the meter will not be reliable & can create panic during future maintenance
Remedial action The present calibrated energy meters to have stickers mentioning the next calibration date. Electrical panel vendor to stick stickers mentioning the next calibration date. Also to be consolidate in an excel sheet & shared with facility team.
Page 5 of 17
Observation
VAV DB & ELDB
Consequence For easy identification & rectification of any problem, the main breaker should have stickering mentioning the type cable & source of power to these breakers
Remedial action
Stickering to be done
Page 6 of 17
Observation
Consequence
Type & Connection of main neutral link in UPS SMSBs
Loose connection in neutral can cause cable melting & disconnection of main neutral to the panel. The entire wing which has been fed by this panel will be on risk
Remedial action I have a serious doubt on the neutral link used, there is a slot on the link which reduces the conductive area of the link. To be cross checked with consultants & probably at-least two links to be used for each cable to compensate for the required conductive area. Also, main neutral link to be fastened properly with washers, bolt nuts to be rechecked for tightness. Per the drawing from consultants two separate set of neutral links to be used. The same has to be incorporated.
Page 7 of 17
Observation
Consequence
Remedial action
Finishing of Panel base frame
Rusting of base frame
Base frames to be finished with a coat of primer & paint
Page 8 of 17
Observation
Consequence
Remedial action
Maintenance of terminations
Loose contact can create burning of cable & disconnection of links
All terminations to be checked & tightened regularly
Page 9 of 17
Observation
Installed shock treatment chart & First aid boxes are missing in some of the electrical rooms
Consequence
Remedial action
For safety & authority requirement
Shock treatment chart & First aid boxes to be installed in all electrical rooms
Page 10 of 17
Observation
Neutral connection from main incomer
Consequence Bolting of two neutral connections together over rules the fact of double/ redundant neutral concept. Failure in this one particular bolt disconnects both neutrals together
Remedial action
Neutral cables to be terminated at two different locations with separate bolt nut & washer.
Page 11 of 17
Observation
Panel body earthing
Consequence Improper body earthing can create disconnection of earthing & can result dangerous for the maintenance team
Remedial action
Body earthing to be terminated properly.
Page 12 of 17
Observation
Consequence
Remedial action
Insulation & Identification of earth strips
Avoids unwanted connection to dedicated earthing provided for UPS sources
Earth strips to be properly stickered at least floor wise & to be properly insulated where ever stripped off for connection.
Page 13 of 17
Observation
Consequence
Remedial action
Socket termination at field end
Improper termination can cause tripping of breakers.
All sockets to be checked for termination using lugs & feruled.
Page 14 of 17
Observation Earth pits
Consequence Loss of earth connectivity can cause serious accidents for machines & worker operating
Remedial action The earth pits which were part of Phase-1 has not been maintained properly, it is hard to find the funnel set itself. Since all critical equipments are earthed to these pits these needs to be Page 15 of 17
maintained properly. This is a very serious concern & need to be intimated to client immediately.
observation
Consequence
System discrimination to be set
Improper breaker discrimination can cause nuisance tripping of main breakers & subsequently UPS
In 7th floor north side electrical room water leaking is observed in electrical room
Chances of water entering into the raising main will create tripping & heating of raising mains
reference. This is a serious issue because if water seeps inside the raising main it takes days to get dried & we may end up with no lighting & RP supply for weeks. The shaft to be made water tight immediately.
Not major
All unwanted materials to be removed from the panels & to be cleaned with blowers.
Should b e 4 sqmm as per the drawings
Need to be changed as 4 sqmm
Cleaning of panels
Remedial action Electrical consultants should provide breaker discrimination from the main source of electricity till the DB breaker. A sample of discrimination study is attached at the end for Discrimination study.zip
Raw Power Circuits 7 nos in 5th of circuits done with 2.5 Sqmm wire
Page 16 of 17
Some of the observations in asbuilt drawings, 1) Some modifications have been done in existing UPS panel of 5th floor, this has to be incorporated in the as-built drawing. 2) As built drawing of UPS SMSB shows two neutral link for main & sub breakers but per the site it is not. To be checked. 3) As built drawing wrongly shows 4R x 16 Sqmm as coming cable to UPS SMSB, it should be 5R x 35 Sqmm 4) 80A breaker shown as SMSB incomer but actual is 100A 5) UPS SLD shows 2 pole ELMCB as sub breaker but actually it is DP MCB 6) Lighting SLD shows 3.5c x 25 Sqmm incoming cable actual is 4c x 25 Sqmm 7) Incomer for VAV DB is 4c x 10 sqmm actual is 4R x 16 Sqmm 8) VAV DB incomer to be changed in as built 9) VAV DB doesn’t have DP MCB to be changed in as built
Difficult to maintain & attend to faults
To be revised & resubmitted
Page 17 of 17
