Wednesday, December 16, 2009

Switchboard installation check

Switchboards are the switching centers of  the low voltage distribution sytem. They are also the places where the control and protection system is located.

Photo 1 - A switchboard being unloaded from the transport at a construction site of a building project

Because of the importance of these equipment, all aspects of a switchboard installation need to be closely monitored. Even the loading and unloading of them to and from the transport need to be monitored.

The following general guide started out as a sample performance specifications for switchboard installations. However, as I tried to make it more detailed, it became more difficult to keep it in a specifications format.

So I decided to just expand it into something like a general guide. I say "general" because I do not want to develop it into a long manual in one go. It will be quite general at this stage, but I will develop it into details using separate short posts for each sub-headings.

As I said, this guide is actually a general checklist of what to monitor and what to inspect. Not everything here need to be followed strictly.

Installation conditions, sequence of work at a particular construction site, and specific arrangement of the  specialist subcontracts etc may make it impractical to follow some of the details in these guide.

It is however the responsibility the supervision personnel to make sure the intention and objectives of the guide are fulfilled, whichever way they are achieved.

Switchboard installation checklist:

A. Preparation of the switchboard room
1) Coordinate with other trade contractors to ensure that the floor of the switchboard room is sufficiently level.

2) The electricity supply for lighting, small power and mechanical ventilation shall be provided as provided for in the construction drawings. Prior to commissioning of the switchboard, the lighting and (if required) the mechanical ventilation works should be completed and tested.

3) If an active fire protection system is required in the
switchroom, the installation should be completed and properly tested before the switchboard can be commissioned.

4) The foundation channels for the switchboard should be installed flushed with the floor.

5) Once the switchboard is located in the room, all entrances should be secured by padlocking all the doors. This should be done regardless whether the installation of the switchboard is completed or not. This measure need to be taken not just for the security of the equipment, but also to prevent any possibility of unathorized tampering of the equipment and components of the switchboard.

B. Cleanliness of the room

1) Prior to the commencement of a switchboard installation work, check to make sure that the room where the switchboard will be installed is free from construction debris.

2) If further "dirty works" (such as hacking of concrete walls to relocate a mechanical ventilation fan) need to be carried out after the switchboard is in place, sufficient precaution should be taken to protect the board from dusts and falling debris.

C. Readiness of the switchboard and other equipment

1) Preferably at this point of time all cable ladders,  HV cables, LV cables and control cables should have been properly installed in the switchboard room and ready for connection to the switchboards, the motor starter panels and the auto transfer switches.

2) Install the switchboard, the motor starter panels and the automatic transfer switches in accordance with the contract specifications, the manufacturer’s instructions and within the designated switchroom as shown in the design drawings.

3) Position and secure the mounting bolts for each of the switchboard and motor starter panels on the foundation channel according to manufacturer’s recommendations. All panels shall be installed level and plumb. The front of all panels shall be lined up and present a neat and orderly appearance.

4) During installation of main busbars and the earthing busbar, make sure that the joint surfaces are clean before tightening the bolts. All bolts used shall be of appropriate size.

5) Permanent phase identification shall be provided on the exterior of the enclosures, and they shall match the busbar phase identification inside the enclosures.

6) Connect the signal cables from each lift motor room to the auxiliary signal contacts of the automatic transfer switch (closed before switch returns to normal power). The termination work shall be done by the lift vendor under the supervision of the electrical sub-contractor.

7)  Connect the signal cables from engine start contacts of the standby generator panel to the auxiliary signal contacts of the automatic transfer switch.

8) Test the racking in and racking out of all withdrawable circuit breakers. Check and adjust the alignment. Check the alignment of all auxiliary contacts.

9) After re-assembling all switchboard panels, check all inter-panel wiring, power and control wiring prior to commencement of the pre-commissioning tests. Unless prohibited by the arrangement of the sub-contract packages, re-assembly of the switchboard panels and inter-panel wiring at the construction site shall be carried out by the switchboard manufacturer.

10) Upon completion of the installation, terminate all control cables, power cables and busducts to the respective terminals.

11) Replace all switchboard and starter panel covers and prepare for pre-commissioning checks.

12) Perform all inspections and tests as prescribed in the the pre-commissioning tests section.

13) Certify that all the required tests have been performed and that the switchboards and the motor starter panels are performing in accordance with the contract specifications.

14) Seal all the rear and top panels of the switchboards, the motor starter panels and the automatic transfer switch units using methods prescribed in the specifications or approved by the Electrical Inspector.

15) All installation procedures shall follow manufacturer’s recommendation wherever applicable.

16) Test all protection relays. This task shall be carried out by a Licensed Testing Contractor approved by the appropriate authority. The testing results, certificates and  all relay coordination curves shall be filed for incorporation into the Operation and Maintenance Manual.

17) Records of the installation works shall be properly kept and submitted to the Employer’s Representative.

18) During termination of cables, ensure that all surfaces are clean before tightening the bolts and cable lugs.

19) Padlock all circuit breakers in the OFF position and keep keys in the lockable cabinet.

20) Carry out the touch-up work on all damaged paintwork of the switchboard and motor starter panels. All surfaces shall be properly cleaned prior to commissioning.

D. Cable installation and termination

1) All power cable installation works shall be carried out after studying and coordinating the recommendations of the cable manufacturer, and the manufacturers of the switchboard, the motor starter panels and the automatic transfer switch unit.

2) Busbar cable termination and units shall be installed on the switchboards at the manufacturer’s works, with busbar connection to the termination and the unit.

E. Packing, transport and handling

1) All switchboards, motor starter panels and automatic transfer switches shall be packed and delivered with appropriate labels as recommended by the manufacturer.

2) The  labels shall be as shown in the contract drawings for easy identification at site.

3) All interconnecting busbars, earth bars, and insulation material or components, etc shall be packed separately. The packing shall be properly secured to prevent any movement or damage during transportation.

4) Measures should also be taken to prevent damage or deterioration of the components and equipment due to tropical climatic conditions or other weather related effects encountered during shipment.

5) Lifting eyes shall be provided to facilitate lifting. The manufacturer shall provide all necessary information for unpacking and lifting safely, including details of any special lifting and positioning devices, whenever necessary.

6) Each switchboard, motor starter panels and automatic transfer switch shall be supplied complete with:

Foundation channels
Foundation bolts
Interconnecting busbars and insulation materials, etc

F.  Storage at the construction site
1) On arrival at site, the consignments shall be checked against the delivery notes. (Note: There are cases where a shipmet for one project are sent to a different project due to error by the delivery truck, especially if there are a number of different construction projects running concurrently near to each other.)

2) Upon arrival at site, the switchboards and motor starter panels shall be stored indoor in a clean, dry and appropriately ventilated place. For prolonged storage, the panel anti-condensation heaters may have to be switched on to prevent moisture condensation and consequent damage and mal-operation.

Note: This anchor post, Free electric installation pictures , may contain a summary of the materials you are looking for. It can be faster than clicking through each post title at the Blog Archive. I started it long ago but never actually got around to finish it.

Copyright Switchboard installation check


Madeleine Clark said...

Nice to hear that from you.This blog is profitable and instructive to all of us.Thanks for sharing those guidelines about installing switchboard,that is a big favor to those people who not yet known about this.

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row anco said...

Appreciation for the great text. I am just glad Concerning taken any time to know this.electrical switchboard manufacturing

Boon Electrical said...

Great switchboard installation checklist, it is very helpful for guys like us who is willing to hire electricians. It is advisable that we also know some of their job role which can be helpful. Thanks for sharing this useful post with us. Also I would like to share best commercial electrical contractors who are experts in switchboard installtion at affordable price.