The purpose of this method statement procedure is to define the step by step method to guide & implement the correct practices for the precommissioning & commissioning of Distribution Boards or DB’s.
Through the guidelines contained herein so as to ensure that the job execution complies with the project requirements and serves the intended design function to satisfactory level.
Required Tools / Instruments
- Portable Hand tools
- Step Ladder
- ELCB Tester
- Insulation Resistance Tester
Precommissioning Procedure for Distribution Board
- Ensure that the Distribution Board installation is complete and all mechanical & electrical comments on installation ITRs are completed & approved.
- Ensure that no damage has occured between mechanical completion & precommissioning.
- Repair / replace damaged components, if any.
- Ensure that the DB are properly tagged & identified location wise and service wise.
- Check & record insulation resistance values of all outgoing circuits.
- Ensure that the wiring termination to the Distribution Board are complete & are tight & secure.
- Ensure that the outgoing cables from the power DB are terminated in the respective equipment, power socket, spur outlets, etc,
- Ensure the polarity & the ring circuits are tested for proper installation.
- Ensure that the outgoing cables from the lighting DB are terminated in all light fittings.
- Ensure that the earthing of the DB has been completed.
- Check for proper location & mounting height of the DBs for proper access.
- Ensure that the incoming cables to the DBs are properly installed and terminated.
- Ensure that the cables to the DB are properly tagged & identified.
- Ensure that the rating of the incoming & outgoing breakers (MCBs, ELCBs) are as per approved shop drawings & schedules.
- Check manual operation of all the breakers in the DB.
Commissioning Method/Procedure for Distribution Board
- Ensure that all the precommissioning checks are carried out successfully.
- The incoming supply of the Distribution Board shall be measured for current & voltage.
- The outgoing feeders shall be energised one by one & check for healthiness.
- Check the earth leakage trip setting.
- Check the incomer trip setting.
- Check the circuit breakers on/off function.
Test on ELCB Tripping for socket circuits
- Connect the test lead of ELCB digital tester with a three pin plug connected as follows:BROWN to PHASE, BLUE to NEUTRAL, YELLOW/GREEN to EARTH.
- Plug the testing instrument into the socket outlet that is protected by ELCB to be tested & turn breaker switch ON.
- Set trip current range switch position to rated trip current of ELCB under test.
- To verify the correct wiring light glows in P-N & P-E in the ELCB tester, set the fucntion switch to trip in the ELCB tester.
- Press Test button. Breaker trips with all neon lamps extinguished & the breaker trip time will be displayed.
- Release the Test button. Change 0 deg. / 180 deg.selector position and press Test button. Breaker trips with all neon lamps extinguished. Breaker trip time will be displayed.
- The reading is displayed only while the press to Test button is held down. It will display the result for approximately 10 seconds before changing.
- Precommissioning check sheet for DB’s
- Commissioning check sheet for DB’s
- Risk Assesment
- Manufacturer’s instructions
- Precommissioning & Commissioning Plan for Electrical Systems