Testing and Commissioning In Electrical Construction Works





At the completion of the electrical installation works, the entire installation shall be subject to the test before final placing in service under the full responsibility of the contractor. Unless Otherwise specifically called for all tests shall be carried out in conformity with IEE regulations. Contractor shall coordinate with the Client and the Supervising Engineer to get electricity from the local supply authority before starting of testing and commissioning.

Insulation Megger Testing

For any reason, if there is any delay in getting the power supply contractor shall either make his own temporary arrangement to test all the equipment or to give undertaking to test and commission the equipments as and when supply available without any extra cost. The virtual completion of work can be accepted from the date of handing over after completing the successful testing and commissioning procedure.

Kinds of Electrical Installation Testing

Following tests shall be carried out: Wiring continuity test, Insulation resistance test, Earth continuity test, Earth resistivity test, Performance test, and any other tests as instructed by the Supervising Engineer.

1. Electrical Wiring Continuity Testing

All wiring system shall be tested for continuity of circuits, short circuits and earthing after wiring is completed and before energizing.

2. Electrical Insulation Resistance Testing

The insulation resistance shall be measured across earth and the whole system of conductors, or any section thereof, with all fuses in place and all switches closed and except in concentric wiring all lamps in position of both poles of the installation otherwise electrically connected together.

A direct current pressure of not less than twice the working pressure provided that it does not exceed 660 V for medium voltage circuits. Where the supply is divided from AC three phase system, the neutral pole of which is connected to earth, either direct or through added resistance, pressure shall be deemed to be that which is maintained between the phase conductor and the neutral.

The insulation resistance measured as above shall not be less than 50 mega ohms divided by the number of points on the circuit provided that the whole installation, shall not be required to have an insulation resistance greater than one mega ohm.

Electrical Insulation Megger testing for Electrical Machines and Panel Boards

The insulation resistance shall also be measured between all conductors connected to one phase conductor of the supply and all the conductors connected to the middle wire to the neutral or to the other phase conductors to the supply. Such a test shall be carried out after removing all metallic connections between the two poles of the installation and in these circumstances the insulation shall not be less than that specified above.

The insulation resistance between the case or frame work of housing and power appliances, and all live parts of each appliance shall not be less than that specified in the relevant British standard specification or where there is no such specification shall not be less than a mega ohm.

3. Electrical Earth Continuity Path Testing

The earth continuity conductor metallic envelops of cables, shall be tested for electric continuity and the electrical resistance of the same along with the earthing lead but excluding any added resistance or earth leakage circuit breaker measured from the connection with the earth electrode to any point in the earth continuity conductor in the completed installation shall not exceed one ohm.

4. Electrical Testing of Non-linked Single Pole Switches

In a two wire installation a test shall be made to verify that all non linked single pole switches have been fitted in the same conductor throughout, and such conductor shall be labeled or marked for connection, throughout, and such conductor shall be labeled or marked for connection to an outer or phase conductor or non earthed conductor a test shall be made three or four wire installation a test shall be made to verify that every non linked single pole switch is fitted in a conductor to one of the outer or phase conductor of the supply. The entire electrical installation shall be subject to the final acceptance of the Supervising engineer as well as the local authorities.

5. Electrical Earth Resistivity Testing

Earth resistivity test shall be carried out in accordance with British Standard Code of Practice of Earthing. All tests shall be carried out in the presence of the Supervising Engineer.

6. Electrical Performance Testing

The complete electrical installation and equipment shall be subject to the final performance test as intended for each and every equipment shall be tested as per the manufacturers instructions.

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