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List of Functional Tests Required for Electrical Systems

MS Chaudhry

Electrical functional testing is very important and critical part of any electrical project.

Most of the times it is necessary to hire a third party in order to conduct the function testing of electrical systems.

Big electromechanical companies are having their own testing and commissioning teams that can perform the electrical tests depending upon the client agreement and approval.

Functional test for the electrical system shall be conducted for performance, safety, reliability, maintainability and for compliance with the specified requirements.

Testing and commissioning of electrical equipment shall be performed progressively on site in accordance with the contract program to verify that the complete installation will meet the requirement of the project electrical specifications.

The list provided below is an indicative minimum of the electrical tests required.

Site electrical engineer shall develop full test schedules for approval in accordance with the requirements as described in respective sections of the specific project electrical testing and commissioning specifications.

Below is list of different functional tests that are not fully covering a single project instead can be useful for reference only.

Each project or building will have its own requirements based upon applicable local electricity regulations.

General Checks & Inspections 

    1. Check correct CT ratio and polarity and correct operation of all protective gear by primary tests and system fault tests to check sensitivity and stability.
    2. Secondary current injection tests for accuracy of relay operations. Protective gear timing tests as may be necessary.
    3. Rotational tests on all motors.
    4. Battery tests on specific gravity, correct output voltage, discharge test and proper functioning of the charging equipment etc.
    5. Tests to prove correct operation of all interlocks, tripping and closing circuits, alarm indications, etc. including operation in conjunction with the standby generator for emergency operation of lofts, etc.
    6. Phasing tests.

Tests for MV Switch Board, Transformer, and MV Cable

    1. Injection Test (Primary ad Secondary)
    2. Insulation Test
    3. Partial Discharge and Ultrasound Test
    4. Infrared Thermoelectric Detection
    5. Manufacturer Recommended Test

Testing of LV Switchboard

    1. Mechanical tests
    2. Continuity and dielectric tests
    3. Secondary injection test to re-calibrate all measuring, protect and control circuits and associated components
    4. Phase sequence tests on each outgoing units
    5. Functional checks, especially on the controlling devices
    6. Infrared Thermoelectric Detection (include power factor correction equipment)
    7. Primary Injection Test

Testing Of Cables

    1. Continuity test
    2. Insulation resistance test and
    3. Phasing test

Standby Diesel Generator / Generating Plant

    1. Series of test starts and checks on ability to take up the load within the specified time
    2. Check that speed variation is within specified limits
    3. Voltage regulation test
    4. Functional tests of all plant protection features and alarms
    5. Temperature rise test
    6. Noise level measurement
    7. Insulation resistance test
    8. Building essential load test and
    9. Infrared Thermoelectric Detection.

Hydraulic Tests

    1. Hydraulic test of 70 kPa for bulk tank for not less than 2 hours.
    2. Hydraulic test of 70 kPa for pipe works, valves and fittings for not less than 2 hours.

Testing of LV Power Distribution System

The following items, where relevant, shall be tested in the sequence indicated:

    1. Continuity of ring final circuit conductors
    2. Continuity of protective conductors, including main and supplementary equipment bonding
    3. Earth electrode resistance
    4. Insulation resistance
    5. Insulation of site-built assemblies
    6. Protection by electrical separation
    7. Polarity
    8. Earth fault loop impedance
    9. Function of all items of equipment and
    10. Infrared Thermoelectric Detection

Download Electrical Testing and Commissioning Method Statements

Lighting Testing Requirements

    1. Illuminance / luminance measurements for normal, emergency and battery lightings
    2. Illuminance / luminance measurement for battery lights at the end of 2-hour operation
    3. Test to establish correct operation of switching control
    4. Insulation resistance tests to earth and between conductors before and after fitting of lamps
    5. Measurement of leakage current when directed by the Contractor.

Testing Lightning Protection System

    1. Continuity between air and Foundation earth; and
    2. Foundation Earthing

Testing of Uninterruptible Power Supply UPS

    1. Full Test to Manufacturer Recommended Procedures
    2. Full load test to verify the total back-up time
    3. Infrared Thermoelectric Detection
    4. Ultrasound Test
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