Critical Site Electrical Testing Requirements for Electrical Contractors

Below we have given few guidelines for electrical testing which can help electrical engineers & electrician to understand what are general requirements for doing the testing & commissioning of electrical systems at any kind of project or facility.

All electrical plants & equipment’s are inspected and tested during and after installation as applicable on site and as set out by the client or consultant in order to comply with the performances, and ratings  described in specifications. The electrical testing is always done by qualified electrician or electrical engineer and should be from reputed electric company / electrical contractors. All portable devices used for testing must be certified via pat testing.

All site tests are witnessed by consultant or client’s representative at site normally with at least seven days’ notice given prior to any test. All tests are executed and, if not satisfactory, repeated to the satisfaction of the client at no extra cost.

Partial Discharge and Ultrasound testing to be done for Medium Voltage Equipment to locate any high dB readings or any partial discharge. The test to be performed by specialist testing engineer and must be completed with conclusive report to record the working condition of the installation and termination etc.


Infrared thermo-electric detection testing to be done for all MV and LV Main Switch Boards, Transformers, variable frequency drives vfd/MCC, Generators and Busducts to locate any hot spot or loose termination. The tests are performed by specialist tester only and completed with conclusive report to record the working condition of the installed equipment or electrical system.

All the tests must be completed at the appropriate stages of the installation, inspection and testing prior to the energizing of equipment i.e. insulation resistance tests shall be made and recorded before energization.

Operational Testing

Operational tests of all electrical equipment in proper staged phases shall be made and recorded prior to energizing. For example, the battery charger and batteries shall be checked prior to furnishing the DC control power for the circuit breakers. The circuit breaker control shall be operationally checked for all local control, including testing up to interface terminal points for signals and control interconnection to other system or installation, prior to carrying out operational tests of the circuit breakers.

Electrical contractor shall develop a complete and detailed plan for the site testing of the power supply systems beginning with the incoming breakers, electrical outlet and electrical switches etc, by following a logical plan which will allow energisation of the system in a safe and secure manner and to interface and co-ordinate with the other electrical and mechanical installations as applicable.