Checking and Testing
On completion of the electrical work and before the electricity supply is connected and energised, the electrical contractor is responsible to ensure that:
the electrical work has been carried out in accordance with the Electricity (Licensing) Regulations 1991; and
the installation has been checked and tested and is safe for connection to the electricity supply.
To achieve this, the following minimum checks and tests should be carried out by the electrician:
1. Visual Inspection – should be carried out whilst referring to a plan (to ensure a systematic check to pick up any omissions and to verify that the work complies with the requirements of the applicable standards).
2. Earth Resistance and Continuity Tests – this test is to include the main earthing conductor, protective earth conductor and bonding conductor.
3. Insulation Resistance Test – this test is necessary to ensure that the insulation resistance between live parts/conductors and earth is adequate.
4. Polarity Test – used to ensure correct connection of active, neutral and earthing conductors.
5. Correct circuit connections – this test checks earthing conductors do not carry current during normal operation and no short circuit exists.
6. Fault Loop Impedance – measures the fault loop impedance of each circuit to verify the protective device will operate.
7. Verification of RCD (residual current device) operation – testing of RCDs is carried out to ensure that the RCD operates.