What is the typical sequence for testing a new installation before energisation?

• A. Verify drawings, inspect installation, insulation resistance test, earth continuity test, polarity check, continuity of bonding, set protective devices, and energise with supervision
• B. Visual inspection only
• C. Verify drawings, inspect installation, insulation resistance test, earth continuity test, polarity check
• D. Energise first to test operation

Answer: (C)

Testing a new installation before energisation focuses on confirming safety and integrity through a non-energised sequence. Start by verifying the drawings to ensure the installed work matches the design, ratings, and protective arrangements. A careful visual inspection then follows to spot issues like incorrect terminations, damaged insulation, or routing problems before any testing. The insulation resistance test checks the integrity of all insulation by applying a high DC voltage and measuring resistance; a high, stable value indicates good insulation, while low values point to faults or moisture that could cause leakage or faults once powered. Next, the earth continuity test verifies that the protective earth path from exposed metalwork back to the origin is continuous and has a low enough resistance to ensure a fault current will trip protective devices promptly. Finally, the polarity check confirms that live, neutral, and earth connections are correctly identified and connected, preventing shock or incorrect operation of equipment. Energising and final adjustments are carried out later under supervision, once these pre-energisation checks have confirmed the installation meets safety and design requirements.