What is the recommended practice when performing insulation resistance tests on energized equipment?

• A. De-energize and isolate circuits; use hot-stick and proper PPE; follow test voltage limits and safety rules
• B. Test with the equipment energized to verify live readings
• C. Ignore PPE to speed up testing
• D. Increase test voltage beyond rating to ensure accuracy

Answer: (A)

When performing insulation resistance tests, you must de-energize and isolate the equipment, operate switches remotely with a hot-stick, wear proper PPE, and follow the test voltages and safety rules. Testing insulation while the system is live can create shock and arc-flash hazards, and it can damage insulation or produce misleading readings since the live circuits influence the measurement. By removing power and isolating the circuit, you’re measuring the true leakage resistance of the insulation without interference from energized parts. Using a hot-stick lets you control disconnects and barriers from a safe distance, reducing your exposure, while the right PPE protects you from potential shocks or arc events. It’s also essential to stay within the voltage limits specified for both the insulation and the tester, because applying too high a voltage can break down insulation or skew results. Before connecting the tester, ensure capacitors are discharged and the circuit remains de-energized during the test. This approach prioritizes safety and accuracy, which is why it’s the recommended practice.