Con Edison Basic Electric Practice Test 2026 – Complete Exam Preparation

Before starting dead work, you must prove that the equipment is truly de-energized by isolating the energy sources and then properly testing to verify there is no voltage at the work point. The reason this is essential is that voltage can still be present even if the device isn’t buzzing or appearing active—stored energy in capacitors or inductive energy, backfeed from another source, or multiple power sources can re-energize things unexpectedly. Using a properly rated, calibrated tester to check for absence of voltage, and confirming the test (often with lockout/tagout in place) before you touch anything, is the only reliable way to ensure safety. Relying on clues like sound, or on someone being nearby, or working energized to “check” if it’s alive, is unsafe and contrary to proper lockout-tagout procedures.