Before using a megger to check an in-service cable, what must the electrician ensure?

The correct answer emphasizes the importance of safety by ensuring that the cable is de-energized and properly locked and tagged out before using a megger. A megger, which tests insulation resistance, applies a high voltage to the cable to measure how well the insulation is performing. If the cable is still energized, applying this test can damage the equipment, cause inaccurate readings, or pose serious safety hazards to the electrician.

De-energizing the cable not only protects the equipment but also safeguards the technician from electrical shock or injury. The lockout/tagout protocol is a critical practice in electrical work, ensuring that no one can accidentally restore power while the technician is performing tests. Proper procedures must be followed for any maintenance or testing to comply with safety regulations and industry standards. This preparation is essential before proceeding with any testing to ensure a safe working environment.