What precaution should be taken before working on a rectifier?

Before working on a rectifier, it is crucial to take safety precautions to protect against electrical hazards. The practice of measuring a case-to-ground voltage or using an instrument that detects AC voltage is essential because it ensures that the equipment is not live or poses an electrocution risk. This precaution allows the technician to confirm whether there is any lingering AC voltage present, which could otherwise lead to severe electrical shocks during maintenance or repairs.

Utilizing instruments specifically designed to detect AC voltage provides a reliable means of assessing electrical safety. This step helps in establishing a safe working environment, allowing personnel to perform their tasks without the risk of encountering unexpected live components. It emphasizes the importance of adhering to safety regulations and standards in electrical work, ensuring that all potential hazards are identified and mitigated before any maintenance activity begins.