Which of the following is a critical safety measure before working on electric circuits?

The critical safety measure before working on electric circuits is de-energizing and locking out equipment. This procedure is essential because it ensures that the circuit is completely free of electrical energy, which significantly reduces the risk of accidental shocks or electrocution while maintenance or repair work is being conducted. Lockout/tagout (LOTO) practices require that all sources of energy be isolated and controlled effectively, safeguarding not only the technician performing the work but also anyone else who might be in the vicinity.

This proactive approach addresses potential hazards by ensuring that no one can inadvertently turn power back on while work is being performed. Effective implementation of de-energizing and locking out equipment is a fundamental principle of electrical safety and is crucial for compliance with safety regulations and standards.

While wearing insulated gloves, turning off the main power supply, and using rubber-soled shoes are also important safety practices, they do not replace the necessity of fully de-energizing and locking out equipment before beginning work on electric circuits.