Which of the following is not a basic rule of electrical safety?

The correct choice highlights that working alone is not considered a basic rule of electrical safety. Safety practices in electrical work emphasize the importance of having a partner or colleague present. This approach not only allows for immediate assistance in case of an emergency but also ensures that someone can call for help if necessary.

In contrast, the other options—using insulated tools, checking for voltage before working, and wearing appropriate personal protective equipment—are all fundamental safety measures designed to reduce risk and protect individuals from electrical hazards. Insulated tools help prevent accidental electrical contact, checking for voltage ensures that equipment is de-energized before work begins, and appropriate personal protective equipment, such as gloves and helmets, provides a barrier against electrical shocks and other potential injuries.