Which of the following is a common duty of a security guard?

Monitoring surveillance equipment is a fundamental duty of a security guard. This task involves observing live feeds from cameras to identify any suspicious activities or security breaches in real-time. By keeping an eye on these recordings, security guards play a critical role in deterring crime and maintaining safety within a facility or a designated area.

The importance of this duty cannot be overstated, as effective surveillance can prevent incidents before they escalate and ensure quick responses to emergencies. Additionally, the information gathered from monitoring may serve as valuable evidence in case of an investigation following an incident.

Other options like performing electrical maintenance, preparing financial reports, and planning corporate events, while essential in their respective fields, do not typically fall within the scope of a security guard's responsibilities. These tasks are more specialized and are usually handled by trained professionals in those areas.