The emergency generator must be run under full load for _____ every ____.

The requirement for an emergency generator to be run under full load for 30 minutes every month is based on best practices for maintaining the generator's readiness and reliability in case of a power failure. Running the generator under load ensures that all components are functioning correctly, helps prevent issues such as fuel degradation, and verifies that the generator can handle the demand when it is needed. This regular testing is crucial for ensuring that emergency power systems are reliable during critical situations.

In the context of the other options, running the generator under full load for shorter durations or less frequently may not provide enough assurance of the equipment's readiness. For instance, a 15-minute test every week may not adequately reflect the generator's capacity to operate under sustained conditions. Similarly, less frequent testing (like annually) or shorter load tests may not provide the necessary conditions to ensure that all components and systems within the generator are functioning optimally. Thus, performing these tests monthly for 30 minutes is an established practice to maintain the reliability and operational readiness of emergency generators.