Emergency power supplies shall be tested how often and for how long?

• A. Every 2 weeks for at least 2 hours
• B. Every week for 1 hour
• C. Every month for 3 hours
• D. Every 3 months for 1 hour

Answer: (A)

Regular testing of emergency power supplies ensures they will function when needed by proving they can start, reach a stable operating state, and deliver the required load. The schedule of every two weeks for at least two hours strikes a practical balance: it keeps equipment exercised often enough to catch developing faults and confirms the system can start, transfer, and run under load for a meaningful period, without overtaxing maintenance resources. Shorter weekly tests of only one hour may not reveal issues that appear after longer runtimes; longer monthly tests of three hours increase the time between checks and risk missing evolving problems; waiting three months with a one-hour test is too infrequent to trust readiness. In practice, the test verifies the automatic start, transfer to emergency power, and sustained operation at load for the duration, confirming both the reliability of controls and the capability of the emergency power source to meet expected demands.