What three-phase, four-wire system does the Air Force permit for use in medical facilities?

The correct answer is Wye-powered, which refers to a three-phase, four-wire electrical system. In this configuration, three phase conductors and a neutral conductor are utilized, facilitating balanced loads for electrical equipment, which is crucial in medical facilities. The Wye connection allows for both three-phase and single-phase loads to be served from the same network, improving versatility and efficiency in distributing power.

Additionally, Wye configurations provide a neutral point that can help with the stability of voltage levels, making it safer and more reliable for sensitive medical equipment. In medical environments, where equipment must operate flawlessly to ensure patient safety, the balanced distribution and stability of the Wye system are highly valued. This alignment with safety standards and operational efficiency underscores its preference in the Air Force for medical facilities.

Other configurations, while useful in different contexts, may not provide the same level of safety and adaptability for critical medical applications, which is why Wye-powered systems are particularly endorsed in such environments.