For a 347/600-volt, 3-phase service, what must the secondary voltage rating of the transformers be?

In a 347/600-volt, 3-phase service, the secondary voltage rating of the transformers is crucial for ensuring compatibility with the electrical system's design and requirements. The 347 volts represents the phase-to-neutral voltage, while the 600 volts indicates the phase-to-phase voltage in a wye configuration.

When transformers are wye banked, each phase is connected to a common neutral point, which allows for the use of the phase-to-neutral voltage (347 volts) in lighting and low-voltage applications. This setup is commonly used in commercial buildings and for supplying lighting loads.

Choosing 347 volts as the secondary voltage in a wye configuration ensures that there is an appropriate balance in the system and allows for effective power distribution. Additionally, using a wye connection enables the system to facilitate different voltages as needed based on the load requirements while maintaining safety and operational efficiency.

The other options do not meet the necessary specifications for this service configuration. For instance, a delta banked system at 347 volts would not provide the needed phase-to-neutral voltage accessible to typical applications in a 347/600 volt service, and a 480-volt rating does not align with the specified system voltage. Therefore, selecting 347 volts with a