How many secondary bushings does a 277/480 volt can have?

A 277/480 volt transformer typically has two secondary bushings. This voltage configuration is commonly used in three-phase systems, where 480 volts is the line-to-line voltage and 277 volts is the line-to-neutral voltage. In a three-phase transformer setup, two of the bushings provide the necessary connections for the three phase lines, while the second bushing serves as the neutral connection.

This design allows for both the 480 volt three-phase service and the 277 volt single-phase service, commonly used for lighting and other applications. The presence of only two bushings is significant because it ensures that the transformer can effectively distribute power in both voltages without redundancy that additional bushings would introduce. Thus, the configuration is optimized for the most common uses without unnecessary complexity.