Distribution transformers can be configured as which of the following options?

• A. Single-phase or three-phase
• B. Single-phase only
• C. Three-phase only
• D. Neither

Answer: (C)

Distribution transformers are built to serve different kinds of loads, so you’ll find both single-phase and three-phase configurations in practice. A single-phase transformer steps down voltage for a single-phase feeder to supply residential or light commercial loads. For larger three-phase services, you can use a true three-phase transformer or a bank of three single-phase units tied together to form a 3-phase bank. The configuration chosen depends on the service voltage, load balance, and how the network is laid out (including whether a delta or wye connection is used). So distribution transformers can be configured as either single-phase or three-phase to fit the system needs.