A transformer with a nameplate rating of 240/480-V primary can deliver nameplate-rated voltage to a load when connected to what type of breaker?

A transformer with a nameplate rating of 240/480-V primary means that it can operate at either 240 volts for a single-phase system or 480 volts for a three-phase system. When connecting this transformer to a load, especially for the 480-volt setting, a 2-pole breaker is appropriate for several reasons.

Using a 2-pole breaker allows for the connection of two phases of a three-phase system, which is necessary to achieve the 480 voltage. The 2-pole breaker connects these two phases together, enabling the transformer to deliver the required voltage to the load effectively. This setup is typically used in systems where the transformer is providing power to a three-phase load that operates at a higher voltage level.

In contrast, a 3-pole breaker would be used in situations where all three phases of a three-phase system need to be protected or utilized. A single-pole breaker is only suitable for connecting to a single phase at a lower voltage (such as 120 or 240 volts) and would not be capable of delivering the higher 480 volts effectively. A 4-pole breaker offers an additional feature by allowing for a neutral conductor, which is not necessary for this application focused on delivering the