Application Notes Relating to Standard voltage configurations
Normal Voltage Configurations: Three-phase power is required for almost all industrial and high power commercial equipment. There are many economic benefits that make three phase power attractive for this type of equipment. Transformers, filters, power supplies, and conductors can all be smaller and less costly with a three phase system than with a single phase system of equivalent power. In the United States, there are two main types, or topologies, of three phase power. These are called Delta connected power, and Wye connected power. There are some similarities between Delta connected power and Wye connected power, and many differences. It is important to understand these two varieties of three phase power in order to properly specify power for your critical loads. Single phase power as used in residential housing and is also listed below.

120/208 3-Phase Wye 208 volts between all 3 phases. 120 volts all 3 phases to Neutral

120/240 3-Phase Delta with High Leg 240 volts between all 3 phases. 120 volts to ground(Neutral) for phases A and C. 208 volts to ground(Neutral) for phase B (High Leg). Label B phase Orange.

120/240 Single Phase 240 volts between both phase conductors. 120 volts both phase conductors to ground(Neutral)