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In a 3-phase, 4-wire, 120/240 volt delta-connected service, the arrangement allows for three phases (labeled as A, B, and C) and a neutral wire. The voltages in this system are generally configured to provide both a higher voltage and a lower voltage option for various applications.

The high leg, also known as the "wild leg," is typically associated with one of the phases in a delta connection that has a higher voltage relative to the ground than the other phases. In the case of a standard 120/240 volt system, the phase with the high leg (commonly associated with phase B) provides a voltage of 240 volts from phase-to-phase and 120 volts from phase to neutral (or ground).

Since the neutral is connected to the ground, the high leg's voltage to ground is identified as 120 volts. This is because the 240 volts represent the voltage between two phases (for instance, between the high leg and one of the other phases) and, when measuring from the high leg to ground, the voltage drops to the lower level provided by the neutral connection.

In summary, the high leg in a 3-phase, 4-wire delta system yields a voltage to ground