The center-tapped configuration of the secondary side of the Distribution Transformer provides following voltages to the Service Entrance Panel:
• 120 VAC between the Hot Leg L1 (Phase A, Red wire) and the grounded, center tapped Neutral (White wire). The oscilloscope trace of the
voltage waveform between the Hot Leg L1 and Neutral shows the voltage rising in the Positive direction at the start of the waveform
• 120 VAC between the Hot Leg L2 (Phase B, Black wire) and the grounded, center tapped Neutral (White wire). Please note that the
corresponding oscilloscope trace of the voltage waveform between the Hot Leg L2 and Neutral shows the voltage rising in the Negative
direction at the start of the waveform. This indicates that the two 120 VAC voltages are 180 degrees out of phase
• 240 VAC between the Hot Leg L1 (Phase A, Red wire) and the Hot Leg L2 (Phase B, Black wire)