What is the reason for looking for a reading of zero when phasing lines?

Looking for a reading of zero when phasing lines is essential because it indicates that the phases are at the same potential, meaning there is no voltage difference between them. This is crucial when connecting or linking different phases, as a zero potential difference ensures that equipment will function properly without causing faults or overloads.

This practice helps in maintaining system stability and protecting both the equipment and workers from possible hazards. When phases have equal potential, there is a reduced risk of short circuits and equipment damage, which can occur if phases are improperly aligned.

The other options, while they may relate to electrical safety and system integrity, do not directly address the significance of a zero reading in the context of verifying phase potential differences. For instance, while safety is indeed paramount, the zero reading specifically serves to confirm that the phases are aligned correctly without voltage disparity.