What condition must be checked regarding tap settings before paralleling transformers?

When paralleling transformers, it is crucial that the tap settings are equal. This ensures that both transformers operate at the same voltage level, which prevents circulating currents that can occur if there is a difference in the voltage output. If the tap settings are unequal, one transformer might take on a larger share of the load, leading to potential overheating and reduced efficiency.

Setting the taps to equal values allows the transformers to share the load evenly, optimizing performance and enhancing the system's overall reliability. In this context, maintaining identical tap settings is essential for achieving stability and avoiding damage to the equipment.

The other answers suggest various acceptable tolerances for tap settings, such as allowing them to vary by a specific percentage or stating they should be at maximum values. However, these conditions do not align with the best practices required for safely paralleling transformers. Maintaining equal tap settings is the standard to ensure safe and efficient operation.