What is the breakdown voltage of transformer oil?

The breakdown voltage of transformer oil is the maximum voltage that the oil can withstand without breaking down, meaning without forming an electrical arc between the electrodes. For new transformer oil, the typical breakdown voltage should be at least 30 kV (kilovolts) for a 2.5 mm gap between electrodes. A higher breakdown voltage indicates that the oil has strong insulating properties, which is crucial for the safe and efficient operation of transformers.