Yes – a 60 Hz breakdown voltage test is generally acceptable as long as it’s performed to the correct standard and you report it that way. The common BDV standards treat «power frequency» as a band, not a single number: ASTM D877 specifies an AC test in the 45-65 Hz range, so 60 Hz is within spec. IEC 60156 is also a power-frequency method (typical sources are around 50/60 Hz). What matters more than 50 vs 60 is that you keep everything else consistent (electrode type/gap, voltage rise rate, oil temperature, conditioning, and cleanliness). If you’re trending results, don’t mix methods (e.g., D1816 vs D877 vs IEC 60156) without clearly separating them.