The distance between electrodes in a Breakdown Voltage (BDV) test kit depends on the testing standard being followed. The most common configurations are:
ASTM D877 (U.S. Standard):
Electrodes are flat, circular disks.
Gap distance: 0.1 inch (2.54 mm).
IEC 60156 (International Standard):
Electrodes are typically spherical (12.5–13 mm diameter).
Gap distance: 2.5 mm.
Key Notes:
The slight difference (2.5 mm vs. 2.54 mm) reflects regional standardization preferences.
Always confirm the gap with the kit manufacturer or the applicable testing standard (e.g., ASTM, IEC, or others like IS 6792).
Proper electrode alignment and cleanliness are critical for accurate results.
For transformer oil testing, 2.5 mm (IEC) is widely adopted globally, while 2.54 mm (ASTM) is common in the U.S. Always refer to your lab's protocol.
