Have you ever been frustrated trying to find the actual cause of a high voltage failure in a cable assembly?   The type of high voltage failure can give clues to the type of defect occurring.   Pinched and narrowed insulation causes dielectric failures while contamination and humidity are most likely to cause insulation resistance failures.   To better understand these types of failures and to more easily identify their root causes see our second video on High Voltage testing.

Learn more about hipot errors.

To lovers, "Passion's Law" may be interpreted as "opposites attract."   But Paschen's Law explains the breakdown in air for high voltage.   Why do high voltage test specs usually start around 500 Volts?   In air, at least, there is a minimum voltage to create an arc or dielectric failure.   Strange as it may seem no matter how small the gap, two conductors will appear to be insulated until at least 327 volts is applied between them.   There are good explanations and technical details on this law at:

As the voltage rises above 327 volts, temperature and pressure will influence the air gap at which a particular voltage will cause a breakdown.   This is one reason why aircraft wiring and avionics used at high altitudes requires more rigorous design and testing.   As voltages get higher, the shape of the conductor surface has a significant effect too.

If you get dielectric breakdown at one voltage but an assembly passes at a lower voltage, use our High Voltage Arc Gap Calculator to characterize the distance between conductors in the defective assembly.   You can also play with different voltages to estimate the voltage required to detect a particular defect that you have identified in your assembly.   For more answers to questions on high voltage tests be sure to review our frequently asked questions page at:

See us next at these shows:

• Assembly Technology Expo Chicago, IL      Sep 27-29
• Aerospace Testing Expo Long Beach, CA      Nov 8-10