This talk will present a method of testing package safety isolation. Testing was done on samples of power devices with an integrated high voltage switch with internal primary-secondary isolation, used in automotive applications. Pre-fault HiPot testing at the rated voltage (4500V) for a duration of 60 seconds was done on sample ICs. Then, a fault condition, which caused localized package damage near the high voltage switch, was induced. The damaged parts were subject to post-fault HiPot testing – identical to pre-fault testing. The main objective was to investigate the preservation of integrity and strength of the isolation barrier even after a fault condition caused damage to the package.