It should be obvious, but nevertheless it is worth emphasizing that hi-pot testing is always performed with the equipment powered off. But that’s just to avoid damaging it from a functional viewpoint. After all, we can’t safely apply a steady 2500-V on the output or across any power supply while it is working!
Some engineers question whether it makes any sense to consult the clearance and creepage tables of the safety standard for deciding how good the separations need to be to pass the hi-pot test. They argue that the hi-pot test is conducted with the device powered off, whereas the clearance/creepage tables in the safety standard assume that the equipment is actually powered up.
To answer that, however, the purpose of ...