It's normal for a device to describe its insulation according to standards, for example UL1577 and DIN EN 60747-5-5 in this case. Often they describe max voltage for short times, like 60s or 1s. Sometimes they describe the "working voltage," which refers to continuous operation. Depending on your device and your country, you may be required to use parts certified to specific standards.
I have never seen any PVI with a working voltage >1kV (at least not in a monolithic package like this). Not even sure if any certifications extend to such voltages.