Currently I am designing a circuit that is required to be PoE powered. We are debating whether to use an isolated or a non-isolated supply.
The device is wall mounted and in a plastic enclosure. No metal parts are exposed to the end user.
This answer said that this is the only requirement to be able to use a non-isolated DC-DC converter, but I would like to know if someone can reference an actual document were this is stated. It will be sold in Germany, so there may be additional regulations that do not apply to the whole world.
EDIT: To be clear: we are designing a powered device not a PSE.