I agree with @PhilipDAth, the X model that supports mGig is designed for PoE so I'd be pretty sure that it would reject the non-PoE power supplies.  I know it does seem daft, but you have an unusual use case.  Although we have just bought 4x 355s for a datacenter with a total PSU capacity of >8KW and there will be one VoIP handset as the total PoE load...  ... View more