Many thanks for the comment , silica gel might be a help.. Part of my problem is that this is a university , the cabinets exist and have been paid for by a different project , we are being asked to use what we have , I could put a cheap converter Fibre- CAt 5 POE the issue , would be that those units are not manageable ... and then support etc .... We basically need to do a test over christmas and see how it pans out ..there is already a DC supply in the cabinet , maybe I could look at using that ... thanks again Rod