I have been using cheap fiber converters for this situation for years. If you have a surge issue of any kind, any difference in ground potential will go right through your equipment. The converters are about $100 new but you can get them for less than $10 each if you watch ebay. Converter Same with the fiber. 100m indoor patch cords with the connectors are $50 or more but if you watch you can get them cheap. I have the equipment to do my own terminations but it actually costs more, especially if you factor in my time. 100 meter patch cord You can use this orange indoor stuff if you carefully pull it through the conduit. I bought about a 50 rolls a few years ago for less than $10 each and we use is exposed on this wooden bridge that gets taken down every winter (and sometimes unexpectedly from flooding). Golf bridge in top photo We string it across just outside the railing with a few tie-wraps. Sometimes we can get two installations out of it but it's just as easy to throw it away. The only time it failed (besides flooding) was from a weedwacker. There are boxes on each end where the rest of the run is direct burial indoor/outdoor (also from ebay). It's used for a point of sale PC for the golfers to eat and drink. We have a second run for a spare that is a on a separate physical network that supplies WiFi out there "just because we can."