we need to get a cable from one end of a boating marina to the other, buried is not possible and there are no walls to fix to, So the choice left would be to go overhead, Confusion reigns, reg no 709.521.1.5 says cables in free air suspended from or incorporateing a suport wire shall not be used...now go to 709.521.1.8 and they start talking about overhead cables, somebody give my brain a rest