I need to add about 50ft to a cat5e run that's about 300 feet by the time it will terminate. It's a pretty low volume of data that it needs to transmit so I guess I'm not super worried. I know its not a good idea but I wasnt involved in the planning, just need to make it work as well as I can. My thought is to use a punch down splice box enclosed in a weatherproof box since its outside. I could also put the rj45s on the ends of the cables and use a coupling like that but I really dont know what would be more reliable. I appreciate any input. It will also be following all code requirements for protection by using rigid pipe to protect the cable as it comes out of the ground to the box then emt to the inside of the building and at least a nema 4x box maybe higher rated since it's in a bit of a vulerable spot for water and dust.