A method of installing a cable or conduit into at least one plastic pipe of a fluid carrying pipeline system, comprises attaching a first saddle fitting at a first location on said plastic pipe by electro-fusion, opening the pipe at the first location, introducing the cable or a pull body through the saddle fitting into the pipe towards a second location or retrieving at least part of the cable or a pull body introduced at a second location, and pulling the cable directly or by means of the pull body through the pipe. This allows installation of a cable without turning off the fluid supply.