Hi,
I have applied all kinds of materials (UE4 Default/Custom) to the cable having no effect. Here is an image of my scene with the details pane. In this instance I have applied the default M_Basic_Floor material http://i.imgur.com/b5fiaYP.png
The cable is on the right, which is attached to the Telephone pole on the left.
As I have said before it is only happening in this particular project. I can get it to work again in a clean project.