We did TDR with a garden variety O scope. (tek 453 works, 475 is better) You just feed a sharp edge like "B out" onto the transmission line with a T BNC connector on the scope lead and watch the reflected signal. If you know the speed of your transmission line you can compute the location of the anomally but I like to create a fault at a known spot to check my guess. I suppose it works on anything but we used it on signal cables. When you see what will make a "bump" on the signal I can't imagine what a chunk of Romex or wire in pipe would look like. I bet you could see every staple and kink in the conductors. J boxes would certainly be a mess.
