I was working on installing some play area lighting at a Mcdonalds a long time ago and another electrician showed up to trace some underground wiring to a monument sign that had lost power. He had an oscilloscope, the kind that looks like a small TV. He said he was able to determine the length of the wire between his connection and the nearest splice by the waveform on the screen. I was impressed! Didn't stick around long enough to see whether he found the bad connection or not.
Thanks for the replies!
