Questions on different practices?

[tramp67]

A thumper van? Wow, that brings an image to mind! Picture a brown chevy van, with the tinted bubble windows on the sides, the interior wall to wall, floor to ceiling brown and gold shag carpeting, a striped mattress on the floor, covered with stains from who knows what.... Sorry, LA, I just couldn't pass that one up!!!

But really, always new things to learn. A thumper van sounds like a WWII vintage piece of equipment, I think I saw a picture of one in about the 3rd or 4th edition of the Lineman's and Cableman's Handbook. Do you really have any equipment nowadays to test underground primary cable that requires it's own van? It would be interesting to see, as it's something I've never run across yet.

As far as thumping through transformers, the few thumper manuals that I've actually read cover to cover state that it is perfectly safe to thump through transformers, and it is basically a waste of time to disconnect each transformer, stand off the primary, move the thumper, .......

Back to the AC or DC question - I guess maybe that's where the thumper van comes into play? I never tested or thumped cable using AC, and really don't understand how it would work well or the reasoning behind it, not to mention the tremendous stress it must impose on a cable. After all, underground primary cable is basically a long capacitor, and to subject it to an alternating current under fault conditions is proven by the cable manufacturers and EPRI to be very damaging to the cable, much more so than the DC current. Maybe that's where the exploding thumper vans come into play? I don't know everything, never claim to, but this one just seems too far out for someone to be doing, with all the technology out there today.