These cables are run with all phases in a group. I think just maybe I have the problem under control. As of last evening when I checked these pumps, everything was still running good. I think that by thumping, I was just destroying this cable and causing myself undue headaches. I will not thump them anymore.
Thanks to everybody for all the input. You gentlemen are great. The knowledge of this site is unbelievable.
thanks again, Merlin
