A woman called in a case of trouble that “when the phone rings my dog cuts up a real fuss”. No one believed her but someone still had to go check it. When the repairman got to her house, he got a ring back and sure enough he could hear the dog in the back yard yelping yapping and carrying on.
He went to the back yard and opened the protector. The lady had a “party line” which rings to ground. The installer had been lazy and instead of placing a ground rod, or running a ground wire to the power ground, he had grounded the protector to a metal clothes line pole anchored in concrete.
She had metal clothes lines and the dog was chained to the line with a metal chain. Every time the phone rang the dog got zapped with 90 volts 20 cycles.
There is not enough current to injure him but I guess he really hated incoming calls.
Was told this first hand by the repairman.