Author -
Submitted By -Thumper Notes
For the guy with the thumper problem--- Capacitive discharge devices like most thumpers (we use Hipotronics, others are similar) will build a field on the truck they are mounted in. YOU must ground the truck chassis and bond the thumper into the grounding scheme to drain the charge that develops. Your guy had the charge go through him - to the "grounded" tree he touched. The hot boots just re-directed the current so it went to the tree. If he was in normal shoes he would have been poked too, the circuit would have been through his feet to earth.
We had a few thumpers mounted in pickups with side door toppers. After a few "shocks" we found out it was better to make a rule that said the operator had to be inside the truck to limit exposure to ground. We also made a rule that said the thumper vehicle had to be chassis grounded and barricaded. Now we only seem to have problems when somebody "cheats" those rules.
As a side note we had a guy out listening for the thump once who got on his hands and knees to hear better. The ground was wet and he took a pretty good shot while he was kneeling. Most of these thumpers will put out upwards of 50,000 DC and they can hurt you pretty bad if they are not used right.