Having turtle tanks through the years I've been shocked by broken heaters tons. Then I changed to sump and I broke two heaters myself and got shocked both times. I got shocked by my 500 watt heater that I keep for quick heat ups, like preparing saltwater, last weekend in a bucket because I had one hand in the water and the other holding a pump outta water (still running plugged into same strip) and somehow I completed the circuit. Can't see any signs of breakage on heater.
I use a yellow shock breaker plug on big tank. Nothing on picos and pond is on gfi.
Even with straight plugs to outlets I've never had anything too scary. The shocks themselves range from arm feeling suddenly numb and hair pours stinging to prickly pours and tingles before I realize I'm being shocked. Lately I've been shocked at least twice monthly while setting up new sump setup.
I was just told by my mother that she watched 20/20 where woman got electrocuted by aquarium and died and came back.
What Brian said... lol only to add I've run into stray current issues that effected the lateral line in certain species of fish. One of the first things I always rule out when dealing with HLLE cases. imo w/ so much electricity around our tanks its best to ere on the side of caution and "aim" for no electrical current in our tanks as its inevitable to happen. Not to mention faulty equipment is just dangerous to Ourselves and anyone/thing around/in the tank.
Everything we have goes into a rated power strip never directly into the wall.