Long ago I got a shock at work hooking up a network cable.

In those days we used shielded bi-ax. I had one hand on the end of the cable and grabbed another cable to connect to the next computer downstream.

Well, the first computer had hot and neutral switched, and the case was hot.. The second computer was wired correctly, and the case was at ground or neutral (not sure - could be both.) So the cable shield made a path from chassis to chassis.

If the first computer also had a ground connection, it should have tripped the breaker when we plugged it in. There was no separate ground wire on that three prong/hole outlet. The safety ground was theoretically supplied by metallic conduit, and there wasn't continuity all the way back. That shows one possible problem with not having a safety ground at the outlet.