Last week, one of the panels I built blew up during a thunderstorm. Thankfully, it was in an unmanned building, but it still cost my employer about $20,000. This was an inexcusable oversight on a trivial technical problem. Hopefully you can learn from it!
Grounding is a safety system, of sorts. The goal is to remove people (and, to a lesser extent, equipment), from electric shocks. Some excellent resources for industry are in The Electricity Forum and RealPars! (If you were looking to find out about the same topic but in your home, check out The Spruce or Waypoint Inspection.)
This was a single-phase panel in a remote building. It was hardwired to several small (5-25 HP, 480V3P0) motors and sensors, all of which were outside. I was using an Emerson Islatrol IE-120 (now the ASCO 277) to filter power. It was powered from the same bus as the motors. I made the mistake of landing the ground, hot and neutral directly on the device, then pulling the ground wire coming out of it to the ground bus of the cabinet. It looks like I should have landed the ground from the wires feeding the cabinet on the bus, then ran a wire from the ground bus in the cabinet to the power feed into the Islatrol.
I am not sure how our grounding will look in the long run. Industry systems end up with lots of ground loops and I hope the guys audit it well enough to find the issue.
Check your grounding on installations! If unsure, ask a friend to look it over. This was a needless and expensive mistake.
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