I am an avid reader of your website for a long time. I often wonder how many lives your site saves each year, not only ordinary folk's lives, but professional installers as well.

The attachment is on the MINE SAFETY AND HEALTH ADMINISTRATION website, which you may view live at http://www.msha.gov/FATALS/2001/FTL01c02.HTM

It REALLY supports your main point about touch potential, ground rods, and providing a solid path to the source to open the circuit’s overcurrent protection device! The essence of the case is human contact to a control power neutral which had become energized with primary power. The control circuit neutral was hard-connected to a ground rod, but not bonded to the secondary system.

As you point out so often, had this been done, the plug described in the incident, which killed the installing electrician, would never get to the arcing and smoking point. Had the grounded wye of the capacitor bank been tied to the primary neutral as well as the rod, the primary fuses would have opened and aborted the fault current down the capacitor bank grounding conductor.

I suspect situations like this are more common than we think. How sad that this mine was provided with a solidly grounded wye neutral for 'free', and they didn't even bother to bring it in and use it for safety.

Bob Nelson


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