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On 11/21/2019 at 11:05 PM, mtwitty said:

Equipment grounding conductors in intentionally ungrounded systems are designed to actuate an alarm (ground detect devices). They do not cause overcurrent devices to open as they do in grounded systems. The purpose is to allow continuation of operation when one phase develops a ground fault. The grounded leg (fault) is at ground potential, so is not necessarily a shock hazard to personnel. The alarm should be addressed and the fault found and repaired ASAP. If a second phase develops a ground fault, this causes a line to line short and shuts down via the OCPD. Ground faults are common in industrial facilities and this ungrounded system is used to allow uninterrupted production until the fault is found. It's not the safest system, but is common. The "corner grounded" system like in the photo I posted intentionally grounds one phase leg and will open the OCPD if either of the other 2 ungrounded phase legs have a ground fault. (line to line short) An ungrounded system basically becomes a corner grounded system if one leg develops a ground fault. As far as single phase systems that are not grounded....that would be a faulted system and not by design. I know this is way over the top for residential and home inspection discussion but it is good to have a basic understanding of IMO. If you look at the photo I posted, at a glance, it looks like a single phase sub panel that we see everyday. Only giveaway is all 2 pole breakers and some blue wires. Although very uncommon, this could be present in an inspection of a commercial property. Hope this makes some sense and answers your question. I apologize for side-tracking this thread. Didn't mean to get so deep in this. 

Thanks very much Mike.  This is interesting.

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