I stand (or sit rather) corrected. My experience comes from the offshore where eventually, everything ends back to the vessel hull. The current plant I'm at in Northern Alberta shows details for the "isolated" ground system, and there is indeed another tail from the grounding delta back to the...
The "Isolated" ground sytem referred to by me is on the controls/instrumentation side where all of the individual sheild drain wires ultimately end up to ground. There is no interconnection between this ground and the equipment "safety" ground.
The control equipment itself is grounded to the...
I've never thought to question the "why" of it before, but 99% of industrial specs I've worked with for purchasing require 200% neutral in all panels.
Now it makes more sense. Thanks for the insight!
I have seen where the equipment within the containerized building is grounded to an isolated bar within the container and then, when installed at site, the ground bar and the structure itself are both connected to the main system ground. The only time I've seen an independent grounding system...
I don't have a documented reference for this other than what I was told by a switchgear tech. The enclosed bus in a metal clad switchgear, uninsulated, requires about 1" per kV to ground. So on a Wye connected 4.16kV (5kV) system, you would require 2.4" of clearance from the bus to ground...
