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Another way that works well: the cal lab room is supplied with a full isolation transformer and it's own safety circuit breaker distribution box coming off the transformer secondary: In that situation (a.k.a. an Island AC System) it was able to have it's very own ground rod array right smack dab in the middle of the lab room floor. Because it was an AC power system completely galvanically isolated from the utility grid, it was able to have a completely -local and isolated- grounding system - and it was setup to run on its own battery / inverter supply also. 24VAC and 48VDC supplied to test benches directly which is nice for lab use, and to keep things extra extra quiet the overhead lighting switches to 12 and 24VDC halogen incandescent. Nice. You could run LED lighting also as long as no switching power supply used, but halogens provide the best CRI.
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Hi Mr Diodes
It looks "island ac system" is the best while it is not so easy for us to achieve.
I looked into some national codes, the ac system from utility co. is TN-S, TN-C, TN-S-C, TT...each one has different grounding point..so I'd think better to connect breaker panel ground and utility ground to lab ground then to the EARTH, if lab ground is really the EARTH..