Earthing of facility equipments

Commonly, either the neutral or earthing conductor/cable size are sentenced to as minimum 1/2 of phase conductor/cable size, bigger than 1/2 of phase size is better, maximum is the same as phase conductor/cable size. Otherwise you are directed to calculate by the help of A = (Ix√t)/K.

Where, A : Earth conductor size (mm2), I : Fault Current (A), t : duration of fault or trip time of CB (seconds), and K : material coefficient.

What voltage ratio of your transformer? Primary and secondary? what the specification of generator? Commonly for 20kV/0.4kV at MVside use earthing mesh type by 70mmsq of BC copper. At LV side also use 70mmsq but by single rod. But you have to calculate.

Yes, definitely. there is a standard for earthing design DIN VDE, IEC, and IEEE, you have to contact to those related standard organization.

Regards,

This is nothing like the capacity that you are talking of but in my home I ran a separate power and earth circuit for all my electronic equipment. The earth consisted of a 12mmØ cable with short tails going to each of the outlets. The improvement in the quality of TV reception was quite remarkable and may people commented on how clear the picture was.

What masu is describing is the NEC standard technique called an "isolated ground" receptacle circuit. Hospitals are generally the only other place you'll find them. Used to be thought of as good for computer circuits, but it has been found to be orders-of-magnitude better to install all electronic circuits on a panel with line-noise suppression, and make sure the neutral is full size and not shared between circuits. Not as good as an isolation transformer, but close and cheaper.

*If you have a studio situation, go with a parallel 60+/60- system for zer0 noise.

Just make sure it is also bonded to the same grounding electrode system per the other standard NEC requirements.

The U.S. National Electrical Code (NEC) has a detailed calculation procedure and specific requirements for this type of grounding, and it expalins it much better than any of us could do on here.

Conversely, most any electrical design shop or electrical contractor with an engineering department can specify this for you pretty cheaply.

If you need an online resource, and don't have the current NEC or the IEEE handbooks available, I'd HIGHLY suggest you click on over to mikeholt.com, where you'll find detailed, graphic illustrations of what to do, online courses, and I think even some free video discussions. They also have an active forum for more detailed electrical-only questions, particularly if you are in the US and it's a Code issue.

PR1ME computers used the system too. PR1ME also used shielded power cables and line isolation transformers. The transformers were feroresonant and had the secondary effect of giving you a separate earth neutral link close to the computers. I managed to get a transformer and the cables from a computer room that was being decommissioned so it cost me nothing.