I have been asked to design a 250Kw solar system with ground mounted frame work and would like to put this out to the forum for feed back.

The DNO TN-S 400A supply point sw room is 200m away from the proposed solar inverter location which is within a GRP walk in enclosure. The ground mount PV system is going to be a further 50m away from the inverter location and there is no public access to this location only skilled maintenance staff.

My idea is to run a sub main to the inverter sw room and create an isolated TT earthing arrangement at this point, not exporting the earth from the main building. At the inverter room location install an earth rod for the remote isolated TT system and equipotentially bond all sw gear and solar frame ground mount metal work at this point all protected by earth leakage devices , one per inverter, and the main sub mains will also be protected at source by earth leakage device.

Please can I have some thoughts on this methodology thanks.