Substation Battery Rack Grounding

Not working in a utility, I've never seen metal battery racks! Our traction substations (3kV DC electrified railways) use strong wooden racks for our 110V battery systems, and earth separation are regularly monitored. In our case, it is important to have very effective separation from earth, as there could be fairly large traction DC return currents flowing through earth under fault conditions. I can see that utilities could be different.

Outstanding answer, CJ. You nailed all the relevant points in clear language.

The IEE Regulation is very specific on this issue by saying ALL METAL SHEETS should be properly bonded to earth. Bonding of the battery rack is a very necessary safety measure to prevent electrocution. So do the bonding, a regulatory body have asked U to do so and it has been proved right by all of us in Electrical Section of CR4.

Secondly, if the negative terminal of the battery is bonded to the rack, the rack should be separately earthed and not through the sub station ground grid. Ur fear of ONE, will occur if done other wise.

Dickson.

Very nice explanation. Have you any experiences from Nuclear power plant about grounding battery racks? One guy are still saying that it is not necessary because racks are itself connected to the anchor plate, beucase we have thick layer of epoxy paint...is this sentences relevant for removing grounding from battery racks? ANd floor must be coated with anti-acid paint only or anti-static / insulated mat??? In Nuclear power plant you have IT system. thanks.

Dear GUEST,

In response, I have no special personal experience related to nuclear power plants.

You can generally rely on the accepted published standards, such as OSHA 1926.403-1986, but when it comes to something as sensitive as the implications of NUCLEAR power, the control, communication, IT and emergency systems and their power sources you can expected greatly increased caution, duplication, redundancy, anality and banality to the Nth degree.

This forum, at least my part in it, does not rise to that degree nor would I attempt it.

I can read however, and just completed several minutes of in depth review of several detailed reports, records, Standards etc on this subject. It's simply amazing what power lies in GOOGLE and de-classified documents.

Even with that availability, I would strongly recommend that you contact a few of the engineering companies engaged in the sales and engineering specifically geared toward NUCLEAR POWER installations. They were quite easy to find on the internet. I'm certain that what you have asked of us is not a state secret, and since it is safety related, I'm convinced they would gladly share some prepared materials they have available for public distribution on the subject of your question.

Regards, CJM