Thanks for all the responses, sorry it has taken so long to reply. I suppose you would have to be really unlucky to come between 2 seperate upss so it might not be as bad. The fire brigade are aware of what the room is for anyway. If there is no water you would actually have to go and grab at them to get contact with anything live.

We have 160Kilos of HFC227ea extinguishant and then we also have some very large hand held CO2 extinguishers as well as some dry powders in case there is a battery fire.

we keep entry controlled with digital locks and trained staff. There is also a status panel to check and the system is put into manual when the lights are turned on.

Do we need to put those stickers that warn of 400V between <-- --> on the sockets that are close and on different phases?

Thanks!

I took my time, I hurried up, The choice was mine, I didn't think enough