Ok, not strictly D-I-Y i know, but I have been asked to come up with some specs so that we can get quotes for a new power supply for our server room at work.
W have 3 tall racks (30U from memory) round about 6 - 7 feet anyway which are mostly stuffed full of Dell servers. These are rated at 2 Amp (The 1U jobbies) and 5A (2U jobbies). I don't know if this is the maximum they draw at start up, or if they may take more at startup. What I do know is that the 30A breaker which feeds the radial circuit they all go back to (via a few UPSs) trips out if the power comes back on after an outage
This can be a bit embaressing if we are all asleep in our beds and there is a power cut. The sequence goes something like
Power goes off,
UPSs continue to power equipment
Backup generator kicks in
MCB opens
UPSs keep the servers up for 10 or 15 mins
Then everything goes down.
If we are here when it happens, we just put the breaker back in while the UPSs are holding up and live to fight another day.
Anyway, to the question (I hope I haven't asked this before, I couldn't find it via google) Is there a rule of thumb for specing power supplies for these racks? Based on the rating plates, I could allow 2.5A per U, but I don't know if I need to allow extra over what it says on the rating plates of the servers, or if Dell have already done that. Does 60A per rack sound about right, way over the top? Way under?
Assuming it is right, what would be the best way to provide it? A number of 16A or 30A Industrial sockets?
Answers on a postcard please. :+))