Power For Server Room

[AJ]

Hello All

I have a server room which will be running eight - nine servers. Currently only three, plus a router, and a UPS are powered by what looks like to me an extension to the ring main (Not sure??) The supply to the cab is via a 13AMP socket

Basically there is a cable which has been spurred from a socket in the end room of the house which runs into the garage and supplies the lights and sockets for the garage and server room next to it. There is at least one Fused Connection Unit in the mix from memory.

In addition to the final eight - nine servers I have an aircon unit that will be installed, plus there will be various office kit that will need powering. Taking the load into consideration, even though there is very little on the upstairs ring main where the supply comes from I am proposing to get the server room powered on its own circuit in some way.

I was thinking a radial circuit from the existing CU would maybe be the best approach. However looking at the CU there is only one unused socket or whatever the correct word is. Would it be better to install a new CU in the server room itself or just use this spare socket and run a radial.

Also would it be expensive to get a seperate supply completely run into the server room. Its for a business and therefore I really need to seperate it from my domestic supply.

I will be getting a proper spark in to do this, but I'm just curious to hear what the best solution would be so I dont get ripped off!!!!

Also any guestimates on cost?

Cheers

Richard

[Andy Hall]

You haven't given an indication of the power consumption of the servers or the other equipment.

Without that, it's not possible to say.

[Dave Liquorice]

Seperate as in a new supply/meter a supplier or just a sub-main privately metered after your existing supply meter?

Personally I'd take a suitably sized sub-main to the server room and then distribute that as required. Bearing in mind that the Aircon will take a fair bit and be a "nasty" load.

Running a business from home, hope you have looked at change of use and/or planning permissions etc, particulary with space dedicated to business use.

[Andrew Mawson]

There is

though

circuit

curious

off!!!!

servers

But I would say that you should have a 'clean feed' direct from the CU to avoid electrical clicks and bangs from any other equipment. I even do that at home for my 24/7 pc

AWEM

[Clive George]

For a PC at home, wouldn't a UPS do that and more without the need for any tedious rewiring?

cheers, clive

[The Natural Philosopher]

The deluxe solution would be a seperate supply completely wit its own meter and CU.

Failing that second best would be to run something bloody thick with something like a 60A capability off your existing CU slot, and put a sub CU in place in the room, and build rings for the computers and a different circuit for the lights as well.

You need all that sort of thing if you are going to use UPS type stuff anyway, and if you have any sense you will litter the place with 13A sockets on several different ciruits ...

The lest attractive option would be to use the spare CU slot to simply run a new ring on.

But I would prefer from a maintenance POV to have a sub distribution box with switchable circuits on it and a main switch to flip that totally isolates the room in cases of emergency.

[Andy Hall]

True. So do I.

However, in the absence of information, we don't know whether we are talking about a few little PCs or some heavy grade iron requiring three phase supplies, substantive airconditioning and ear defenders to walk into the room.

[Colin Chaplin]

And with it, it usually impossible to say too ! I'm assuming you're talking common-or-garden HP/ Dell 1U/2U type stuff?

Their power consumption figures they publish are somewhat inflated.. when looking to site about 200 servers, realsing we'd probably need our own coal fired station to power them ;-).

Even with lots of disks and all the machines being turned on at once, I'm not sure where they get their figures from.

An example of my point (not to copy!) I saw 20+ servers in two racks that had been setup for a few weeks, then a power failure. Cause was traced back to EVERYTHING going back to a standard 13AMP plug where the fuse had finally given up.

I'd be tempted to have the aircon on a different ring, and also make sure it's not above the servers....

Colin

[Lurch]

On Fri, 16 Mar 2007 15:48:32 -0000, "Colin Chaplin" mused:

I would very much doubt the air con will be on a ring at all if it's any good.

[dennis]

No need. A UPS will take care of the noise with ease.

It sounds like the OP wants a meter and feed and CU just for the server room. If he wants a separate supply from the supplier its going to be expensive.

Why he doesn't just lease some servers in a server farm is a more interesting question.

[tony sayer]

In article , dennis@home writes

Why doesn't he just buy an electricity meter and feed his "business" part of the premises from the domestic incoming supply via his business meter and then charge a cost per unit. Like I do?..

That way its one less bill, one less set of standing charges etc...

[Phil B]

Yes - and a few extra pointers - all learned the very hard way from rooms with scoresof servers.

I see you are talking of 8 or 9 servers, but I expect that by the time you include monitors, comms kit, extra disks, printers, phones etc you will be up to 30 power points. Adopt a wiring technology which allows easy expansion to 40, 50, ...if you think it will grow.

If you use UPS then choose it very carefully. Most computers have a very odd load characteristic - as the AC voltage rises from the zero point they consume little or no current, then at a critical voltage they really suck current. The voltage is sinusoidal, the current has 100 'blips/sec'. We've measured peak currents from a big UPS seven times the RMS peak which you'll get from a resistive load, and this will kill a badly specified UPS. The UPS needs a very high peak volt-amp rating. Make sure you can revert to raw mains easily if it fails. If some of your kit has dual supplies, could you feed one from UPS, the other from raw mains?

You might also like to consider whether you want to be able to ditch some services in one fell swoop either by software or with one or more switches in case of a power cut. Not only will you have limited life in your UPS but you are also limited on dissipation into the room as you will have no cooling. You will then be able to just keep 'essential' services going for a maximum time.

Are you going to do any repairs with open live cabinets? Circuits to protect staff?

Want special provision for stuff other than computers eg vacuum cleaners on a separate supply? We were once horrified to learn that we had a drinks machine wired into our UPS!!

If your operation gets really big, then you will be into 3 phase stuff. Not a legal requirement but not bad practice to segregate the 3 phases to separate areas in the room so nobody can touch across two. Load balancing also becomes a real headache.

Try to keep people out of the room - don't have it as a regular working environment. Computer environments are terrible to work in (dry, hot), people dissipate heat and (ssh!) drop dirt!.

Oh, and do put a sticky label on every 13A plug and maybe every cable saying what it is!

Room security? Non water fire extinguishers ? The list is unfortunately almost endless.

Hope this helps. Phil