I wanted to pass this along. Last night, I was at a web site frequented by heavy duty computer geeks (slashdot.com) A member asked a question about adding a 240 outlet for a new server. There were a couple of hundred responses and the tone of everyone I looked at was, "Don't try and kill yourself and screw up the whole server room. Go hire a competent electrician and get it done right." It's nice to know that there are people out there who realize when to call in a pro.

Good advice, but what sort of size server is it that needs 240V?

Paul I am not sure that there are 240 volt servers, but I do know that there are 208 volt servers, hubs, switches, all the same stuff that normally is 120 volt.

At least I hope they where rated 208 because that is what the plans show for feeds.

A pretty common outlet I install in data centers is a NEMA L6-30R (Locking 250 Volt 30 amp rated) single phase grounding receptacle.




[This message has been edited by iwire (edited 08-20-2003).]

Most computer power supplies have a 110/220 switch. Some auto-sense.

After reading my post I should make it clear that the 30 amp outlet does not directly feed servers.

Typically the L6--30R feeds a UPS like this , from there the power will go to a small Power Distribution Unit out of the PDU with IEC 320 C13 power cords to the hubs, servers etc. all at 208 volt.

Is it possible that using 208 volt instead of 120 volt helps to lessen the problems with non-linear loads?

This was a Sun box. Upper mini, lower mainframe class box. These are not what you see on a desktop. These thing have multiple redundant power supplies, many gigabytes of memory, and large drive arrays. Such a system might take up a couple of 8' 19" racks. We have a relative small server set in the next room and its running off 2 5000 watt UPSes. Power planning is a big issue for data centers. The current those transistors draw is really small but millions and millions of them start to add up. Out of curiosity, I just went over and looked at the panel for our Process Control Room. 500 amp., 120/208.

Ah, OK, it's a big server drawing a fair amount of power.

I know that some of the earlier mini systems (PDP-11 etc.) were run on 208V years ago. Incredible to compare the computer power in one of those with the server you're talking about.