[Beowulf] Emergency Power Off
Robert G. Brown
rgb at phy.duke.edu
Sun Mar 18 10:36:50 PDT 2007
On Sun, 18 Mar 2007, Jim Lux wrote:
> At 06:52 AM 3/18/2007, Robert G. Brown wrote:
>> To answer my own question (GIYF, after all:-) there is a white paper
>> HOWEVER, if you love your local firemen and want them to live (or love
>> yourselves and the other employees who sit near the data not-a-centers),
>> the same white paper says that an EPO switch is still a very good idea
>> for small server rooms and wiring closets that are not "data centers"
>> but are just "data closets" or "data rooms that aren't quite centers".
> Do not underestimate the power of lobby... e.g. The front matter of the IEEE
> Emerald Book, (which used to be called "grounding for sensitive electronic
> equipment") explains why the "sensitive" was removed. Mfrs didn't want their
> particular piece of equipment to be referred to as sensitive.
> There's a huge "small office and retail" sort of market for middling sized
> UPSes, and APC and the like would like to sell into that market as a "plug
> and play" product. Also, this is where the local AHJ can play a role. THEY
> can say, we don't care if your installation isn't in a room that meets ALL of
> the requirements of 645, we want you to provide a disconnecting means anyway.
I could wish that they made this a whole lot simpler. And perhaps
standardized so it would be cheap as well as easy.
> Another way that folks avoid the code is by putting the UPS into a rack with
> the equipment being powered. That puts it on the other side the "line of
> demarcation" between that which is subject to code and that which is
> "internal to the equipment" and subject to different rules. And, here, the
Hooo. Right. So the firefighters won't get electrocuted by big UPS's
IN a rack, only by smaller UPS's on the floor.
Makes perfect sense. Sure.
I'm going to try to figure out how to put an EPO in this room for less
than a fortune, even though I'm pretty sure that it isn't strictly
required. Even if it is just one that controls the UPS's -- so that
the building power can be cut externally and one can bop off the UPS's
on entering the room.
The building power is tricky enough as it is -- they have a gas
generator that kicks in transparently on loss of grid power (it's a
medical clinic). That is not my thing, though.
Robert G. Brown http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567 Fax: 919-660-2525 email:rgb at phy.duke.edu
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