Q: Building a small machine room?

Andrew Latham lathama at yahoo.com
Thu Sep 18 11:14:20 EDT 2003

Keep in mind that the below mentioned Disconnects are required by the National
Electric Code. The NEC has an ever growing section on computers (low voltage
telecommunication devices & rooms)

I friend who taught me the NEC is also a writer for it. He being an old
electrician himself stated that the code is for saving lives and should be 
read as such. Yes he has witnessed larger buildings burn because of faulty
wiring of only low voltage systems (it was a small office telephone company
that messed up).


Subject: Re: Q: Building a small machine room?  Materials/costs/etc.
Date: Wed, 17 Sep 2003 14:23:09 -0700

>   a) Thermal kill switch.  You may well want the room to be equipped
> with one.  This is a thermostatted switch that kills all room power if
> the ambient temperature exceeds some threshold, e.g. 90F.  The idea is
> that if AC fails and you don't get down there to shut down nodes fast
> enough, the kill switch kills power all at once rather than permit the
> nodes to overheat to where they physically break (as they will if they
> get hot enough).

Don't have the kill turn off ALL the power.. Only turn off the power to the
computers, but leave the lights and some receptacles alive.  More than once,
I had to stumble around in a computer room that was totally dark after
someone hit the Emergency OFF accidentally.

Bear in mind that if you have all that fancy UPS gear, the kill switch needs
to turn off the output of the UPS, not the line side.  There are actually
code requirements for some installations (mostly aimed at helping out
firement, who don't want to hit the Emergency OFF, and have the equipment
still energized).  This will typically be done by things like "shunt
trips".... your competent A&E person should know what's supposed to be done.

You also don't want the thermal kill to shut down the power to the blowers,
now, do you?

There are books on computer room design around, and while not everything is
applicable, a lot is.  It might be worth finding one at the library or
technical bookstore and browsing through it so that you can be an "educated

Andrew Latham

Penguin loving, moralist agnostic.

LathamA.com - (lay-th-ham-eh)
lathama at lathama.com - lathama at yahoo.com
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