Why do we use facilities with EPO's?

Wed Jul 25 18:10:48 UTC 2007

On Wed, 25 Jul 2007, Leo Bicknell wrote:
> What I found interesting is that a single EPO is not a hard and
> fast rule.  They walked me through a twisty maze of the national
> electric code, the national fire code, and local regulations.
> Through that journey, they left me with a rather interesting tidbit.

Well.....

An Emergency Power Off button is a NEC (the electrical code adopted in 
most of the USA) trade-off for allowing more flexible wiring practices in 
computer rooms.  If you don't use any of those alternative wiring 
practices, you aren't required to install an EPO (modulo the rare local 
code variation). The problem is some people want to get rid of the EPO, 
but also want to keep using alternative wiring practices.

If you've looked in many computer rooms, you'll see some creative wiring 
practices in use.

You'll notice Telco central offices don't have building EPOs.  Likewise 
Equinix data centers don't have EPOs.  But they have limits on what 
wiring practices can be used in their facilities compared to other
data centers.