I've always wondered who died or was injured and caused the EPO to
come in to existence. There have been lots of "EPO caused downtime"
stories, but does anyone on the NANOG list even have one single
"Thank God for the EPO" story? I'll feel better about the general
state of the world if I know that the EPO actually has a real valid
use that has been ACTUALLY PROVEN IN PRACTICE rather than just in
-Jerry <----Is so anti EPO, he has no remote EPO buttons, and even
has the irrational fear about the jumper on the "EPO terminal strip"
inside his UPSes coming undone.
A friend of mine is a volunteer firefighter (and ex-ISP CEO, used
to be on the list). I'm not sure that he'd voluntarily enter
a burning datacenter to put it out if there wasn't an EPO.
Firefighters won't use water on live electrical fires.
If your response plan to a fire in the datacenter is "the building burns
down and hope nobody's inside it still" then you're set.
I've seen someone electrocuted and frozen on the wire in a non-datacenter
setting; we flipped the building breaker, which was further than
an EPO would have been. It wasn't through his chest, and was only
110 V, so it probably didn't make a difference that it took a
minute to turn it off instead of 10 seconds. There were no severe
I've seen equipment catch on fire in a datacenter. If I hadn't
been able to cut off the power locally, the EPO was the last
line of defense...
People I know have hit the EPO when sprinklers discharged in the
If you're lucky these won't happen to you. But that's not why
safety rules are put in place. Unluck happens.
-george william herbert