North American Network Operators Group

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RE: Why do we use facilities with EPO's?

  • From: Tim Donahue
  • Date: Fri Jul 27 14:44:02 2007

On Fri, 2007-07-27 at 13:09 -0400, Barry Shein wrote:

> Also, NOT TO BE TOO LITERAL MINDED, but isn't the point of a UPS that
> it has a lot of power even when it's not getting any externally?
> Doesn't hitting an EPO on a UPS at best only reduce the electrical
> hazard of hitting it with water a little bit?

Not an engineer, and not a firefighter, but I think I can answer this

Yes, hitting the EPO would leave a lot of power potential stored in the
batteries in the UPS.

The point of the EPO is to isolate those batteries from both the
external (possibly high voltage) feed coming into the UPS and to isolate
them from the inverters, transformers, power points (plugs) and whatever
else is used in the build-out getting the power out of the batteries and
to the equipment. 

This achieves a couple things. 

* It potentially removes one of the requirements of combustion
(heat/energy input).  

* If the fire is not within/around the UPS itself, the firefighters can
avoid the power that is still in the room.

* Removes the power from the wiring below your raised floor so water
will not come in contact with the power present during normal operation.

I'm sure that there are others out there that could give you even more
reasons, but these are the ones that come to mind immediately.

Tim Donahue