# EPO circuit in Data Center



## mshields (Dec 6, 2012)

I've got a client who has a 30kVA Powerware UPS for a server room.  He's also got a Pre-action system for this room.  Lastly he's got an EPO in the room and his pre-action system is tied into the EPO circuit such that if it goes off, UPS is disabled.

The problem is that once twice a year they are obligated to test the pre-action system and every time they do, they are actuating the EPO.  This is the first time I've ever enountered this.  Obviously there needs to be a bypass in the controls circuit such that you can test the pre-action system without shutting down the server room altogether.  What I'm not sure of is how this is best accomplished.  Is this something that the UPS vendor would have built into it's control circuitry.  Or do we need to create a by pass test switch that disconnects the signal from the preaction system to the UPS such that the system may be tested.

Would be very interested in any thoughts you might have on the subject.

Thanks,

Mike


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## globe trekker (Dec 6, 2012)

Is this a "new" installation?

Is the EPO the only means to shut down the data center   vs. multiple disconnecting means for

each system being de-energized ( all dedicated HVAC systems for the data center, all electronic

systems, any MOE systems, other?)

Did your data center use NFPA 75 as the construction standard, or non-rated plenum cable assemblies

below any raised floor areas?

An EPO may not even be required!

Also, check with the manufacturer of the UPS about any possible by-passes incorporated in to

their circuitry. Typically, most do not have a built-in by-pass.

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## globe trekker (Dec 6, 2012)

..additionally, there are alternatives to having an EPO installed. See Article 645.10

in the 2011 NEC, and as an aside, you might want to discuss having the EPO

removed entirely, with the local Fire Code Official (FCO), with approved fire

suppression & monitoring measures in place.

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## mshields (Dec 9, 2012)

I'm familiar with the whole idea of 645 representing an optional approach to data center rooms affording exceptions to chapter 1 through 4 providing certain features are built into the design most controversial among them being the EPO.  But this is an existing room with a raised floor with liquid tight flex under it so the EPO must stay.  I am looking into wether or not the UPS manufacturer has something built in.

Thanks,

Mike


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## chris kennedy (Dec 9, 2012)

mshields said:
			
		

> I've got a client who has a 30kVA Powerware UPS for a server room.


Power ware comes in a 30kva??? Power ware I have installed have by-pass.


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## globe trekker (Dec 10, 2012)

FWIW, I came across the following White Paper on EPO's & Data Centers.  Enjoy!

*http://www.apcmedia.com/salestools/ASTE-5T3TTT_R4_EN.pdf*



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