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EPO for In-Row Cooling (IRC) units

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    EPO for In-Row Cooling (IRC) units

    Hello Everyone,

    I need to provide an EPO switch located by the door to shutdown the power to the IRC units and a panelboard serving IT equipment (via shunt trip MCB). The IRC are provided with a remote shutdown terminal and is rated at 75VA -24VAC. My question is, how I can use one EPO switch to kill the panelboard and IRC's? The shunt-trip breaker will accept 120V and the IRC's will accept 24VAC. Do I need to provide a step down transformer (120V-24VAC) to shutdown the power to the IRC's?

    Thanks,

    #2
    I copied this from a Liebert manual. Looks like for this unit at least, you need a NC switch that opens to shutdown the unit. it would appear the unit generates the 24 VAC interrogation voltage. You would need a separate dry contact for each unit you need to shutdown. if you have a bunch of them a few realys would handle it.


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    Bob

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      #3
      In the old days I generally had an EPO control panel that could be shut off for maintenance.

      But it I don’t know anyone that uses 645 anymore so I haven’t used an EPO in a long time. Are you sure you need it?
      Ron

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        #4
        Originally posted by faresos View Post
        Hello Everyone,

        I need to provide an EPO switch located by the door to shutdown the power to the IRC units and a panelboard serving IT equipment (via shunt trip MCB). The IRC are provided with a remote shutdown terminal and is rated at 75VA -24VAC. My question is, how I can use one EPO switch to kill the panelboard and IRC's? The shunt-trip breaker will accept 120V and the IRC's will accept 24VAC. Do I need to provide a step down transformer (120V-24VAC) to shutdown the power to the IRC's?

        Thanks,
        This is easy enough to do with a relay with a 120 volt coil. Just run the 24 volt cooling unit circuit through the relay contacts.
        But as Ron mentioned, why are you using an EPO and in the first place? Are you designing to Art 645? Many operations forbid them today.

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          #5
          An EPO is not required by any code for these spaces and we are not running any wiring per NEC 645, it was the fire marshal (AHJ) for an Air Force base that who has requested the EPO. He wants to treat any space with a server rack(s) as ITE room and to comply with NFPA 75. None of the spaces even have a raised floor. It was a last minuet request before the final design go out.

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