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    Low Voltage in Electrical Service Panel

    In one of our buildings I was shown an electrical service panel that has inside the door a separated side channel. In that channel a Low Voltage (Category 5) patch panel has been installed. I have never seen such a thing and wonder what the EMI in there must be like for the network devices connected. Beyond the interference, is it within code to have Low Voltage collocated in an electrical panel? They tell me this was installed in the 90's. I've been searching the NEC and can't find my answer there (yet). Thank you very much for your help.

    #2
    Can you shoot and post a couple of pics?
    Master Electrician
    Electrical Contractor
    Richmond, VA

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      #3
      I have attached a picture of the electrical cabinet. There is a Cat 5 patch panel on the right. Thank you for your help with this.
      Attached Files

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        #4
        Okay, pic helps.

        There is no interference concern because (a) there is metal between the two compartments (also addresses voltage concerns) and (b) 60Hz provides little problem for ethernet signals.

        Those UTP cables might be for control wiring.
        Master Electrician
        Electrical Contractor
        Richmond, VA

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          #5
          Thank you Larry. My first concern was whether Low Voltage could even be in that cabinet. I guess with the metal separator it is OK. I also see in the photo that the Cat 5 and electrical cables are coming in through the same bushing. I don't think they are sharing a conduit. But I didn't look that closely when I was there.

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            #6
            EMI, even without the divider (which you can't do) isn't an issue but that panel itself is very interesting. I would like to see a picture of the label on the inside of the door to see who the manufacturer is and if it says anything about that LV section and is it really supposed to be there. What does it provide power to? HVAC maybe and the LV is for building automation? Maybe made by some HVAC manufacturer?

            -Hal

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              #7
              My guess it was made for a specific application and isn't a general use kind of thing.
              I live for today, I'm just a day behind.

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                #8
                I'd call that a cabinet within a cabinet.
                Master Electrician
                Electrical Contractor
                Richmond, VA

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                  #9
                  Thank you for the help guys. i really appreciate the insight. I have attached a photo of the manufacturers label. I hope this tells whether the collocated patch panel can be there. And yes, the patch panel supplies cameras, and temporarily installed Wireless Access Point locations.
                  Attached Files

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                    #10
                    No idea what it's for, give us a clue. Twist locks in and out, looks like some kind of PDU. Pacific Power Prod apparently has changed a lot and don't show anything like that. They do make PDU pedestals for mobil home parks. With 3 phase, all I can think of here is a hookup for refrigerated "reefers" at a ware house.

                    -Hal

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                      #11
                      Sorry. I'm not exactly sure what you are asking. There is no PDU there. The building installed this patch panel simply as an available cabinet location to house low voltage Ethernet connections. It looks wrong and out of place to me. I am trying to figure out if it is an acceptable installation within NEC. Maybe it was OK in the 90's but not OK now. Or maybe it is just fine since there is a metal barrier between the low voltage and high voltage circuits. I can't find an applicable code after spending a lot of time searching.

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                        #12
                        I still say that the inner cabinet is "the" electrical cabinet.
                        Master Electrician
                        Electrical Contractor
                        Richmond, VA

                        Comment


                          #13
                          Originally posted by rgnkenpo View Post
                          Sorry. I'm not exactly sure what you are asking. There is no PDU there. The building installed this patch panel simply as an available cabinet location to house low voltage Ethernet connections. It looks wrong and out of place to me. I am trying to figure out if it is an acceptable installation within NEC. Maybe it was OK in the 90's but not OK now. Or maybe it is just fine since there is a metal barrier between the low voltage and high voltage circuits. I can't find an applicable code after spending a lot of time searching.
                          The drawing shows twist lock receptacles along the bottom of the cabinet, one for each 3 pole breaker. That would indicate that this cabinet was intended for the connection of portable cords to some temporary equipment. Could be reefers in parked trailers as an example.

                          At any rate, you are you saying that you know that this patch panel was installed in this cabinet by someone from the building who was just looking for a good place for it?

                          Originally posted by LarryFine View Post
                          I still say that the inner cabinet is "the" electrical cabinet.
                          Yes, probably, but I suspect that that side gutter had a legitimate purpose in the design of that PDU like the feeder wiring. Have the twist lock receptacles been removed? I suspect yes since you would have noticed them.

                          If so, these modifications would void the listing of the panel. IMO it shouldn't even be used for an electrical panel.

                          -Hal

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                            #14
                            Thank you so much guys. hbiss, sorry I misunderstood your comments. I see what you are saying now. Hal, and Larry Thank you. It does seem to make sense that if PDU's were involved that the side channel would feed those. I'm not sure exactly where we stand on this installation being acceptable use and within code. But I think it is troubling enough that if we intend to use that patch panel it should be removed from this cabinet and reinstalled in it's own nearby NEMA box. I very much appreciate all of this help. You guys are really great guys. Thank you.

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                              #15
                              What if anything is supplied by the "power components"?

                              Looks like something originally designed for some other application has been "re-purposed" either partially or even entirely.

                              If this were designed for security/communications it maybe would have some 5-15 receptacles for powering some components, but those three pole breakers and 3p 4w locking receptacles sort of say this was originally for something else.
                              I live for today, I'm just a day behind.

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