I have a client (I'm an IT consultant) that is building out a new office - they are a medical practice that is expanding, and so one of the things we are going to be doing is setting up a dedicated network closet with a rack for their server(s), etc. They are going to have a lot of stuff in there (several servers, network equipment, phone system, sound system, lighting system, etc.), and so my concern is getting the appropriate electrical in that closet.

I am not an electrician, and don't usually deal with electrical matters beyond UPS's (which they will also have), but I recall the electrician stating they were going to be putting a good amount of outlets in there as well as a dedicated circuit (or something similar - can't recall his exact words). When I went to look just now (it's mostly finished), all I see was one grouping of four outlets (similar to this, although not sure if they were 15-amp or 20-amp: https://image.shutterstock.com/z/stock-photo-a-plex-electrical-outlet-for-volts-in-north-america-165902273.jpg). To me, that seems like not nearly enough, and it would seem we'd probably want to make sure that whatever outlets were in the network closet were dedicated (or whatever the correct terminology is for that).

Am I off-base here? Can anyone shed some light on this for me so I can go back to the client, the contractor, and the electrician to get things squared away? Thanks!

  • You can get a rackmount PDUs that you'd plug into one of those outlets and mount it at the top of the rack, so all power just runs to the PDU. You can even get those that have displays so you can monitor amperage usage and other stats. That way you can ensure you won't plug more into the PDU than the circuit at the breaker can handle. – MaQleod Aug 14 '19 at 23:31
  • Thanks - that sounds like a good idea! But assuming the 4-outlets are just one 15A or 20A circuit, I'm going to be woefully under what I need for a network closet, right? – Marc NJ Aug 14 '19 at 23:47
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    This is outside of the scope of SU. However, you need to look at the input current rating of the equipment you plan to install to install, then install the appropriate amount of circuits, plus some extra for future. The amount of receptacles is meaningless. For example, if you have 6 network switches rated at 5 amps, and a server rated at 10 amps, you would need at least 3x 15 amp circuits or 2x 20 amp circuits. – Jason Aug 14 '19 at 23:57
  • It'd be hard to say without all the specs, but yeah, a single 15A circuit might give you capacity for two servers and a decent sized switch (roughly). You should lookup the power requirements for each piece of hardware that'll be plugged in to get a better idea. – MaQleod Aug 14 '19 at 23:59
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    The photo has 20-Amp receptacles. Determine if each receptacle is an individual circuit by shutting off circuit breakers one at a time, and checking which outlets go dead. – sawdust Aug 15 '19 at 0:33

You included a picture of a pair of 20A 120V receptacles, as sawdust indicated. They may well be on the same circuit, so you might have a total of 2400W (= 20A x 120V) of power you can draw from them.

You mention a variety of devices:

  • several servers,
  • network equipment,
  • phone system,
  • sound system,
  • lighting system,
  • etc.

The number of outlets isn't an issue (that is what PDUs (fancy name for fancy power strips) are for).

The amount of power available (2400W - 4800W) might be. You can definitely get an electrician to install more circuits / power.

If you use too much power in the room (more than the building's AC system can cool), the room will get too hot, and the equipment will fail when the room gets too hot. With what you described it isn't clear whether this room will fall into that category. You should be aware of that risk, and check in with the people in charge of HVAC for the building if you go significantly beyond what the electrician has installed already.

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