Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

We've just re-wired our Sales Office using Cat 6 cabling into a new data rack. The cable loops down at the base, in case we need to use that slack in the future to re-terminate it, or to cover any other eventuality. This spare cable currently sits at the bottom of the rack.

In our old data rack, we have a rack mounted APC UPS. It's proximity to our Cat 5e cabling has never concerned us before, but since we've gone to the cost and hassle of installing new cabling throughout, we're making a concerted effort to ensure that we keep electrical interference to a minimum.

If we move our UPS into our new data rack and sit our UTP Cat 6 directly on top of it, could it cause electrical/magnetic interference or is there some sort of shelf that we should install to maintain a minimum separation? Or is it advisable to keep UPS's out of data racks?

share|improve this question

So long as the UPS has it's manufacturer recommended:

  • Shielding (usually just the metal case, as it came)
  • Grounding (usually part of the UPS's power cord or an external grounding lug)

you should be fine (assuming the equipment isn't horribly defective). I have 100'+ runs of Cat5e along 220v line, sitting up against the back of the UPS (cabling enters the cabinet at the bottom, where the UPS sits). Never had any sort of issues with any of it.

On a side note, I hope you mean Cat6a, as Cat6 is no faster than Cat5e (1Gbps). Cat6a can do 10Gbps.

share|improve this answer
Thanks for your answer, Chris. I've been trying to find something official on the UPS's documentation but it doesn't say anything about the casing providing shielding or a minimum recommended proximity. That would make sense, though. On your side note, our cabling is for workstations which have 100/1000 Ethernet cards. Our users aren't bandwidth hungry and probably don't need more than 100mbps. We chose Cat 6 for the price and ease of installation. – Matty Brown Jan 3 '13 at 11:05

I would avoid sitting loops of unshielded Cat6 right on top of a powerful AC current. It's not going to completely kill the signal, but it's not going to do you any favors, particularly if you need to get at or above 1Gbps throughput.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.