So, you’re installing networking cables and terminating network jacks, and you need electrical power – of course.  But, how far do you separate them?  Technically, there’s no “official” answer, depending on who you talk with.  We recommend 6”, but the NFPA recommends 2” or more.  Other organizations recommend 6’.  Why is there a difference?

This has everything to do with interference and crosstalk.  Without getting too technical, when you run electrical current through a copper cable, it generates electromagnetic interference.  This interference can cause what’s called “crosstalk” in other nearby cables; basically, this this is when current going over one cable “creates” data on the second cable, or at least screws up the data that’s on that cable.  There are ways to compensate for this, and higher level technologies (on the OSI stack) can correct for some of this error condition, but it’s best if it’s not there to begin with.

So, the upshot?   If you’re running cable yourself, or directing someone to install network cabling, make sure you maintain at least a 6” distance between power and data, simple as that.  If your cables absolutely must cross, make sure they cross perpendicularly, not in parallel.  Oh – and if your budget permits, use shielded cable – makes life a whole lot easier and substantially improves connection quality.

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