I am running coax RG6Q to my FiOS box. I know to cross electrical cables perpendicular, but is there a limit to how many wires I can cross in a short area? See my picture: the coax is the black line going horizontally to the vertical power wires. Is this a disaster waiting to happen? Can I test the interference before I commit to this line?

coax perpendicular to power

Edit: I have been running this configuration for over two years now. I can say that I have experienced no noticeable degradation of signal during this time. Thanks!

2 Answers 2


If you cross perpendicular to the power there will be no problems no matter how many cables you cross each cable basically cancels when perpendicular.


Not only does perpendicularity eliminate interference, but also an important point of coaxial design is that any interference affects the core and shield equally, but in opposite polarity.

For the second question, yes. Hook up the coax to an oscilloscope and view the waveforms on different settings.

  • 1
    Well, no; the interference affects both conductors in the same direction; it's the coax signal which is carried in opposite directions. Either way the interference doesn't affect the signal (much). Jun 11, 2016 at 10:13
  • Yes, the interference is in the same physical direction, but the two conductors are opposite polarity in the circuit.
    – WGroleau
    Jun 11, 2016 at 21:08

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