I'm running electrical conduit to metal knock out boxes throughout a new construction residential home. The knock out boxes are soley used for POE ethernet. Do the metal knock out boxes need grounded somehow? If so, what is the proper means of doing so?

Metal Knock Out Box with POE Ethernet Cable

  • The way I see it, there'd be no way to do it. The ground wire must be a certain size relative to the conductors. So what happens if somebody tries to use that box as a ground for something else? (Which is legal in retrofit work). What if the "something else" uses 10AWG wire but you only pulled a 14 AWG ground? You are better off with the box testing out as ungrounded, which is reasonable for data cables. In any case, be careful with PoE wire since the voltages therein exceed NEC's blanket definition of low voltage. Jun 16, 2016 at 23:20
  • FYI, we usually screw half the extension to the stud and not use the box.
    – Kris
    Jun 17, 2016 at 10:32

1 Answer 1


No, they do not need to be grounded.

If the box contained household voltages, then yes, it would need to be grounded.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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