I'm going to install a 2 gang junction box for behind my tv - one side will have an outlet and the other side would be for a funny pipe to pull HDMI cables thru.

I plan to use some flexible plastic conduit to do this, but I'm concerned ----since I'm getting this inspected-if it would be up to code to drill a ~1inch opening in one side of the plastic junction box to put my funny pipe through.

Does the (2019) NEC have anything to say about this? Is this a bad idea?

  • What sort of flexible conduit are you using for the HDMI cable? (ENT/"smurf tube"? flexible metal conduit? liquidtight flex of some sort?) Also, do you have a barrier for your junction box taken care of already? Aug 21, 2021 at 12:59
  • 3
    NEC says that your low-voltage (HDMI, etc) wiring must be separated from the mains power by a physical barrier if they're in the same box.
    – brhans
    Aug 21, 2021 at 15:43

2 Answers 2


They actually make boxes for behind TV's I would suggest you use one of those since they are designed to handle both. Almost any hardware store should carry at least one type of these. Take a look at the Legrand 2 Gang White Plastic New Work/Old Work Standard Rectangular Wall Electrical Box.


You're not allowed to mix low-voltage and AC mains cables in the same box, unless there is a listed divider (i.e. made to work with the box).

They actually make split boxes, which have an AC mains junction box on one side, and an open back on the other side intended for low-voltage whatever.

The "large diameter tube" passage you want is fine in principle, but you'd want a 2" diameter tube, and nobody makes normal 2-gang boxes capable of accepting a 2" conduit. Many installations simply leave the space open in the wall cavity. So you have to reach in and grasp around to find your cable.

However, they do make pre-assembled kits specifically for doing "hide-the-outlet" behind the TV. They are 2-gang: one side is indeed a large tube which they make as part of their kit, and the other side is an AC outlet up top, but an inlet down below. You run a short extension cord from an outlet to that inlet, after going through a surge suppressor, smart switch, whatever suits your fancy. See how clever that is?

Some of those kits simply open up to the wall cavity, so choose carefully.

  • 1
    Why 2" diameter? Just to fit the HDMI connector(s) easily? That's easy to work around by pulling a cable with mini-HDMI through and then adding a mini-to-ordinary HDMI adapter afterwards.
    – TooTea
    Aug 21, 2021 at 22:13

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