I need to extend a USB device from a corner of my room to the above the fireplace. Since I'm already going to be installing some HDMI and audio cables through the wall, I'd like to have my USB device run through the same wall plate; I'm not having any luck determining if it's safe to do so, whereas it's quite easy to find in-wall rated HDMI or speaker cables. Would this extender be safe to run through the wall?

  • How long is the cable run?
    – Craig
    Apr 20, 2012 at 20:13
  • if the wire carries less than 30 Volts and less than 100 Volt-Amperes, you should be fine.
    – Tester101
    Apr 20, 2012 at 20:28
  • These extension cables have active components to regenerate the signal. Would they be allowed in a wall? My gut feeling is no -- but I don't know.
    – Craig
    Apr 20, 2012 at 22:38
  • I'm looking at that exact cable. The item i would plug in is only a foot long, and is only going to hold an IR receiver. I am only concerned about it being safe.
    – Scott
    Apr 21, 2012 at 13:22

5 Answers 5


If you are going in-wall over 16 feet, you need an active extender as many have pointed out. One alternative to this is to use a Cat5 extender: this allows you to run Cat5e/6 in-wall (riser or plenum cable is rated for in-wall use), then convert to USB at both ends as needed. One I found at Monoprice is rated for 150ft.

enter image description here

  • 5
    The downside to these is that you are restricted to USB 1.0/1.1 device speed, but for my needs (a single IR receiver), I'll be fine.
    – Scott
    Apr 24, 2012 at 12:59

If you are using USB 2.0 and your run is more than 16 feet, then I would suggest not to run it. USB 2.0 standards specifies that the maximum length to be not more than for 5 meters (16.4 feet). USB 3.0 does not have a length rating but the wire gauge (26 AWG) limits it to 3 meters, or 9.8 feet. Source is from Wikipedia.

EDIT gregmac is bang on with running the cat5. 0A0D is right about the safety end. It's like speaker wire in wall. You can not run just any speaker wire in the wall, it has to be in-wall rated. As for the extenders in the wall, I really don't think any wiring, even low voltage with coupling or connectors that are not accessible should be run in the wall.

The reason I like gregmacs answer is that cat5, with the right connectors can be used for a multitude of things.

  • Downvoting as this doesn't address the real question of whether or not it's safe to run in the wall. Will gladly upvote if real question is addressed.
    – Scott
    Apr 23, 2012 at 12:43
  • 1
    @Scott you are correct in downvoting as it really didn't answer. I just took it for granted that you could read my mind. Even tho I was the recipient, I encourage more downvotes as long as the explanation is just and comment explaining why.
    – lqlarry
    Apr 24, 2012 at 0:16
  • 1
    @lglarry Removed donwvote with edit. The real reason I asked is, there seems to be no real distinction for USB cables for in-wall use (optical cables are another which have no rating, and I'm sure I could find more if I needed to).
    – Scott
    Apr 24, 2012 at 12:36

I wouldn't run USB cable in a wall if it is not rated for in-wall installation. You could release toxic smoke or cause a fire if not done correctly.

One option you may not have considered is a Wireless USB hub. It's less intrusive and works well depending on what you are planning to do.


  • 3
    Low voltage wire is not going to *cause a fire. If a fire does occur, however, and the jacket on the cable isn't plenum rated, and the fire reaches the wire, then yes you could release toxic smoke. But then riser-rated Ethernet cable is fine for in-wall installation, but not okay for installation in areas that require plenum-rated cable. That's because plenum-rated wire/cable has insulation that burns slower and releases fewer toxic/acidic gases. I think people are probably getting their terminology a little mixed up, here. Nov 24, 2014 at 6:56

Generally speaking, most low-voltage wires are OK for behind-the-wall wiring.

  • Any sources which state this?
    – Scott
    Apr 23, 2012 at 12:47

Is it safe to do run USB in the wall? Yes. Does it follow the standard? Possibly. The standard sets the limit at 5 meters, so if it is less than that then you should be good. USB is notoriously testy about current flow. While it may work for your current setup, when you try the new USB 3.0 at high speed you may get some nasty data loss. Not to mention the EMI from the other cables. If you insist on running it through the wall use a high quality cable that is shielded. If you need more technical info the full spec is here Good luck!

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.