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We have an unfinished attic - the insulation-everywhere, step-in-the-wrong-place-and-fall-through-the-ceiling kind.

I'd like to run Ethernet cable through the attic. I know for Romex, I'd have to staple the wire to the joists, drill holes when running perpendicular, etc. However, I can't find anything stating I need to do the same with Ethernet. In fact, much of what I've read online implies there are basically no rules for Ethernet!

So I want to make sure:

  • Do I need to need to staple the Ethernet to the side of the joists? Drill holes when running perpendicular? Can I simply set the cable down along the top of the joists?
  • If I decide to use conduit (for future-proofing), do the rules change?
  • If I were to run the cable through the dropped-ceiling of a finished basement instead, would the rules change?
  • 2
    Personally, I run category 5/6 and coaxial the same way I'd run NM cable. Except that I don't put junctions in boxes. Same protection, same support. – Tester101 May 18 '14 at 1:36
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National Electrical Code 2014

Chapter 8 Communications Systems

Article 800 Communications Circuits

I. General

800.24 Mechanical Execution of Work. Communications circuits and equipment shall be installed in a neat and workmanlike manner. Cables installed exposed on the surface of ceilings and sidewalls shall be supported by the building structure in such a manner that the cable will not be damaged by normal building use. Such cables shall be secured by hardware, including straps, staples, cable ties, hangers, or similar fittings designed and installed so as not to damage the cable. The installation shall also conform to 300.4(D) and 300.11.

Chapter 3 Wiring Methods and Materials

Article 300 Wiring Methods

I. General Requirements

300.4 Protection Against Physical Damage.

(D) Cables and Raceways Parallel to Framing Members and Furring Strips. In both exposed and concealed locations, where a cable- or raceway-type wiring method is installed parallel to framing members, such as joists, rafters, or studs, or is installed parallel to furring strips, the cable or raceway shall be installed and supported so that the nearest outside surface of the cable or raceway is not less than 32 mm (11⁄4 in.) from the nearest edge of the framing member or furring strips where nails or screws are likely to penetrate. Where this distance cannot be maintained, the cable or raceway shall be protected from penetration by nails or screws by a steel plate, sleeve, or equivalent at least 1.6 mm (1⁄16 in.) thick.

300.11 Securing and Supporting.
Please see NEC for full text

So basically, you're going to want to protect and support the cables in a similar manner to any other cables. Curiously, the code didn't mention 300.4(A) Cables and Raceways Through Wood Members.. Though I'd likely still follow that section if I had to run communication cables through wood members.

If you run the cable through conduit, you'll have to follow the code for protection and support (fill requirements do not need to be met, per 800.110(B).

If you run through a drop ceiling, you'll have to install support wires for the cable, or support it in another approved manner. You can't support the cable using the ceiling grid, or support wires.

Here's a great document from Mike Holt that explains Article 800 (with images).
Introduction to Article 800 - Communication Circuits (PDF)

  • Thanks! Another quick question: I see supports like these all the time. I assume these fall under "cable ties, hangers, or similar fittings". I notice in the picture that they go along the upper-edge of the basement wall. Is this an acceptable workaround to avoid having to drill through the joists? – BlueRaja - Danny Pflughoeft May 19 '14 at 15:35
  • Yes, following the beam is a common technique in unfinished spaces, to avoid boring holes. Keep in mind, however, that if you ever finish the space, you may have to move the wiring. – Tester101 May 19 '14 at 15:48
  • @BlueRaja-DannyPflughoeft it looks like that "these" link is broken -- any chance you could edit it or put a new link to show? – Doktor J Jan 17 '17 at 4:56
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    @DoktorJ: I assume the "these" link is this (same catcr50 image name) – Pakman Jul 9 '20 at 17:47
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The rules for adequate protection of wires from damage, and "workmanlike" installation apply to low voltage (Class 2) cabling just as they do for any other electrical installation.

Yes, you need to have the cable well attached to framing, and it cannot be resting on a drop ceiling.

Conduit is not required, but can serve as both protection and support for low voltage cabling. "Smurf tube" or Non-metallic flexible conduit is often used for this. It is even available in an orange color to signify it contains low voltage wiring.

In general the rules are similar, but more relaxed. Most notably low voltage cables can have junctions exposed to air (not in a box.)

  • 1
    Orange Smurf Tube Electrical Nonmetallic Tubing (ENT) typically was used to protect OM1 and OM2 multimode fiber (MMF). Aqua smurf tube suggests OM3/OM4 laser optimized MMF and yellow smurf tube implies single-mode fiber is enclosed (SMF). In reality, you can get ENT in a rainbow of colors to match your feng shui decor aesthetics. If fire codes permit, instead of bending EMT or using Flex, use ENT to route AV and IT wiring during rough in (before drywall installed) to make cable installations smooth. – Jules Bartow Oct 16 '18 at 23:43
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Never posted on this site so sorry if my formatting is off but I noticed this post is still active. I was hoping after 5 years you have gotten the solution you were looking for but to shed some light on this in simple terms. Click on the link of the Mike Holt document on Article 800 of the NEC the other person posted. Reference these parts below:

800.110(A)(1) on page 75: calls out figure 800-24. At the bottom of the figure the text says "Communication cables aren't required to be installed in raceways." which means you don't HAVE to put the wiring in conduit. Sometimes it just makes things easier and/or neat. If you don't put in in a raceway/conduit you have to still support it though, via the section below.

800.113(B) on page 78: which basically tells you what you cannot do. But the author makes a comment, that states you have to secure the cabling to structural components of the building using things like straps, staples, cable ties, etc. that are designed to not damage the wiring. I am not 100% sure on the allowed "unsupported length" but I probably wouldn't go longer than 6ft if possible.

If you are looking for clamps; when I worked on aircraft, we had cable clamps p/n MS21919 that did a great job. They might be overkill for what you need though.

As for the smurf tube. Double check your village code. They might have adopted the NEC but then made amendments to it to not allow ENT (smurf tube). My village requires all wiring within conduit to be in EMT rigid tubing (I hope they only mean for power, and not communications but I have to ask). Also for the color of the smurf tube, I noticed someone else said orange was for communication. I know orange is used for communication when buried but I also look at the Carlon Catalog, page 3 in the "options" and they suggest yellow for communication. So I don't know what is right, only that I'm sure the color will mainly be for your reference only and as long as you know.

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