Plenum Rated HDMI CL2P 40 ft Cable, UL Rated, High Speed with Ethernet

Sewell Part # SW-29999-40

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About Plenum HDMI Cable

Pass Fire Code with CMP Plenum-Rated HDMI cable. Sewell's Silverback P4 series plenum HDMI line doesn't sacrifice HDMI conductivity to pass fire code in commercial buildings, employing 24 AWG robust conductors.

plenum hdmi cable

Commercial building codes require plenum rated cable for use in all plenum spaces. This cable is a must-have for installers working in any commercial building including office buildings, shops/stores, schools, universities, government buildings, and hospitals.

The plenum space above dropped ceilings and under raised floors is the optimal place for routing communication and A/V cables but since that space is also a vital air supply for people in the room below, it is required to use cable with low-smoke and non-toxic particulates in the event of a fire.

These Sewell Silverback plenum rated cables provide the ideal solution for any situations where cable needs to be run in a plenum space. This Plenum cable is ETL (Intertek) rated and meets all the specifications for full 4K (depending on your source and environment, a booster or repeater may be needed).

Plenum Cable is Required for Fire code

Plenum cable is a requirement by the National Fire Protection Association for use in plenum spaces. This cable must pass rigorous fire safety testing to be plenum rated.

Good Results Rely on The Cable but Start at the Source

Great high speed HDMI cables with 4K and 3D support, Ethernet channel, and audio return channel don't have to cost a lot. After all, cables are really just pipelines for AV data to travel, and the success rate often depends on the strength of the AV source.

Plenum cables tend to be long. This plenum HDMI cable has been tested to 4K successfully in an environment with average EMI. In situations where EMI is high, or when the AV source is not producing a strong signal, we suggest the use of a booster or repeater to get the desired results. 1080p at 60Hz refresh rate is usually possible over 50 feet of Silverback P4 cable without need of a booster or repeater.

Smart and Inexpensive Ways to Avoid Buying a Booster or Repeater

So, since great conductivity requires a good cable, we do everything we can to try to prevent you from needing a signal repeater, but sometimes even a perfect cable won't make up for a weak signal source or abnormally high volume of EMI.

One of the main things that prevents good HDMI conductivity (whether a plenum cable or normal CL2/CL3 cable)is electro-magnetic interference (EMI). Interference comes from both outside and also from within the cable.

The interference that your HDMI cable gets from the outside environment is usually from things like power lines, wireless devices (like wireless network routers), and even the flourescent lights in the office and the ballasts that power them (which are often snugged up against plenum spaces in most office buildings). We deflect this environmental EMI by employing both foil shielding (good for blocking high-frequency EMI) and braided shielding (good for low-frequency EMI). We employ 2 layers of foil shielding, one around the individual twisted conductor pairs and one that wraps around all conductors.

cross-talk in HDMI cable

Interference can come from within and this phenomenon is called 'cross talk'. Copper conductors are good at conducting your signal, but there is also signal leak which can collide with other conductors in the cable and disrupt the unique data packets that are being sent down each individual conductor.


For this reason, foil-shielding individual pairs is important, but an even less-expensive way to block inner cross-talk is to twist the conductor pairs within the cable at a precise rate that deflects the maximum amount of cross-talk.

Cost savings is not the only benefit of smart precision manufacturing; you also get the benefit of using thinner conductors in order to pass crystal-clear high definition results.


Sewell's Silverback P4 series CMP HDMI cable includes the following capabilities:

HDMI Ethernet Channel: Allows you to use HDMI devices that are IP enabled such as HDTVs and Blu-Ray players with Ethernet enabled features. This would allow you to use your Netflix instant viewing app on your new Ethernet enabled HDTV, for instance.

Audio Return Channel: Allows you to connect an HDMI TV with a tuner to an audio receiver via HDMI. This allows you to send audio from your TV to the receiver "upstream" without giving up the "downstream" video from a video source connected to your receiver (like from a Blu-Ray player or gaming console).

3D Support: This cable has added 3D support, supporting every brand and type of active and non-active 3D protocols.

4K support: This cable supports resolutions that far surpass 1080p (4096×2160 to be exact, 1080p is 1920x1080). For lengths 35 feet and longer, HDMI spec recommends the use of active boosting/repeating to achieve full spec.

Content Type Control: Your HDTV can now tell what is connected to it (for supported devices), allowing it to automatically adjust settings to best reproduce your video source's resolution, color setting, and more.

Additional Color Spaces/Spectrums: There are some colors that the RGB spectrum does not include, and many of these color spectrums are being incorporated in digital still photography and other applications, such as sYCC601, Adobe RGB, and Adobe YCC601 color spaces.

If you need more cables or a different length, view our HDMI Cable selection.


Mfg. Part Number

  • SW-29999-40


  • Sewell


  • Plenum Rated
  • ETL Certified
  • Certified HDMI cable
  • 1080p 60Hz maximum at 35 feet
  • 100% Digital (Audio & Video)
  • No compression, no conversion
  • HDMI High Speed with Ethernet (NEWEST VERSION)
  • 340MHZ /10.2Gbps bandwidth
  • 24 AWG
  • Audio Return Channel

Other Technical Info

  • All your HD video and audio in one cable
  • Uncompressed high-definition video
  • YUV color space support


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Plenum Rated HDMI CL2P 40 ft Cable, UL Rated, High Speed with Ethernet