• Inexpensive, Innovative School Device Cabling Solutions That Meet Fire Code

    I've been working K12 technology for over a decade now and have had the joy (and pain) of going through renovation of existing school buildings as well as construction of new ones.

    One topic I've recently experience some growing pains with has been device cabling, specifically projector cabling. We recently renovated one of our schools which involved totally gutting one side of the school, while the other side was torn down and re-built. Needless to say the process involved tendering network wiring etc... Similar to many other school divisions, we have interactive white boards and projectors in many of our classrooms. All of our existing schools use Category 5e network cabling. For some time now we've been using SVGA or DVI to Cat5e converters in many of our existing schools to connect teacher computers to the projectors in their room using in wall Cat5e wiring. Thus far it has worked quite well. Unfortunately, we found that the transition to Cat6 was not so smooth. You would think that the signal would be improved over the superior Cat6 cabling, but our results showed a decent number of rooms had noise problems using the converters over Cat6.

    The issues were hit and miss and also somewhat dependent on the converters used, some converters used worked just fine via Cat5e, but not so well on Cat6. The cost of the converters coupled with the issues made it less feasible to continue down this path with converters over Cat6.

    So what to do now? Pulling standard molded SVGA or DVI cable through conduit is not very feasible either due to the size of the ends. If you're going in wall with the cables as well (as most are) you must make sure that the cable meets local fire codes (in the USA, CL2, CL3 etc...). In Canada, it's even more difficult because cabling must meet Canadian fire code (CSA FT-1, FT-4, FT-6). Cabling that meets fire code is expensive enough as it is, but couple that with device cables that are conduit ready for pulling, and you have a very expensive recipe.

    Conduit ready device cable was something I had not seen before. For example, a 50ft conduit ready SVGA cable would have about 47ft of cable, with a SVGA connector on one end and a small round DIN connector on the other to pull through the conduit. It also includes the remaining 3ft of cable with the other DIN and VGA connector. The DIN connectors will fit through conduit as small as 3/4" in many cases which was perfect for our needs.

    I found several vendors selling conduit ready SVGA cable. But just about all of it was only CL2 rated (which is no good for Canada) which also requires an FT-4 rating for in-wall (non-plenum) applications. The prices were also quite steep for this specialty cable.

    I was about to give up, and then I stumbled across a company called AWG Cables in the USA. They had conduit ready cable (good), it was CL2 AND FT-4 rated (great), and a 50ft SVGA cable cost me just under $50.00 U.S. (Fantastic!). For a public school division on a limited budget, this was a great find that I had to share with all of you!

    I purchased these SVGA cables:




    After getting a complete price list, I noticed they also sell transformable cable solutions, which is just a generic cable you can install which then allows you to pick and choose what type of adapters you want on either end of the cable (SVGA, DVI, HDMI etc...). The transformable cable solution is more expensive than the SVGA cables, but in the long run would most certainly be the way to go. For this pilot test, I ordered a few of the inexpensive SVGA mostly to ensure the shielding was adequate and the din connector was indeed small enough to fit through our conduit. The cable fit through the conduit with ease (our conduit is roughly 1"). In future applications, I will likely plan for 100% TransConn cable.



    We recent installed the first of these cables and it cured our issues and has been performing flawlessly. We have a handful more to install and I will post follow up results as well.

    So what's the difference between Cat6 with transceivers vs. a transformable cable where you choose an end? Well, by the time you add up the price of transceivers and Cat6, the pricing probably won't be that much different (perhaps a bit more expensive for the transformable cable). But the big difference that I ran into head on in this project was likely the shielding factor. The quick-snap SVGA and transformable cables are shielded where as most Cat6 is not, and if you're running the cable near fluorescent lights or any other source of interference, un-shielded cable has the potential to cause more problems. Again, in the future I'm leaning heavily towards the TransConn / universal cable which is shielded instead of Cat6 simply to diminish the headaches interference causes since the costs are comparable.

    Here is where I sourced the cable: http://www.awgcables.com

    Also, be sure to check your local state / provincial regulations as there are variations in rules. I am writing based on my experiences with Alberta codes and a colleague of mine stated that some other provinces actually require FT-6 rated cabling (even in non-plenum areas) in child-centric buildings such as schools and daycares.

    Regards,

    Ernest A.



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