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May 19 / Greg

Conduit Standards For Datacom Cabling

We as IT guys don’t often have to think about cabling, let alone what the bend radius is supposed to be for fiber cable going through EMT (Electrical Metallic Tubing, Aka hard conduit). Well, I found myself with the question of what should be bend radius be on 3″ EMT for fiber instillations. I found this article from Lan Shack. It gives you the formula to calculate all this goodness for fiber as well as your standard ethernet cables. I also didn’t realize that code covered how full a conduit should be…did you? This article covers fill ratios also and even adds tidbits left off of the standard papers!


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  1. KEN / May 19 2010

    ANSI/TIA-568-C.3 10x cables O.D. Not under load 20x O.D. under load. Good rule of thumb is if you bent your conduit till it has a kink in it, the bend radius might be too tight for the fiber. Try to always use a conduit 10x the O.D. of the fiber and you should be safe.

  2. Greg / May 19 2010

    Well as I live and breathe…Kennith “the rigger” Berry. That sounds like a pretty good rule of thumb…hehehe

  3. omegatron / May 20 2010

    At the last AusNOG conference here in Oz there was a presentation on building fibre networks, with a particularly scary photo displayed of a bunch of fibre that was bent to far, heated up and melted the sheathing around it.

    Page 6.

  4. Greg / May 20 2010

    I like it…well…the article, not the picture…hehe

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