ECN Forum Forums General Topics of the Trade Voice - Data - Video Discussion More than 2 90's?

Often, if we do not do the total install, we will get the winning bid for Electrical, which will often include some conduit for Tel/Data. So many of them have what I think is a far fetched interpitation of some of the telecom standards of pulling in conduit. i.e. The 2 90 rule... they wont pull in more than 180 degrees of bend, reguardless of fill.

So yesterday the Cablers show up, and I have to tell them the Arch would not allow extra pull boxes in some of the closed walls, and some of them have 3 90's His reply was, "We won't pull it! It damages the cable. And it's code." My reply, "What Code, I challenge you to find one." He only has 3 cat 5e cables in these 3/4" conduits, so I say, "Try some lube." His reply, "Oh, that damages the cable jackets too."

I have an idea where this comes from, an outdated TIA 568 standard (Not a Code) that was a little far fetched, and didn't differentiate fiber optic from copper cabling.

Just wondering if anyone had any thoughts on this?

Mark,
I'm not at all familiar with the standards, but can tell you that the 180° "dream world" predates the use of fiber optics.
I can remember hearing about it in '70.

Here I was thinking it was new.... I was born in '70!

I have seen this often in specs. but I've never seen anyone get bent about it.

well i would rather not have alot of J-Boxes
in my big backbone and interduct pulls
you can always put another wrap on the tugger and use Lots of Lube.
sounds like pure lazyness to me

I would be interested to hear if anyone has actually ever damaged a cat 5 cable due to excess pull strain and under what conditions that occurred?

Would you even know if you'd damaged it? You'd probably have to ping it out with a TDR to find out. With the error-recovery mechanisms built into comm protocols, the user likely isn't going to realize what's going on, either--he'll just have slower network performance than he would have had if there was no damage.

Graphic TDR it would still be realy difficult to tell I think, unless you printed out each pair before you pulled as a refferance. I'm sure someone with too much time on thier hands can cut to length test and install to check it again, like in some testing lab. However I can say that most Certification meters will test exactly the same before and after. (With the same termination.)

With pulling tension of 25lbs max, you could bundle a dozen or so and swing like Tarzan..... Kidding

Here at the large public agency I work for in the Los Angeles area, when we award contracts for the installation of conduit to be used for data lines, we specify no more than 2-90's between openings. Nothing to do with code. Our IT techs who pull in the cabling later (fiber or cat-5) don't care if the openings are pull boxes or condulets, they just want easy pulling. Personally I don't think they have a tugger available, and wouldn't know how to use one (they aren't wiremen).

Radar

Don't think you would want to use a tugger with those cables.

Personally I think the "2 90" requirement is silly. I can't imagine how you could comply in many situations. No reason that you can't upsize the conduit and use a lubricant if necessary. Never heard of a lubricant damaging a cable by the way.

Maybe you need to rethink allowing IT techs with no experience doing this type of work.

-Hal