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I have an idea where this comes from, an outdated TIA 568 standard (Not a Code) that was a little far fetched, and didn't differentiate fiber optic from copper cabling.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

I agree, maybe the IT Guys should first learn the trade and then buy the tools to do it(fishtape). at my company we can even
run the conduit if need be and we can put up to 4 90's between boxs. but we try to leave that for the big burly electricans to do :-)

I am almost 100% sure (>96.90023417%) that I have seen an IBM Specification note regarding 180° Maximum, for scenarios involving Conduit runs and pulling in Type 1/2 STP Cables.

Of course, this was back in the 1980's (the terminology of Type 1/2 should date its self!).

Let me dig up some of the legacy documents to see what's up.

As far as anything modern (>1995 A.D.), I had been given the 180° Maximum specification on the first FDDI Backbone Install I ever dealt with - circa 1999 to 2000.
Technology of the Cable was likely the reasons for the Paranoia - and this Backbone's Conduit Runs were filled with Pullboxes!

Ran from/to/between NERs on 3rd, 6th and 9th Floors.

Outside of the loops involved with the Pullboxes, the Cable Pulls were extremely easy!
(1 Fiber Optical Cable in an 1¼" Conduit tends to be somewhat easy to pull - even without Aqua Gel!).
The same cannot be said about the actual EMT / Pullbox installations!
That's where the "fun part" came into play!


Scott35

Here's more. http://www.mikeholt.com/codeforum/ultimatebb.php?ubb=get_topic;f=9;t=000252

The 2 90% bends come from BICSI organazation, a telecommunication standard writing organazation. It is not associated with NFPA nor can it be enforced by an AHJ. The only way to enforce the requirements are by contract specifications.

I had that spec at a large popular theme park a few years back. I had a 4” run between the main telecomm. Room and a remote room (they did not refer to it as an IDF). It was a retail space with themed rooms through out. In order to miss the plumber, fit inside the building and comply with structural specs (like angle of oppose) I had to put 3, that’s right,3 90’s in the run!!! I decided to take a chance rather than write the RFI requesting a 3X5 concrete pull box inside there retail space (with the fancy custom concrete floors). I never heard any complaints about tough pulls from the data contractor. I am sure it will be fine for years to come. I think the 2 90 requirement is just an easy way to assure easy pulling. What is wrong with doing the pull calcs to prove <25lbs.??

I used to work for a contractor in the NYC area and we did all our own conduit work, my employer never specified anything about no more than 2 90's in a run and we sometimes ran up to 16 cables through a 1" emt with 3 sometimes 4 90's in the run (we definitely pulled pretty hard with plenty of lube) and we never had a line fail for any reason other than a swapped pair or bad jack.We subjected these lines to testing using our Fluke OmniScanner2 which tests for all of the specifications set forth by the T568B? standard.I from first hand experience have definitely got to say that this spec of no more than 2 90's in a run of conduit is got to be for ease of pulling.

I forgot to mention that it was a tel\data contractor that I worked for.

The only thing they have you on is not installed to spec. If it is speced for no more than 2 90's then what can you do. Kind of sucks but at least there are no wires in it so a can could be cut in easy enough.