Excelent read so true.

[fyretek]

News letter email, I don't know how many times i have had to tell sparky to NOT put in more than 2 90's in a run and they still do it, maybe this will should be required reading for all sparky's engaged in systems piping. Below is the news letter email we all got just recently, wanted to post it here because it is sooo true!


Pull Boxes and Feedback From BICSI Instructor

Mike:

In the August issue of the EC&M you had a question that asked about how far apart to locate pull boxes in underground nonmetallic conduit.

I realize the NEC doesn't really address many of the problems relating to low voltage cabling (Data Telecom) in reference to pull boxes etc.

I teach a BICSI program directed towards the installation of the Data cabling. The references we use are the Telecommunications Distribution methods manual and the Telecommunications Cabling installation manual. The recommendation in the manuals is that a pull box be placed every 100 feet or where 2 90's have been placed. Pulling CAT6 or CAT5E cable is restricted to 25 lbs pulling force whether one or 10 cables are pulled. Keeping to this limitation can be very hard if long runs are involved or too many bends are in place.

Many times the Electricians will run the conduit for the installation and we find more than the two 90's. After doing a class with one of the IBEW's one of the electricians pointed out to me that by code they could have 3 90's before having a pull box. This started to clear up some of the problems I would see when looking at jobs. I always stress to the students when working with an electrical contractor to explain that with the pulling limitations on the cable we need the additional pull boxes, fewer bends, and if possible sweeping 90's to ease the pull.

BICSI has a very good website at www.bicsi.org. As more and more of the Electrical contractors are getting into the low voltage field the manuals would be of great benefit as a reference when doing work in that field.

I enjoy your column and read it each month needless to say it has provided me with some very valuable information.

Thomas E. Martin
BICSI instructor
Prime Communications
Omaha, NE

 

[iwire]

Re: Excelent read so true.

Originally posted by fyretek:
News letter email, I don't know how many times i have had to tell sparky to NOT put in more than 2 90's in a run and they still do it, maybe this will should be required reading for all sparky's engaged in systems piping. Below is the news letter email we all got just recently, wanted to post it here because it is sooo true!

Fyretek, I will continue to put up to 360 degrees of bend in any telcom raceway unless the job specs say otherwise.

Unless it is in the specs. we will have bid to the NEC not BICSI requirements. I see no reason we should have to pay for extra pull points.

 

[Ed MacLaren]

Re: Excelent read so true.

This thread reminded me of the "good ole' days". We usually had to show the telecom guys how to get a fish through a conduit run.

Ed

 

[don_resqcapt19]

Re: Excelent read so true.

Pulling CAT6 or CAT5E cable is restricted to 25 lbs pulling force whether one or 10 cables are pulled.

I don't understand why the permitted pulling force on the cable goes down to 2.5 pounds when ten cables are installed in a raceway. If the cable can stand 25 pounds of force in a raceway by itself, then that same cable can withstand 25 pounds of pulling force anywhere.
Don

 

[roger]

Re: Excelent read so true.

Fyretek, why don't system installers invest in tension meters instead of letting BICSI's recomendation be gospel, even in short or easy pulls.

Now, would you please go back to This Thread and explain what you meant when you said

i know it's in NEC not to use plastic in the celing,

and

besides any real electrician would not use plastic on fire it's just not done...ethic's u know...

Roger

 

[dereckbc]

Re: Excelent read so true.

Thomas, I work for a telephone company and am familiar with BICSI standards, although most Telco?s use there own standards rather than BICSI. The problems you mention are well known in the industry, and are the result of BICSI and other industry standards are not enforceable by any authority having jurisdiction unless specified by contract. To get there you have to spell every detail out in a contract. Simply stating the installation shall comply with BICSI standards is incomplete.

It is the designer?s responsibility to detail the specifications, not the installers. As Bob pointed out if the designer only specified a 2-inch PVC be installed between point A & B with 25 category 6 type cable installed in PVC and terminated at both ends with 101 type terminal blocks at each end is insufficient. That only leaves the installer with NEC guidelines to follow. You received what you asked for. So if you want pull boxes, limit the bends and distances between pull boxes, and want the cable to pass TIA/EIA-566-B Level III test, you had better detail that in the contract specifications. If you do that, then the 25 lb pulling tension takes care of itself.

One more thought. As Don stated; why would a single cable need to be de-rated from 25 lbs to 2.5 lbs pulling tension when used in multiples of 10? Total pulling tension should rise to 250 lbs. It makes no practical sense.

 

[hbiss]

Re: Excelent read so true.

After doing a class with one of the IBEW's one of the electricians pointed out to me that by code they could have 3 90's before having a pull box. This started to clear up some of the problems I would see when looking at jobs.

I don't understand that statement at all. Sounds like neither one of these guys knows the code.

I don't understand what half as many bends and additional pull boxes are going to do for you anyway. If I'm pulling a run I'll pull straight through a pull box so what's it supposed to do? If these guys think that I'm going to pull the bundle out of each pull box, lay it out then feed it back in and do the same at the next they are crazy.

If you need to reduce pulling tension the answer is larger conduit with reduced fill and lube, not this.

One more thought. As Don stated; why would a single cable need to be de-rated from 25 lbs to 2.5 lbs pulling tension when used in multiples of 10? Total pulling tension should rise to 250 lbs. It makes no practical sense.

Yeah, I'd like to hear the explanation for that too!

-Hal

 

[don_resqcapt19]

Re: Excelent read so true.

Hal,

If you need to reduce pulling tension the answer is larger conduit with reduced fill and lube, not this.

Does the pulling tension really go down when using larger conduit? I don't remember the conduit size being in the pulling force calculations other than to determine the configuration that the cables will take in the raceway.
Don

 

[hbiss]

Re: Excelent read so true.

I haven't seen any calculations for pulling tension, I would be skeptical of their accuracy due to the many variables involved particularly with multiple runs of communications wire.

Based on my own experience, yes the fill can make a great difference. Consider that a bundle does not stay "groomed" even if you feed it in that way. A large inside diameter in relation to the bundle means the the bundle will contact less of the inside surface than say a 40% fill. Of course this is only true to a certain point.


-Hal

 

[frankc]

Re: Excelent read so true.

Doesn't the code actually allow 4 90's in a run? Or is that for power only?
There is no substitute for precleaning and prelubing a conduit run. Taking the time to clear the path is kind of like spray painting a car-it's all in the preparation. These preliminary steps will ease the pain of too much pulling tension.
Isn't the tension restriction a function of the way CAT 5 and 6 cables are made, with the defined twists along the way? Too much tension will stretch out the twists, and may cause kinks and distortion ,thus clamping frequency response.
It's not like the old days of tying the pullrope to the truck bumper!

 

[hbiss]

Re: Excelent read so true.

It's a maximum of 360 deg though I don't think there is any mention of it in chapter 8. So yes, that would be for power with no restriction for communications.

Minimal pulling tension applies to all low voltage cables. This is mainly because small gauge conductors can be stretched. It really doesn't have anything to do with CAT5 twists.

-Hal

 

[fyretek]

Re: Excelent read so true.

I'm back woot know your all thrilled lol, first the code does allow for 4 90's, yes. how ever the intent of the posting was for field experience, how many of you had had to pull solid f/a cable through 4 90's? or just under sized pipe for that matter? i have to do it on 99% of the jobs i work on because of the thought and and i think most of you guys will love this....it's cheaper, yep it's cheaper to run conduit how ever it makes sense to the guy installing it per code that is than him considering what has to be pulled in it and what it will be like.


iwire .........thanks go ahead and do what you are told to we all need to work.


Ed MacLaren.....good ole days? lol when was that 1955? welcome to the 21st century. please dont put more then needed 90's in a run, thats all i can ask of you.


roger...... when i was young and had no clue about codes but yet the mom and pop shop told me to do what ever to get the job done...and after getting spanked by the inspectors, it only made sense to pick there brains and also pick up the book and learn some things, and by doing so i found out you cannot install plastic boxes in a had lid celing for f/a so as a rule of thumb i never used plasctic for any application in hard cap celings no matter what system. hope that answers your question. if not i dont care lol.

 

[roger]

Re: Excelent read so true.

fryertek, why don't you bid and run your own conduit?

and after getting spanked by the inspectors, it only made sense to pick there brains and also pick up the book and learn some things, and by doing so i found out you cannot install plastic boxes in a had lid celing for f/a

Do tell, what article and section did these inspectors quote or did you read this in?

Do you even own a copy of NFPA 70 or NFPA 72 for that matter?

Roger

 

[iwire]

Re: Excelent read so true.

Roger how dare you question a BICSI teacher.

fyretek what is the point you are trying to get across?

So far the only point I have received is that you are arrogant.

Bob

 

[fyretek]

Re: Excelent read so true.

You guys make me laugh and your response are typical. just goes to show.

 

[roger]

Re: Excelent read so true.

While your laughing maybe you can look up and post some substantiation (from a code, recomendations have no real weight) to back up your statements, This will gain you some credibility.

You can simply type it word for word out of the code if do not have an electronic version to copy and paste from.

Cmon, give the young guys (well any of us) a reason to believe you.

Roger

 

[ryan_618]

Re: Excelent read so true.

Originally posted by fyretek:
You guys make me laugh and your response are typical. just goes to show.

It just goes to show what? That you are the only person who doesn't realize just how wrong you are?

 

[fyretek]

Re: Excelent read so true.

This topic was not only about the article but also about the way some things are done, you guys not being in the ibew and not being a system tech obviously do not understand the point of the comments, which is o.k. this post was not intended for you who are not in that end or side of the industry to understand. those of us who are know exactly what i am trying to get across and understand it. so if you are offended by my comments just relize that you are not the intended reader. Attacking me and my references only makes you look foolish and anti-forum everyone is intitled to there opinon.

 

[iwire]

Re: Excelent read so true.

Originally posted by fyretek:
This topic was not only about the article but also about the way some things are done, you guys not being in the ibew and not being a system tech obviously do not understand the point of the comments,

No I do not understand the point you are trying to make. So I am asking you nicely, please explain your point.

I am more than happy to follow both the NEC and any job specifications. If the job specifications said I must follow the BICSI recommendations I would do it without question.

I am not going to add costs to the job just because it would be 'nice for the data guys'.

I guess my real question is why you believe the company I work for should give material away for free?

You could always put in a NEC proposal to add the BICSI requirements to Article 800. Personally I do not think it would be accepted as what you want in my opinion are design decisions made into code.

So how about a real reply?

Bob

Edited some smiles in to demonstrate my good mood.

[ March 19, 2005, 01:35 PM: Message edited by: iwire ]

 

[pierre]

Re: Excelent read so true.

Long ago I was taught that in a discussion, when one person reverts to yelling or being obstinate, that meant the person felt (consciously or sub consciously) that they have lost their point of the discussion.
Fyretek, you are being obstinate.

I have been in the industry a long time (including IBEW training - for what that is worth) and IBEW or not, there are many here who have knowledge that is beyond what can be taught in a classroom setting. There are also many who are stubborn as mules and need great coaxing to turn their train of thought away from the way the have learned to the proper way.
Some of what you say has merit, and some does not. What you need to do is properly present what you have been trying to say so as to:
1. not piss these guys off
2. impart the proper information
3. Listen to some of these guys, as there is much "field" and "learned" knowledge here that may even benefit you.

EDIT:
I just read my copy of BISCI installation procedures for conduit pulls, and it does not mention the number of 90s. What it does outline is the radius of bends and possibly using "break away swivels set at 25lbs. It also gets into the setup of the pull, including reels, swivels, etc... to help ease the tension of the pull.

[ March 19, 2005, 04:51 PM: Message edited by: pierre ]