conduit for fiber and copper 5

[fibervoicedata]

I would like to know if there is an actual code and/or rule (BICSI/NEC etc) which specifically details the rules to install amored fiber cable in separate conduit from CAT5 cables. We are going to begin a project which requires that all cabling be enclosed in conduit and someone forgot to include the costs for conduit for fiber and now we are being told to install it with the CAT5 cable. I've been told in the past that this is not acceptable but I would like to see the rules/codes in writing so that I can forward it to the General Contractor and Architect. Thanks in advance for any assistance with this.


Joe

 

[mikeydidit]

Not sure of any "codes" but i usually install our fiber in the same conduit but inside a 1 1/4 inner duct. This keeps the fiber and copper safe when pulling. Pull the inner duct first then the copper. Then the fiber through the inner duct. nice neat installation.

Hell, there are no rules here - we're trying to accomplish something.
Thomas A. Edison

For the best response to a question, read faq690-6594

 

[GMgerry]

Need a little bit more information.

What is the situation that you need to install Cat 5 and fiber in the same conduit, size? Is it feeding one area or location in a building? Generally if you are installing armored cabling it is outside the conduit. You can save a couple bucks by installing non armored fiber in the innerduct.

 

[fibervoicedata]

Thanks for the info. Also, I would like to add that the project installation is in a new school, designed for everything to be enclosed within 1" up to 2 -1/2" conduit for all cat5 cabling. The specified fiber is armored cable and the already installed conduit is not sufficient to allow innerduct. The GC and architect are telling us to put it in the same conduit. I don't want to break any rules and risk the end customer who happens to be the school district/IT dept come back and tell us it is not acceptable. The custome has already told us to not combine the two in the same conduit to leave it exposed but the gc/architect don't like it due to the aesthetics. Hope this clarifies the situation a little.

Thanks,

Joe

 

[mikeydidit]

I am not sure you would be "breaking any rules" but the purpose is to not skin any other cables while pulling. To begin with if they would read the 568A building "standards"
BICSI "recommends" that you use 4" conduits.

The price of the conduit size is very little vs. having to do it twice or in other words, not have enough conduit to hold what you need. This is the case here. The install price is where you expense lies. Either directional boring or trenches cost $$$.

The customer I am sure spec'd out armored fiber to protect their investment. Had they went one step further, they would have left room to pull in other things through their conduits and really get their moneys worth on their investments. But most customers don't know this, so they go to an architect thats not a RCDD and still end up with the same results. <end rant>

In your case I would pull both in the same conduit and you will be OK. Be sure to lube the cables, and not skin either. If the conduit are installed like they should be, you should have plenty of pull points and boxes, handholds Installed so the weight of the cable is not anther issue.

One thing to look for is the fill ratio. Make sure you do not exceed that. The fire marshal's office may not like it if you do.

Hell, there are no rules here - we're trying to accomplish something.
Thomas A. Edison

For the best response to a question, read faq690-6594

 

[mforrence]

It sounds like your concern is about the two co-existing in the same pipe... you should have no such concern. There are certainly rules about std AC and low voltage in same pipe, but not for all low voltage. Technically, even fill ratios don't apply. You simply must be able to pull all in without damage to other cables. I agree with GMgerry - armored cable within conduit is a waste of money. If you're going in the earth - even below a slab, the cat5 should be duct-rated (black jacket).
Mike

 

[buitenhek]

Mike, I am curious. Why don't fill ratios apply, technically?

Truly there are no "Conduit Police" just good install practice guidelines. And the fire marshal seems focused on conduit stub & fire wall sealing, not fill values.

I'm thinking the intent of the fill ratio was to:
1. prevent cable jams
2. allow space for future cable(s)
3. limit "stuffing"
4. standardize for the next guy (~end result)

Regards
Peter Buitenhek
ProfitDeveloper.com

 

[mforrence]

Fill ratio applies to high voltage and deals with heat dissipation. No need in low voltage apps.
Mike

 

[fibervoicedata]

Thanks to all for your feedback. I would like to add that an RCDD has indicated that there is something about armored cable causing interference with crosstalk/interference due to the metallics in the armored cable. I'ved looked it up in the TDMM manual but couldn't find it. Also, I believe that the TDMM manual has a reference to fill ratio which is 40% fill for 2 or more low voltage cables in the same conduit.

 

[mikeydidit]

The fill ratio has to do with the amount of cables in the conduits and the lack of enough room to apply the correct amount of fire stopping materials. To many cables and their is not enough room to properly fire proof the conduits.

Like fibervoicedata has stated, most call for a 40% fill ratio. This allows plenty of room in the conduits to use mineral wool,putty or whatever type of fire stopping materials you decide to install. This gives the fire stopping materials room to expand and seal the conduits if they were ever to get hot from a fire.

Here is a link that may help you on the fill ratios.

http://cr.ucdavis.edu/policies/CablingStandardsDec2000.pdf

Hell, there are no rules here - we're trying to accomplish something.
Thomas A. Edison

For the best response to a question, read faq690-6594

 

[mikeydidit]

fibervoicedata If I sounded short in my earlier post, it was not directed at you. It sounded like you were put in a position that I am way to familiar with working here. I have constant battle here trying to make them do things right. If i can catch them before they get their hands on it, I have a chance. If not them I have to straighten out what they screwed up.

So If i sounded like i was short with you, I may have just been having flashbacks from working here.

and good luck on your project.

Hell, there are no rules here - we're trying to accomplish something.
Thomas A. Edison

For the best response to a question, read faq690-6594

 

[technome]

Two cents...
Agree with mforrence, low voltage wires without power feed wiring in the same conduit, in most areas have no building codes applied.

If your going between two building, your major concern with CAT 5 should not be with conduit size but voltage differentials between the building in lightning storms. Grounded metal conduit, even if it is securely grounded to both building grounds, does not provide total protection from ground/building lightning hits; if there is ground potential difference between the building, lightning can possibly jump to the CAT 5, as a ground path, from the metal conduit or from the conduit to the CAT 5 shield, then the cat 5 wires (mostly in ground hits along the conduit path). The telco companies found this out the hard way; if going between two building go fiber.


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[SYQUEST]

fibervoicedata,

The RCDD you were talking to doesn't seem to know what "interference or crosstalk" is from the remark in your post.

There is no RFI, EMI, or anything else generated from fiber. It has no electromagnetic radiation that can interfere with other copper cables. But the amor shield needs to be bonded on both ends, if the cable is between two buildings. You will find that in article 800 of NEC. The CAT 5e cables will need to have protection that is bonded on both ends also, if they go between buildings aerial or underground.

....JIM....

 

[buitenhek]

??? Fill ratio applies to high voltage and deals with heat dissipation. No need in low voltage apps.???

The 569 Standard for low voltage communications cabling cable does not agree.

Also, as a sidenote: not all conduit needs firestop. Conduit stubs through firewalls are critical and require both inside & outside firestop. But I could go from MDF to IDF with contiguous EMT. And as long as both ends are in "safe" zones I do not need internal firestop. If this is incorrect, please let me know.

Regards
Peter Buitenhek
ProfitDeveloper.com

 

[BTBZ]

It will be safe to have in it onwn coduit. {fiber only}

 

[Jtodd]

To piggy back on to what mikeydidit said, fill ratio's, while effect future pulls and such, is all about the firestopping.

But as to the fiber, we stopped spec'ing inderduct and fiber and have started using armored fiber without inderduct (this is for indoor riser or horizontal runs). In either case we only use conduit when necessary, so then it doesn't mater what the cable is. So, my suggestion would be at this point, either bag the armored fiber or get some one to do the math on cable counts and fill ratios (that would be actual cable counts not estimated) and see how full those conduits are going to be. You might end up having to be the one to do the math. I usually am.



Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[oldtimerbob]

I would do as suggested, run the fiber in one and the cat5 in another.

The fill ratio can get critical as you will loose a certain percentage from the listed fill ratio charts at every 45 or 90,even with a pull box every 100 feet as suggested.
Inside the buildings you seem to be having conduit enclosed runs
If it were just outdoor or outdoor/indoor fiber then the innerduct would be bad idea too, armored is overkill for inside.

Be sure properly label each conduit at each pull box, and put the caution labels on the fiber,etc,etc,etc........(I've done a few schools before too)and that is why everything is in conduits by the way,outside of the rooms that is. We used the metal wiremold inside the rooms with a metal seperator,one side for the copper one for the fiber.

Good Luck and you will do just fine

Has been in the cabling business for about twenty years and is now the Sr PM for a cabling company located in the Los Angeles area.

http://www.globusinc.net

Also a General Class Amatuer Radio Operator.

 

[aarenot]

The district where I live pays like $25/month for a P2P T1, so I would just have them use a T1. That will take a long time to add up to the cost of the fiber alone, not including the installation, maint., etc. Is this fiber between buildings?