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How many pieces of Cat6 can you fit through a pipe with a 5” inside...

Deskey (TechnicalUser) (OP)
3 Jan 03 9:56
How many pieces of Cat6 can you fit through a pipe with a 5” inside diameter?
Bobg1 (TechnicalUser)
3 Jan 03 10:38
Quite a few. Some other variables you need to consider are
total length and how many turns. These will make the pull more difficult if you are near capacity with cables.
Deskey (TechnicalUser) (OP)
3 Jan 03 10:54
I agree, those variable are important to factor in.  Is there a formula though to actually calculate a good number on how many Cat6 cables you can fit in a 5inch inside diameter pipe?  A Cat6 cable is roughly about 1/4 of an inch thick and if the inside diameter of the pipe is 5 inches, than you would think 20 Cat6 cables would fit (5 x 4).  But that's just vertical though, how would you figure out how much would actually fit in the the whole circumference of the 5inch pipe?
smah (MIS)
3 Jan 03 12:02
Bobg1 (TechnicalUser)
3 Jan 03 15:17
Ok, calculating using #6 thhn which is also approx 1/4 in dia. using 40% fill you can get 160 in a 5 in.
daronwilson (Vendor)
3 Jan 03 16:38
Very good ideas!  You will find quite a difference is the answer depending on what reference you look in.  Also depending on the application, you will find quite a variance.  

NEC - in the 2002 NEC 800.48 "Where communications wires and cables are installed in raceway, the raceway shall be either of a type permitted in Chapter 3 and installed in acordance with Chapter 3, or a nonmetallic raceway complying with...   Exception:  Conduit fill restrictions shall not apply."  Go figure, I spend years trying to convince my electricians to oversize the pipe and not loop so many together, and then the NEC changes to give them leverage.  Fortunately they don't pay much attention to this section.

EIA/TIA - as you might be aware, the EIA/TIA standards (specifically 569) see this a bit different.  The EIA/TIA standards are much more conservative and reflect closely prior versions of the NEC.  I don't see in the standards a reference for 5" pipe, so I would guess you are back to measuring the inside diameter, calculating the area, and going for 40 per cent of that to be conservative.  Also keep in mind that Cat6 is 23 gage wire, so the overall jacket may be slightly larger.

Installation - is this a 24" piece of pipe through the floor or a 100' long piece with 2 90's in it?  If you are in the design stage of the game, be very carefull with this portion.  While you might design a solution meeting the specifications, you may not be able to get that many cables pulled in there without exceeding the pulling limit on Category 6 wire.  

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

Bobg1 (TechnicalUser)
6 Jan 03 7:49
Exception:  Conduit fill restrictions shall not apply.

That figures, Guess thats what I get for not reading the latest. Oh well at 40% thats still a pretty darned big bundle to try to drag through any kind of a run.
Now whats the formula for calculating the drag of a bundle that size, to see how far it can be pulled and stay within the pulling limit?
daronwilson (Vendor)
6 Jan 03 12:35
I don't know of a formula for that one.  Again, if it is a 36" hub into a telco closet or between floors I would be inclined to think I could carefully load that up to 80% or so without damage.  If it is a 100' long run with 2 90 degree corners in it, totally different story.

In the past, I have installed (while being told what to do) wire, pulled so hard that wire actually suck back inside the jacket 6-8 inches.  My guess is that was about 80-100 pounds of pull.  Actually terminated, scanned and tested it to 5e standards no problem.  I certainly wouldnt recommend it, nor do I allow it on my installations, but that wire can take quite a pull.  Of course, if it doesn't test out, you have to pull the whole mess out and do it over, so generally it just isnt worth the risk.  As we ask more and more from our copper cable, we will have to be more carefull in installing it so that it will pass higher standards.

I find it best to pull those larger bundles as one pull, distributing the load/weight over the entire bundle if possible.  If it is pulled in one or two at a time, I would definately soap the heck out of it and stay at a lower fill percentage.  Each wire going in drags across other wires and can often burn and damage the existing wire.  We try to pull to the telco room and leave slack, then pull the entire bundle in through the 4" feed conduits where possible to avoid the chance of burning the existing wires.

Again the answer depends on the specific installation and application, and whether you are designing this to be a standards compliant installation (i.e. spec another conduit so you can keep the fill ratio compliant) or if you are installing in an already built structure and you need to determine how many you can safely put in existing raceways.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

Bobg1 (TechnicalUser)
6 Jan 03 15:49
Deskey
Depending on the length of the run and where it is located,
can you do what you need with a cable tray?
InnoTech (ISP)
6 Jan 03 20:46
I think Bodg1 means the length of the "pipe".

my thoery is "depends on who's looking and whos going to look." because just like daron said, without putting the cable through too much strain there should be no problems...... as long as they test out good!! :)

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