ECN Forum Forums General Topics of the Trade Voice - Data - Video Discussion cat 5 conduit fill

Does anybody know where I can get info on conduit fill in relation to data wires? I can find nothing on it in the Canadian electrical code. How many Cat 5 can one put in a 1 inch conduit etc....

I have pulled 8 into a 3/4" conduit once and it wasn't too hard to pull in through 2 90's...so I'm gonna guess you could pull 12...13...14?...I dunno.

I don't think that the CEC is concerned with conduit fill in this instance since you are dealing with low voltage. (non-heat-producing)


Shawn.

Conduit fill for LV and fiber cables should always be obtained from the manufacturer of the cable. Of importance here is pulling tension, nothing else. Putting too much stress on a cable while pulling it will damage it.

-Hal

take OD x OD x .7854 of each Data or Cable that well get you the Sq. inch for fill calculations. Then go to Chaper 9 table 4 Percentage fill charts .

Example 6 cad 5 at .25 dia.(what ever the Dia. is)
.25x.25x.7854=.04908
.04908x6=.2945
3/4 emt at 40 % fill (see Chaper 9 table 1)=.213 to small
1 inch at 40 % fill =.346 so I'd use 1inch EMT

Works for me.

Hbiss is on the right track.

It's not simply a matter of applying NEC tables, and other rules, to datacom wire. The NEC was never intended for such applications.

For example, typical Cat 5 specs limit your pulling force to 25 lbs ... total. It matters not how many cables are being pulled, 25 lbs is the limit.

Another insight may be obtained from phone co. specs for their lines. They'll want a 4" pipe, with a maximum of 2-90's in bends, for a single 25 pair line. (A 25 pair line is something like 5/8" OD).

Finally, I recently pulled a single 3-pair cat 3 cable through a 1/2" PVC pipe to a detached garage. While the pipe seemed plenty large, the pull was harder than I expected. It's the last time I'll make that mistake .... I think I'll START with 1" for any but the shortest cable drops.

The Nec your right is not Made for data as far as wire fill ect but its sure better then the way most do it. That is hold a bunch of wires in there hand and see how many fit in the pipe, forgetting they'll be pulling around bends and 90's. Been working for me for years pullings great. as far as Phone company a 25 pair in a 4 inch is a joke .That 4 inch at 51 percent fill would fit easly in a 1 1/4 inch . Thats just there way if we all went by fillpercentage instead of Geeee What well fit I;ll try this.

I suppose a lot depends on what the jacket is made of.
PVC is always a hard pull (like Romex)
If you had teflon it would pull easier but it costs more.

Then go to Chaper 9 table 4 Percentage fill charts...as far as Phone company a 25 pair in a 4 inch is a joke.

If you want to do another trades job you have to stop thinking like an electrician and learn how that work is done. The question of LV conduit fill comes up frequently and the replys are always along the lines of "think of a THHN size that is similar and go to chapter 9 of the NEC". I don't know how many times we have said that this is wrong. You may get your cables pulled and they may even work but most likely they are no longer in spec.

-Hal

I've NEVER EVER seen Data people with a Stress Gage on there wire pulls , Also they pull thru LB;s which does not meet most required pulling radias , Also most hire Kids to pull and install there wiring with no traning at all. As well as Proper Supports Forgets it they usually tie wrap to anything they can. Most Electricans install Data Cables far more correctly then the data people I;ve worked around and with. By the way do you use a Stress gage on yer pulls, and watch radias on pulls . :)))
Just telling it the way it is in the real world . Been
there done that

YoopersUP

By the way do you use a Stress gage on yer pulls,

I've got calibrated elbows.

Believe me, you should have no trouble estimating pulling tension once you have been doing it. It's just like estimating how much something weighs. Problem is most installers, especially electricians think they are pulling THHN and yank the hell out of it because they don't know any better. That includes untrained data installers.

-Hal

I have to pull some low voltage Belden cable (4 twisted pairs) for alarms on my generator installs. We run 1/2 pvc conduit, never more than 3 90s and it is the only thing in that pipe, but it is the hardest pulling stuff I have ever dealt with if you try to pull it dry. Just a squirt of Clearglide lube makes all the difference. Must be the jacket that makes it pull so mean without lube

Yeah, PVC pulled through PVC is the worst. Always use lube.

-Hal

Since you mention the CEC the fill for data is the same as for power or %40. for more than 2 cables per 12-1014.
The criteria for conduit fill is not mutual heating but mechanical stress upon the conductors. I presume the NEC rules are similar.

I presume the NEC rules are similar.

The NEC does not specify conduit fill for LV and communications cables.

-Hal

What does BICSI say?

The best way to install any cat5 cables into conduit is...
To leave a sharp edge on the end of the pipe, thereby when you pull them in the jacket is skinned off. Giving you approximately 25% more room. Ok that's a joke!

What does BICSI say?

Probably only one CAT5e cable in 1-1/4" conduit.

-Hal

I;ve seen data ect installed with and without conduit by so called experts , Tie wrapped to conduits, stuffed in pipes . Hight school kids hired for the summer to help. Electricans have been pulling all types of wire for years, I think there a Lot ahead of the game then you think. By the way Data, and Comm, are in the Code book youotta look um up. interesting reading.

It might be there, but no sparkies ever follow these rules and most phone/data people don't either. Inspectors really don't know what they are looking at with regard to low voltage other than fire code issues.

I had a very enjoyable experience on 1 job where I pointed out a problem with the LV conduit routing to the LV guy.
He stated flat out "This is phone wire; I don't have to follow any Codes".

The fun part came because he said this while we were both standing right in front of the AHJ, who promptly replied "Oh, yes YOU DO!"

It all got ripped out and re-done.


BTW, the VAST majority of LV installations out there look just like Yoopersup very accurately describes.

Inspectors
I am a licensed inspector in two states and we have to go several of hours in the Code in all parts to maintain our licenses. When I inspect Low voltage (50 volts & under) or line voltage (up to 600 volts) OR high voltage over 600 volts all must comply with the State & Local Codes. I think low voltage installers should be Licensed like Electricans so they WOULD be required to get the PROPER education in there trade, and attend upgrade classes . Electrican in most states are required to take Code upgrade classes .Thus they keep up with the current codes and standards. Be QUALIFIED to do your job.

That is required here in the DC area, including Maryland and Virginia. I am 100% in favor of it. Problem is, nobody enforces it, in fact the inspectors hardly even show up for the LV inspections. They might check our fire stopping while on-site for other inspections. We just pay for the permit and they are happy.

I think the idea that phone wire was exempt from the code started when these guys were working for Ma Bell and had a very strict set of accepted wiring practices. Now days the telcos hire trunk slammer "contractors" and anything goes.
Most are not licensed, in spite of a law in Florida that requires LV licenses. Phones are clearly 725 class 3 and I suppose some day the AHJs will start supervising these installations ... at least until the building slowdown is over.

I talked to my structural inspector yesterday and he said he is really slow. If it wasn't for residential remodels they wouldn't have much going at all. Even the commercial is starting to wind down.

RE: the use of 1/2" pvc. I think it is to be avoided as much as possible. From my experience, if you use a factory 90 in the run, it can be near impossible to get a fish tape thru at times. We always used a minimum of 3/4" for anything.