Can Cat5 and RG6 handle 90 degree bends?


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Old 09-20-07, 11:15 AM
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Can Cat5 and RG6 handle 90 degree bends?

OK, more on my laying conduit project:

I will be running some horizontal runs of Cat5 wire in conduit. I have some vertical drops (and rises) of Cat5 that I would like to join into the horizontal runs as the wires go off to a panel. I thought I'd run a Tee so the vertical wires can join the horizontal. However, I was concerned that the Cat5 could be damaged if I were to pull wire across the sharp 90 degree bend of the Tee. Should I be concerned with this?

I remember reading that Cat5 can be damaged if kinked or if run through a curve of small radius. That made me think the inside edge of the Tee could be hazardous.

What about using the Tee for RG6?

Thanks in advance.
 
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Old 09-20-07, 12:47 PM
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I'm assuming that you mean a conduit body Tee and not a plumbing Tee.

My coax and cat 5 for individual branches runs through 3/4 inch flexible non-metallic conduit and I used 3/4 inch conduit bodies (Tees and Ells) without problem. I have two cat 5, one cat 3 and one RG-6 to each branch. If you have more than this I would suggest that you use something bigger than 3/4 inch.

Do not try to pull cable through the conduit bodies in one pull. Pull to the conduit body and then from that point to the next access.
 
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Old 09-20-07, 01:16 PM
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Furd,

Thanks for the reply. I was actually thinking about plumbing Tees, but I had also considered using conduit bodies (though the 90 degree issue is the same.

Either way, these conduits, Tees or bodies would be behind a wall, so I'm not sure that pulling from the conduit body will be practical. In some cases, putting an access panel over body will be OK, but in other cases the access panel will kill the aestetics.

Is it generally not advised to pull a whole length of cable in one pull?
 
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Old 09-20-07, 07:27 PM
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You need to have a maximum of 360 degrees between pull points.
A conduit body would be a pull point, and needs access to pull.

You use electrical conduit and fittings, not plumbing fittings, which have too sharp a bend for wiring of any sort.
 
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Old 09-20-07, 07:56 PM
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Thanks. So if there are more than 360 degrees of bends, I need to have a conduit body that can be accessed so I can pull from there.

To help me figure out the my best option, image a scenario: Imagine that there is a horizontal run of wires in a conduit and there are NO bends in the conduit. Also imagine that there is a straight vertical wire in a conduit and that wire needs to make a 90 degree left turn so it can join up with the horizontal and continue to the end. Whats the recommended way for the wire to make that turn? Can you use a conduit body, but bury it in a wall since you don't need access to pull from it (since, in this scenario, ther are fewer than 360 degrees in turns)? Do you just leave the opening of the vertical conduit near the opening of the horizontal conduit, leaving a small gap between and have the wire go from one to the other? Something else?

I hope this is clear.
 
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Old 09-20-07, 09:33 PM
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why are you using conduit? It's going to be in walls. I mean, what's your application here, if you won't need to get back to it (conduit body in wall), or can leave and re-enter conduit?

But no, you cannot bury a junction box (ie-conduit body) in a wall, at least not by code.
 
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Old 09-20-07, 10:21 PM
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Classicsat and Integrator gave you the correct answers. If you need to make a bend inside a wall that will have no access later then use flexible conduit in that position and bend it in a wide radius.

The main reasoning behind using conduit for data cabling is that it allows for future changes. If you do not have the proper size (larger is always better) or proper access points then there is no purpose in using conduit unless you also need additional mechanical protection for the cables.
 
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Old 09-21-07, 02:37 AM
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[QUOTE=Integrator97;1232508]
why are you using conduit? It's going to be in walls. I mean, what's your application here, if you won't need to get back to it (conduit body in wall), or can leave and re-enter conduit? /QUOTE]

Originally Posted by furd View Post
The main reasoning behind using conduit for data cabling is that it allows for future changes.

I'm using conduit so to handle future upgrades.

Sorry if I seem dense or repetetive, but my real question is how a vertical run interfaces with a horizontal run.

Based on the replies, I should probably accept that it is OK for a horizontal run to not be physically connected to a horizontal run; that these short distances that a wire runs outside of a conduit is OK and won't make future pulling problematic (assuming fewer than 360 degrees in turns).
 
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Old 09-21-07, 04:35 AM
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no code that prohibits low voltage junction box's in the wall
 
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Old 09-21-07, 04:45 AM
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NEC Code does NOT apply to conduit used for low voltage cables. Place as many junction boxes or tee connections anywhere you want.

However, do not expect to replace the cable in the conduit if you install tees or put in more than 360 degrees of turns without a pull point.

My advice is to make separate runs in the wall so that you do not need tee connections.
 
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Old 09-21-07, 11:04 AM
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To change from a horizontal to a vertical run you could install a square junction & pull (J&P) box in the wall in a manner that would allow you to place a blank wall plate over it in the finished wall. This would allow you the access yet not be too obnoxious in the finished wall.
 
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Old 09-21-07, 08:32 PM
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What is your future access to the horizontal runs? Is it accessible attice, basement, crawl space, or drop ceiling between floors? If you have future access, just use conduit for the verticle drops, and run the horizontal with no conduit. This is done all the time in commercial work. The conduit just stubs out above the ceiling.
 
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Old 09-22-07, 05:22 AM
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The runs are in basment walls and ceilings. The ceilings will be sheetrock, not drop ceiling. The only access I will have will be in places where I put in access panels. There are some out-of-the-way places where I can put access panels.
 
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Old 09-26-07, 01:42 PM
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My advice, don't put any conduits in walls, only in the attic on horizontal runs (to keep critters, etc. from chewing thru wires). Just keep pull string tied off in cut-in boxes and in attic--then when you want to add any wire, pull new (with follow string) and run thru horizontals w/string also if needed. Make sure to get some cable pulling gel if your conduit gets tight, you don't want to burn thru jacket and short pairs. And forget about tees or L's, I've tied cat6 in knots and it still tests ok.
 
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Old 09-26-07, 04:19 PM
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Some CAT5 rules for running cable.
Bends are to be no less than 8 times the cable diameter, about 2 inches. 90 elbows are not suitable for pulling cat 5.
Maximum pulling force allowed 25 pounds. Anything greater affects the twists and thus the cable data carrying ability.
Maximum length 90 meters.
 
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Old 10-26-07, 06:40 PM
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Just an extra tid bit. Not going to go into the conduit, really well covered here but.. Be aware that there is also a few products, "Yellow 77" being one of them, that are cable pulling lubricants. You put that stuff in a pipe and it would amaze you what a difference there is!!

A word of caution. No normal grease or oil, petroleum based products will eat the insulation. Yellow 77 is water cleanup and doesn't turn sticky. Dish soap and water (50/50) work great _except_ that once dry, it goes really sticky. Wonderfull for the initial pull in, but almost glues it in place.

The pulling lube allows for several times the distance or turns without added pull tension and almost eliminates chaffing or burning through a sheath on a corner.

Greg Moore
 
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Old 10-26-07, 07:08 PM
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Originally Posted by Greg Moore View Post
...Be aware that there is also a few products, "Yellow 77" being one of them, that are cable pulling lubricants. You put that stuff in a pipe and it would amaze you what a difference there is!!
Greg Moore
Greg,

My cables now are now almopst all in place. The walls are still open, but will be going up in the next few days. Is this lubricant something that I should spray in now for future use, or would I spray it in later if I needed to add/replace cable?
 
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Old 10-27-07, 05:24 AM
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If the cables are already in place you don't need it.
 
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Old 12-21-07, 12:15 AM
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I realize this is an old post, but I saw a conduit body (forget the name) that is a rectangular box with holes in the two short faces; one is one end, two in the other. Thinking about the OP's original question I was thinking that a vertical run could connect to one of the two holes via a 90* sweep and the horizontals could enter the other hole. Obviously both would exit through the hole in the opposite end. Seems like there would be little or no stress on either set of wires.
 
 

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