VariableARK
join:2003-03-17
USA | supporting cable in vertical conduit
We just finished a conduit run up the side of the tower and the weight on the cable is enormous at the top. What is the typical solution to this, ie. what should we be using to support the cable?
Thanks! |
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TomS_
debugger it
Premium,MVM
join:2002-07-19
Australia
4 edits | Ive often thought about this.
The best I can think of is putting some kinks in the conduit at intervals. e.g.
Use some 90 degree bends with a largish radius so as not to put too much of a bend into the cable.
Otherwise, maybe cross from one side of the tower to the other in a similar fasion to above, e.g.
Or maybe a complete 360 loop at intervals up the tower.
My theory is that there will be some friction at the bends which might help a little to support the cable. At least then the tension is broken up into a series of smaller sections. I tend to lean more towards the 360 degree loop idea.
Otherwise, each cable or bundle of cables will need its own supporting wire or rope which will have to be anchored at the top. Naturally, each time you need to add cable(s) you have to include a new support for it/them aswell.
It might not be perfect, but thats the best that Ive been able to come up with so far. Ive also not field tested any of the above, so Im not sure how well it works in practice, its just been the result of my own brainstorming for a similar situation that we may be facing at work shortly.
Otherwise, you might just have to leave breaks in the conduit every so often where you can cable tie/clamp the cables to a support. A piece of conduit cut down one side could then be clipped over the conduit sections to help form a protective cover.
Hope that helps, at least to provide some inspiration for your own ideas or improvements to the above. :-) |
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Killa200
Premium
join:2005-12-02
Spring City, TN | reply to VariableARK
what type of cable? You could see if the cable is sold with steel messenger cable in the jacket and then tie off the messenger at the top to hold the weight of the cable. |
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viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA
| reply to VariableARK
What I Have seen and used on the past in buildings ( never had the chance to do it on a water tank) was every floor had a junction box on it that had conduit going from the bottom floor up to the top floor and conduit out for each floor.
I cant remember the name of the unit we used but the attached to the inside of the conduit and snapped in, then after you pull your cable thru you would attach the cable into this hanger I will call it. You can then zip tie or bread tie hahaah to the hanger so every 15-20 feet your cable was supported.
You could possibly do the same for an outdoor install just put a junction box every 15-20 feet and attach something in there to tie the cable to for strain relief??
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John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp | reply to VariableARK
First, what kind of cable?
And how high to the top?
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A is A |
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shorthairedp
join:2005-11-21
united state | if your certain this is the last cable youll but in, fill it with epoxy, a lot of epoxy |
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battleop
join:2005-09-28
00000
| reply to VariableARK
I looked at putting an array on top of a 110 billboard. It was a monopole design and there was no real way to put a conduit in the pole. The idea I came up with was to get a steel cable to run top to bottom and wire tie the cables to that cable. The project fell through so I never had a chance to try it. |
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petecarlson
join:2004-11-06
Baltimore, MD
| reply to VariableARK
Pull box every 50 - 100 feet with cable hangers. I use a self tapping screw wet installed with 5200. They look like finger trap things. The thing is that you need to pull through them on the way up. Mount them ahead of time and zip tie them in a compressed position so you can pull through them. Once the cable is in place, pull the cable up a little bit and cut the zip tie. |
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nunya
SEE ROCK CITY 475 MILES
Premium,MVM
join:2000-12-23
O Fallon, MO
clubs:
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1 edit | reply to VariableARK
First and foremost, don't add offsets, bends, or other radii to the run of pipe.
SOP is to place junction boxes with insulating wedges every hundred feet or so?
How long is your run? What type of cable (and how many)? What type of conduit. What size of conduit?
If your run is less than 100' and you are using cat 5/6 cable, I'd put a large pull box at the top and support the wire with a grip (Chinese finger).
Or, just put a simple 90 at the top. After the 90, use a conduit seal body to seal the pipe and hold the wire up.
Adding bends is a bad idea. When you need to pull new wire up, it would be a PITA. Code only allows 360 degrees of bend on any run of pipe. I can tell you that pulling anything through 360 degrees is a PITA.
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Looks like Reverend Wright got his wish - God Damn America. |
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AMD Phreak
Premium
join:2003-12-14
| reply to VariableARK
I think nunyas idea of jboxes and hoist grips would be best. you can find hoist grips at any store like tessco, talley, hutton, etc. Figure out how big your cable bundle is and then order the hoist grip for that bundle size.
Strap it down in the jboxes as you go up the structure. |
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VariableARK
join:2003-03-17
USA
| reply to VariableARK
Sorry it took so long to reply.
It was a 120ft run, so what I did was take two pieces of flat steel and sandwhich them over the cable so that they can't slide down any (unless my flatsteel grip fails).
The chinese fingers are those the "hoist grips" you talk of AMD Phreak? I will have to look those up for future projects.
Thanks for the ideas! |
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AMD Phreak
Premium
join:2003-12-14
| said by VariableARK  :The chinese fingers are those the "hoist grips" you talk of AMD Phreak? I will have to look those up for future projects. Yeah, that's the technical name of the product. If you call up a distributor and ask for them they'll know.
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