How big a duct for future wiring?

I have a 2 story house where we are going to be putting in central air conditioning in a few weeks. I want to take advantage of this construction to put in some kind of pipe or duct that I can use to get video and Cat 5-type wiring up to the second floor

The contractor needs to run a 10" round "return" duct from the crawl space under the house up to the attic above the second floor ceiling. I want to be able to tell the contractor that I need "X" size additional clearance for this pipe. So I have some questions.

I want to install RG-6 for video applications and Cat 5 or 5+ for other applications.

Is there any engineering or technical reason why this duct can't be very close to, even touching the outside of this return duct? The return will take hot air from intakes on the ceiling or walls of second story rooms and bring it down to the furnace/air conditioner, which is located in the crawl space. (The exisitng heating ducts will bring cool air into the various parts of the house.)

How big a pipe? What kind of materials would be OK or not OK? I'm planning to have 3 "drops" in the upstairs room. Each "drop" will be a wallplate with two RG-6 and 2 Cat5 or Cat5e for networking and multiple phone line services. So that brings me up to 6 RG-6 plus 6 Cat 5 or 5e.

But I also want to be able to get satellite TV in the future. I don't have that now, and I don't know much about satellite TV right now, except that people around here seem to think it's better than cable. But, for now, assuming that I need two dishes (which I've seen on some houses in my neighborhood), how many RG-6 cables would I need? Do I also need to provide 110V AC power to these dishes?

So, to sum it up, I need 6 RG-6 plus 6 Cat 5 or 5e, plus whatever I need to for the satellite TV service. Did I leave out anything obvious?

A big thank you to everyone who shares their experience with me.

Reply to
California dude
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In regards to getting satellite TV in the future, if you are just getting DirecTV or Dish Network, you just need to run the RG6 cable from each room, then locate the ends close to where the dish would likely be located. The dishes' LNBs (low-noise block downconverter) gets its power from the receiver via the coax. DirecTV installs usually depend on the type of dish you will have, and whether or not a multi-switch would be needed. Generally if they install a 'multi-sat' dish you have a built-in 4 output multi-switch at the dish, and it can serve up to 4 satellite receivers. I've used to work tech support for DirecTV so I know all the ins & outs of those systems. Right now am just concentrating on getting my AAS degree in network systems so I can get something better. Anyway, hope that answered your question on the sat-TV portion of your post.

Reply to
Mark J

Howdy,

'Sounds like that would be enough for many dozens of cables...

All the best,

Reply to
Kenneth

Since he probably will be framing up a square around the round duct, just find out what size round conduit will fit into the corners left vacant. ( Off the top I'd guess a three or four inch round would fit nicely, but a few minutes with a piece of paper and a ruler will give you the answer. ) Put in four of them. Do remember that you want to put in fire stop barriers for this as well. This gives you a conduit for power, a conduit for data, a conduit for video, and a spare for future use.

--Dale

Reply to
Dale Farmer

As big as he can conveniently fit -- 4-6" would be my choice.

2" minimum. I'd use any PVC unless there was some local code against it. Ditto for touching the return duct. I don't think "plenum rules" should apply for residential (wood) construction -- always lots of toxic smoke. Plenum rules become important in less flammable/fireproofed situations when gasses could be carried outside the fire zone.

-- Robert

Reply to
Robert Redelmeier

Thnaks to all who responded. Isn't there some kind of guideline for installers about how many cabels of a certain type would fit into say a 2" conduit?

dude

Reply to
California dude

Sure, check out this conduit fill capacity table:

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Reply to
Dmitri(Cabling-Design.com

With our Dish installation, we have 2 dishes, with a total of 3 LNB's, connected to an external switch module. From there, a single cable feeds each receiver. Per the instruction manual, you can have up to 200' of RG6 between the LNB and the receiver, as long as you are using the newer DishPro components (as I would expect for a new installation). Older legacy systems have a 100' limitation.

If you're using a dual satellite LNB without an additional dish, depending on the LNB, you can feed up to 4 receivers directly from the LNB, beyond that you would need a switch. Check with DirectTV for specs on their systems.

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I would run a conduit from the roof (or other likely dish mounting location) to your central distribution point, this would let you locate the switch there, and feed any room via your installed cabling. keep the 200' limitation in mind when planning your cable runs.

For a dish mounting location, you need a clear line of sight to the south, as the satellites are all located over the equator.

I would install at least a pull string to the roof, as well as a ground wire (check the NEC, and your local codes). The ground wire dosen't want to be in the same conduit as the coax, and wants to run to the electrical service entrance ground via a direct route. You will probably want to ground the coax where it enters the building.

I would use only RG6 rated for 2150Mhz or higher for your installation, that way you can use any of your coax runs for satellite. Make sure to terminate them properly, using high quality connectors (I like the snap-n-seal type).

Dale summed it up fairly well.. it's always better to have more conduit space than you think you need, and it's easier to pull cable into an empty conduit, than a full one.

When installing conduit for telecommunications use, make sure that any turns are done using sweep bends, or large pull boxes to allow for minimum bend radius. If you use pull boxes, make sure they are accessable, and that you can actually pull into them. Use proper cable lubricant when pulling cable, and always leave a pull string in any unoccupied, or underfilled conduit. Use proper firestops at both the top and bottom of each conduit run.

The LNB's are powered from the receivers via the coax, but you do want to pay attention to proper grounding of the dish system.

I'd double the cat-5 to 4 drops per plate.

Reply to
Bob Vaughan

Thnaks to all who responded. Isn't there some kind of guideline for installers about how many cabels of a certain type would fit into say a 2" conduit?

dude

Reply to
California dude

The answer is, it depends. Low voltage cable or power cables? I could fit in one piece of 0000 gauge cable, or hundreds of strands of optical fiber. Rule of thumb is 3/4 fill maximum. Rule of my arm isn't strong enough is about 1/2 full unless it is a straight line conduit.

Calculate the number of square inches for the conduit cross section. pieRsquared. Find out the outside diameter of the cable and calculate the cross section of the cable in square inches. Add them up until you reach the limit. For typical cat 5 cables, this is about 26, but that is off the top of my head. Some fat low-loss coax and you would only be able to get in seven to ten of them.

--Dale

Reply to
Dale Farmer

ceiling.

One can be used for the mice to crawl thru. ;-)

Seriously, keep the RG-6 and other low level signals in their own conduit, away from the datacomm and telecomm signals.

Reply to
Watson A.Name - "Watt Sun, th

Why ?

Reply to
Al Dykes

Yo, California dude here. Don't have mice in the Golden State. Politicians scared them all off. :) :)

OK, but then how come you see bundled cables for sale at "ahem" very high prices. The ones I've seen on web sites are usually 2 Cat 5e plus 2 RG-6 or RG-6 QS. Are those vendors selling us something that is "bad for us?"

Reply to
California dude

Ahnold has really scared a lotta mice. And all the public service workers like teacher and nurses, too. They're running TV ads in prime time saying that he's "after us", meaning the workers! Finally he backed down on his pension plan, after a lotta his GOP supporters found that their constituents might not vote for them in the 2006 election! Stoopid politicians.

Anyway, the signals on the RG cables are in the millivolt and microvolt levels. They will pick up noise from the other digital cabling much easier and sooner than they will interfere with the digital signals. So it's best to run them separately, as far apart as possible.

Of course you can still get interference from digital signals leaking into other places beside the cables, such as into antennas or dishes. "Stuff happens."

Reply to
Watson A.Name - "Watt Sun, th

Yeah, You could even say, "even stoopider voters." Wot-in-heck did they expect from a guy whose pecs are bigger than his brain. Course, the Democrats haven't done too well either for the voters.

Ah. So it is NOT WISE to do long lengths of RG-6 cabel right up next to Cat5e. Thanks. That makes a lot of sense.

Alla time. Especially to guys who don't exactly know what they are dong, but won't ask. (Ever see a guy ask for driving directions, on front of his wife or girlfriend? )

Reply to
California dude

Sorry Dmitri, but the table you provided seems to contain mostly incorrect data. Please see the following re-work of your table, which includes correct data according to BICSI: [IMG]

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Reply to
John W

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