How big a duct for future wiring?

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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.


Re: How big a duct for future wiring?




California dude wrote:

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    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




Re: How big a duct for future wiring?


On Wed, 30 Mar 2005 19:49:35 GMT, Dale Farmer

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Howdy,

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

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."


Re: How big a duct for future wiring?


On Wed, 30 Mar 2005 18:49:24 -0500, Kenneth

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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

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Re: How big a duct for future wiring?


California dude wrote:


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Sure, check out this conduit fill capacity table:

http://www.cabling-design.com/interaction/tips/19Apr20041.shtml">http://www.cabling-design.com/interaction/tips/19Apr20041.shtml

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Re: How big a duct for future wiring?
replying to Dmitri(Cabling-Design.com, John W wrote:
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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:   click to open the full size version of the image



Re: How big a duct for future wiring?


On Wed, 30 Mar 2005 18:49:24 -0500, Kenneth

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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

Quoted text here. Click to load it



Re: How big a duct for future wiring?




California dude wrote:

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    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



Re: How big a duct for future wiring?



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air
get
crawl
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.




Re: How big a duct for future wiring?


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Why ?



--
a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.


Re: How big a duct for future wiring?


On Fri, 8 Apr 2005 05:53:13 -0700, "Watson A.Name - \\"Watt Sun, the

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





Re: How big a duct for future wiring?



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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."





Re: How big a duct for future wiring?


On Sat, 9 Apr 2005 10:54:21 -0700, "Watson A.Name - \\"Watt Sun, the


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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.


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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.

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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? )


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Re: How big a duct for future wiring?


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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



Re: How big a duct for future wiring?


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.

Mark
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Re: How big a duct for future wiring?


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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.

http://www.dishnetwork.com/downloads/pdf/technology/installation/SHOW_949_dishpro_install.pdf

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).


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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.


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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.

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



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