Wiring ethernet inside ductwork...


Old 02-06-06, 08:16 AM
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Wiring ethernet inside ductwork...

I believe for my home, this is going to be the easiest way to go. I am planning on upgrading my home to support a Cat6 network -- I have a rack mounted in my basement with my server, and eventually a Cat6 patch panel and GigE switch. I will probably move my cable modem down there as well.

Anyhow... my question pertains to doing the actual wiring. How exactly would you make use of a heating duct to run wires? I mean, I can probably guide it down to the furnace room (where my rack is mounted) but how would I 'exit' the cable from the duct? Is there something else I should be doing, or am I overlooking something?

Any tips, tools, etc that I might need would be greatly appreciated. I haven't started doing any shopping yet (not even for cable) as I'm waiting on my tax return, but I figure this is a $500 project between the network equipment, cables, and the like.

Thanks for any help you can give... I don't want to make any 'booboo's either Oh, and I know.. I am buying plenum rated cable.
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Old 02-06-06, 08:44 AM
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Technically speaking, there are no codes regulating low voltage communication cable installation. If you want to abide by line voltage rules, cables are not allowed in heating or air return ducts. Plenum rated cable is for use above the drop ceilings in commercial buildings which is equivalent to the cold-air returns in a residential home. The cable is not rated for use in the heat side of the air handling system.

If it was my house, I would avoid running any cabling in the ducts if at all possible. Often the trick is to find a chase from the basement to the attic through which you can run cables up to the attic then drop into the second story walls. For the first floor, just run the cables up into the walls from the basement. If you have a finished ceiling in the basement or some other big complication, I would consider wireless ethernet.
Old 02-06-06, 08:54 AM
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Wireless isn't an option... I have it already but with a lot of interference... and I have a good router too.

Ah well, I will be in my attic today then trying to find a way to get all the way downstairs

The second floor will prove to be quite difficult I think though.
Old 02-06-06, 03:19 PM
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Look around the plumbing stack. That is often a way to the basement.
Old 02-06-06, 04:52 PM
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Article 830 applies to Cat 6 cable, as it is network powered broadband communications system cabling.
Section 830.55(B) permits cables installed in ducts, plenums, and other spaces used for environmental air. The cable type must be Type BLX.
This is a specialty cable, which I don't think is carried by any retailers.
Old 02-06-06, 11:48 PM
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you still have the problem of exiting the ducting on both sides. if the rooms are carpeted and have baseboards, you may be able to lift the register and a section of baseboard, and snake the cable under the carpet, and into the wall from behind the baseboard.

Make a hole in the wall behind the baseboard ajacent to the register. Make sure you are between and not too close to any wall studs, and that the hole will be covered completely when you reinstall the baseboard.

Above the baseboard hole, cut out a square hole for a low-voltage remodel box. This type of box usually has no back. The top of the hole should not be higher than 16" from the floor, but high enough to clear the baseboard. (where is a matter of asethics.)

Fish the cable from the vent, under the carpet, thru the baseboard hole, up the wall and thru the box. Install a jack and place cover to finish the outlet, re-tack the carpet, and reinstall the register. Replace the baseboard.

best wishes.
Old 02-08-06, 09:23 AM
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This is one of my specialties. I have faced this situation many times. First off, CAT6 is a bit extreme for residential use, however, it never hurts to install the highest grade telecommunications cabling. I too have run all CAT6 in my house, however I do not have a need for it. You can push a gig on CAT5E actually, especially at those lengths. Just make sure you have a gig capable NIC on every pc and server. Your broadband will not support that data rate though unless you have one of those smarthomes with a fiber link. Then I will just be mad. Also, obviously make sure that router is able to handle the gig.

anyhow, if you have access to an attic for second floor and a basement or crawl space for first utilize those routes over air ducts. Cable can get damaged in ducts and regular plenum may still become brittle and deteriorate after awhile. I typically find a gap in the Air Stack for plumbing or DWV and fish that with a pull string and weight to get to a second floor. Otherwise conduit on the outside (grounded) is the way to go. You also may consider a flexible pvc or smurf tube for running in ductwork poke a hole on an adjacent wall either inside vent to go thru wall or in route of the duct. Especially good locations suitable for plenum is cold air returns. You can utilize those good because they typically are using empty space with no real duct work. If its all on the first floor and you have access from below drill up and cut in a hole with a mud ring or single gang retainer.

If I were you I would provide a wire for Phone and Coax even if you are running VOIP Or if you want run two CAT6 cables to each location in home and provide them to your rack and add a phone connection splitter. Your phone typically will only require CAT3 rating. Very inexpensive wire.


18 Volt Cordless Drill with a nice sharp paddle bit
Punch Tool for terminating jacks
Crimper for terminating to RJ45 Modular plugs
Simple wire map tester to make sure all your pairs or terminated correctly
Snips or cuts for stripping cable and cutting
Tie Straps and or cable tie downs for routing cable ( dont over tighten )

For a complete CAT6 GIGABIT Capable installation

500' CAT 6 Cable should be good for a home
CAT 6 Jacks
CAT 6 RJ45 Ends and/or Patch Panel Rated for CAT6
Faceplates Leviton or Ortronics are good for residential
Mud Rings or Retaining Clips

Any questions, feel free to message me.
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