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power and computer line in same chase bad idea???

Posted by jaansu (My Page) on
Tue, Nov 30, 10 at 12:21

My reading of this forum suggests that power and data lines in close proximity are a bad idea, particularly if parallel, for efficient connection to a router. Unfortunately, the best way I can get a cable from my router to my 2nd story office is to use a difficult path I used last year to pull two 12ga lines from the basement to the attic (crazy path, drilling at sharp angles from interior walls on one floor to a closet on the next and so forth). I would use one of the existing cables to pull the line through the same path. So the cable would eventually be right next to and intertwined with these power lines. For a variety of reasons, wireless is not a good option. So, are my odds good for happy computing or should I give up on this idea and look for something else?


Follow-Up Postings:

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RE: power and computer line in same chase bad idea???

Alongside of power cables should not be a problem for UTP networking (GigE, etc...). You just don't want them to pass inside junction boxes where connections are made to the power line stuff.


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shielded UTP cable

No, no junction boxes or any connections, just cable. While I'm at it, would UTP cable come in shielded forms that might be better? Or just overkill?


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RE: power and computer line in same chase bad idea???

would UTP cable come in shielded forms that might be better?

UTP means "unshielded twisted pair," so I don't think you'll find too much shielded unshielded cable offered for sale. :)

However, Cat5/5e/6 and similar network cabling is indeed available shielded. If the cables are going to be in proximity for more than several feet, that'd be my preference.

It's possible that plain old UTP may cause you no problems, but if it does ... let's just say that I'd rather fish only once.

If you can't go with shielded network cable, I recommend loosely twisting the power cables - one twist per foot or so. That serves a function complimentary to the twists in the twisted-pair network cable - that is, helping to reduce radiation from the power cable.

FWIW, 3-conductor plus ground NM comes from the factory with a nice twist in it.


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RE: power and computer line in same chase bad idea???

I wouldn't recommend it. When we're running alarm cable, we locate a wall in the attic that we can get access to to the bottom, in, say a furnace room. We verify using a 'mouse bit' aka aviation bit, a thin one - drilling through the base board at an angle so you go through the bottom of the wall plate (you really want to know pretty much exactly where it is by measurement before you do it) - drill up into bottom of wall, drill from top of wall in attic downwards, drop fine chain (not the ball stuff, too weak) into the wall, hook with a coathanger (stick a magnet to it if you can) and pull your wire through.

Under most codes low voltage and high voltage can't share a hole. In practice, shielded would probably be fine, but I believe the reason for the prohibition is in case a nail goes through both wires, the low voltage cable can be energised with mains voltage (plus the risk of hum etc.)

I would ALWAYS choose wired over wireless.


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RE: power and computer line in same chase bad idea???

If it is shielded it isn't cat 5. Cat 6 and 7 come shielded. I'd but the best in you can afford now if you're trying to stave off obsolescence, or just leave access to the chase or install some conduit/smurf tube if you can't predict the future better than me.

What code are you talking about "low and high voltage" can't share a hole. Never heard of such a thing.

I've worked with network and power wiring for a long time (25 years) and I've never had a problem with a rated data use of cat5/6 coexisting with power cables. It's what it's designed for. Start screwing around with things it's not designed for like trying to shield cat 5 and yeah, you run into trouble.


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RE: power and computer line in same chase bad idea???

I have cat 5 with a mylar shield and a drain wire. Solid stranded too. It's Belden.

The not sharing the hole thing is code in Canada, or at the very least, it's a practice frowned upon. I don't have the code book in front of me right now.


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RE: power and computer line in same chase bad idea???

Mylar is not a shield...it's just insulation.As I stated, the cat 5 spec mandates NO shielding. If there's shielding, it's not cat 5.


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RE: power and computer line in same chase bad idea???

"the cat 5 spec mandates NO shielding"

While the spec may not require shielding, it is not going to prohibit it.

The spec is the minimum for the class, not a prohibition on being better.

While Mylar itself is not a shield, Mylar with a metallic layer (aluminum is common) IS a shield. When used as a layer with a less than 100% optical coverage braid you can get very good shielding form the combination.

Any LAN system that cannot operate with a LOT of 60 Hz interference is NOT going to work worth a darn.
It is everywhere, as both electric and magnetic fields (50 Hz in places that use that power frequency).


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