Re: shielding low voltage wire, running low voltage wires aside 12-2 romex

[Frank Olson <use_the_email_links@xxxxxxxxxxxxxxxxxxxxxx>]

John M Lauck wrote:
> On Jan 29, 10:32 am, Frank Olson
> <use_the_email_li...@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>> Robert L Bass wrote:
>>> "John M Lauck" wrote:
>>>> Couple questions:
>>>> First, is it possible to run Swann security camera (black, shielded,
>>>> power/audio/video in one) wire along side 12-2 romex.  I'm wiring
>>>> security cameras and external motion lights and it would be much
>>>> easier to run this pair of wires side by side.  Is there any problem
>>>> doing so?
>>> Don't do it.  Code requires separation for safety.  For optimal
>>> performance stay 12" minimum from 110VACD and 24" from 220VAC.  Cross at
>>> right angles where necessary.  That said, it's ok to run close and
>>> parallel for a few feet, say up a wall to a light switch.  But farther
>>> than that keep your distance.
>> BAss, you're a moron.  So you have to maintain separation for safety
>> (according to Code)...  yet it's "OK to run close and parallel for a few
>> feet" (which is *against* Code)...  Your mental faculties must be on
>> hiatus.  This has got to be one of the dumbest things I've seen you
>> post.  "Don't do it, but it's OK if you do"...  Right, Bass.
>>
>> NEC requires a minimum 2" separation between high voltage (110VAC) and
>> low voltage (communication grade) cabling.  If you're running
>> communication grade wire down a wall which also happens to have a light
>> switch, it's going to be darn difficult to maintain that separation
>> unless you cut out the dry wall and physically staple the wire.  Most
>> alarm installers (primates to BAss) recognize this and will use separate
>> wall entry points from any AC wiring that's terminated or run in the
>> same wall cavity.  Electrical inspectors will look for this.  They don't
>> bring the X-Ray equipment out to ensure any wiring you've run inside the
>> wall complies with NEC.
>>
>>
>>
>>>> Second, I've read plenty of info that specifies if you have to cross
>>>> Cat-5 wires with electric wire you cross the two wire
>>>> perpendicularly.  However, in an older home where there's only a small
>>>> chase to get wires to their destination there's bound to be a place
>>>> where the wires are side by side.  Can you wrap the low voltage wires
>>>> with foil or something to shield them?  Is this necessary for short
>>>> points of contact?  Is this the same for speaker/security or coax wire?
>>> For short distances necessary to get to a service point from the main
>>> run, it's ok to stay under 12" away.  Don't run the two types abutting
>>> each other though.
>> He shouldn't have a problem using shielded wire.  The "rule" (code to
>> you) is to maintain a 2" separation.
>
> Thanks for the tips.  I've been trying to maintain separation in all
> cases but as several mentioned, it's nearly impossible in an older
> (late 1800's) home to do this in all cases.  12" of separation sounds
> ridiculous especially when studs are often 16" or less on center.  You
> can only drill so many holes before you are doing more structural
> damage than necessary.  I thought about testing it by wrapping some
> low voltage wire around some hot romex and testing throughput on the
> low voltage.  Has this been done and published before?

"Testing?"  *Experience* demonstrates that you should maintain a larger
separation than the 2" required by NEC.  When we do custom pre-wires, we
*always* go in *after* the electrician has completed his.  This ensures
that we can maintain maximum separation (and minimize potential problems
with interference).  When you're renovating an existing house, it's a
little more difficult but experience and "common sense" will ensure you
"win" in the end.  If you lack the experience part, asking in a forum
like this will help.  There are a large number of experienced home
automation specialists here.  Bruce R., Bill Kearney, Dave Houston to
name a few (although Bill and I don't quite see "eye to eye" regarding
Bass and frequently butt heads).  :-)

You're using shielded wire (or at least that's what you've indicated).
  You shouldn't have a problem.

Good luck!!!