D
dusty
Guest
How close to power lines in the attic can network cable be without causing interference.
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W
whit3rd
Guest
On Sunday, June 14, 2015 at 5:39:41 PM UTC-7, dusty wrote:
> How close to power lines in the attic can network cable be without causing interference.
Fire safety usually dictates circa 1 foot separation (that's because of lightning,
not for normal operation). They work fine if you bundle AC and data wiring all
together with a velcro strap under your desk, of course, but wires in the
attic might be regarded as 'installed' in the building, and that's the recommended
separation of low-voltage and power wiring runs, if there's no conduit.
> How close to power lines in the attic can network cable be without causing interference.
Fire safety usually dictates circa 1 foot separation (that's because of lightning,
not for normal operation). They work fine if you bundle AC and data wiring all
together with a velcro strap under your desk, of course, but wires in the
attic might be regarded as 'installed' in the building, and that's the recommended
separation of low-voltage and power wiring runs, if there's no conduit.
M
M Philbrook
Guest
In article <B7qdnV4VKItXg-PInZ2dnUU7-XmdnZ2d@giganews.com>, "dusty "
says...
You need to worry more about lightning strikes..
Keep the wire far enough away so that if your power likes
do get hit, the strike can not make it over to your network
cables.
That's not to say that your devices connected to the grid
won't get hit so what ever
At least 6 inches or more I would say for that, as for basic
line noise, you can get close to the wores.
Network cables are twisted pairs so they are design to reduce
external noise to a degree.
Jamie
says...
You need to worry more about lightning strikes..
Keep the wire far enough away so that if your power likes
do get hit, the strike can not make it over to your network
cables.
That's not to say that your devices connected to the grid
won't get hit so what ever
At least 6 inches or more I would say for that, as for basic
line noise, you can get close to the wores.
Network cables are twisted pairs so they are design to reduce
external noise to a degree.
Jamie
J
Jeff Liebermann
Guest
On Sun, 14 Jun 2015 19:39:36 -0500, "dusty " <dustyŽ.net> wrote:
>How close to power lines in the attic can network cable be without causing interference.
I vaguely recall that NEC requires 2" separation between signal and
power cables for safety. I'm not sure of the 2" and am too lazy to
look it up.
If you're worried about coupling between the 60Hz power lines and the
CAT5e network cable, everything depends on the distance that they run
in parallel. If it's fairly short, or the cables simply cross,
there's no cross coupling. However, if you're running something like
50ft next to each other, expect problems.
In theory, ethernet is immune to low frequency (60 Hz) interference.
In reality, the power lines contain substantial amounts of higher
frequency noise and junk that MIGHT couple to the ethernet cable. The
common mode rejection of the twisted ethernet wires dramatically
reduces coupling, but if sufficiently strong, you may have problems.
For example, if you're wiring a factory full of sewing machine motors,
you should certainly keep the network cables away from the power lines
as the variable frequencies, high power levels, and high noise levels
from these motors can cause problems.
You really should ask this question in one of the wiring newsgroups,
such as comp.dcom.cabling.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
>How close to power lines in the attic can network cable be without causing interference.
I vaguely recall that NEC requires 2" separation between signal and
power cables for safety. I'm not sure of the 2" and am too lazy to
look it up.
If you're worried about coupling between the 60Hz power lines and the
CAT5e network cable, everything depends on the distance that they run
in parallel. If it's fairly short, or the cables simply cross,
there's no cross coupling. However, if you're running something like
50ft next to each other, expect problems.
In theory, ethernet is immune to low frequency (60 Hz) interference.
In reality, the power lines contain substantial amounts of higher
frequency noise and junk that MIGHT couple to the ethernet cable. The
common mode rejection of the twisted ethernet wires dramatically
reduces coupling, but if sufficiently strong, you may have problems.
For example, if you're wiring a factory full of sewing machine motors,
you should certainly keep the network cables away from the power lines
as the variable frequencies, high power levels, and high noise levels
from these motors can cause problems.
You really should ask this question in one of the wiring newsgroups,
such as comp.dcom.cabling.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558