ethernet and AC in conduit

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I know it's not recommended or allowed by the NEC , but I'm wondering
if anybody knows how likely I am to have problems if I run ethernet
and AC (120 volt) in the same conduit for  20 meters....

thanks,
Steve

Re: ethernet and AC in same conduit
added the cabling & ethernet groups -

seaweedsl wrote:
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Re: ethernet and AC in same conduit

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None at all if you run the Ethernet over fiber.

If not, don't whine if your fire insurance is void...


--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Re: ethernet and AC in same conduit
ps56k wrote:
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hmmm - we ran the AC in the required conduit and metal boxes
to totally contain the AC/fire gremlins.

The "low voltage" stuff in the drop/plenum ceiling was a little trickier...
Either - it was the more expensive "plenum" cable, hung from the I-beams,
or run inside a pipe/conduit just for physical protection
and it would exit from the conduit at a patch panel on either end.

Same with the low voltage telco/phone wiring.... which you didn't mention.



Re: ethernet and AC in same conduit
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What would a "problem" be for you?

In theory, ethernet and 60 Hz AC won't interfere with each
other, so separation and isolation are irrelevant.  Now, if
that AC is going to some noisy electrics (arc welders) or to
some sensitive equipment, there might be some interference.

But you are taking an unapproved risk and depriving others
of a layer of protection.  Break the insulation, either by
a pulling scar or mechanical accident, and they are _much_
closer to a fatality.  Do you want other people setting
traps for you?  Don't set them for them!


-- Robert


Re: ethernet and AC in same conduit
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As far as I know, it will likely work fine.  

As you say, not allowed by the NEC.  Some time ago, I predicted
that you could run ethernet with 240VAC common mode on the cable,
but I never got around to trying it.  (Also not allowed by the NEC.)  

Use cable ties onto the outside of the conduit.

-- glen

Re: ethernet and AC in same conduit
glen herrmannsfeldt wrote:
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This would be an American thing?

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Don't think the UK equiv have the same level of paranoia.

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Gruesome, and tricky if the conduit is underground !

Re: ethernet and AC in same conduit
Mark McIntyre wrote:
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Yes, it is an American thing.

NEC = National Electrical Code.

The NEC is produced by the National Fire Protection Association and
essentially codifies nationally accepted practices for electrical
installations.

While there isn't a single USA wide National code, the states and
municipalities that are responsible for inspecting and approving
electrical work almost always specify that the work must meet applicable
NEC standards.

John
--
John P. Dearing
A+, Network+, Server+
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Re: ethernet and AC in same conduit
On Sat, 03 Jan 2009 14:19:44 +0000, Mark McIntyre

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they did last time i had a copy of the IEE regs (a few versions back).

Best practice was to separate mains and low voltage cabling, which is
1 reason you get separation in floor boxes & multi compartment
trunking.

the issue here is that Cat5 etc is general purpose low voltage signal
cable, and conductors are exposed on RJ connectors so they are easy to
touch during changes.

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you can get shielded Cat5 - given using it in other environments like
chemical plants you should be able to find an equivalent with higher
rated insulation, steel wire armour or whatever if you have to do
this.....
--
Regards

stephen_hope@xyzworld.com - replace xyz with ntl

Re: ethernet and AC in same conduit
Stephen wrote:
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Code of Practice, not law or regulation.

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Sure, but BP isn't the same as regulatory requirement. As much as
anything else you don't want some moron electrician cutting the network,
  or an equally dim network tech frying himself on the mains. In the
same way b-p mandates that the upstairs ring runs upstairs and the
downstairs one runs downstairs, thus neatly avoiding what I did a few
years back - pulling the upstairs ring's fuse and cutting the cable,
only to discover my predecessor had run the downstairs loom upstairs. I
discovered this, of course, by cutting through the live ring... :-)


That said I can't be a*sed to find my handbooks right now but I don't
belive its compulsory to separate them.

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Sure, but still tricky to tie onto the /outside/ of underground conduit.
There tends to be earth in the way... :-)

Re: ethernet and AC in same conduit
On Sat, 3 Jan 2009 08:15:31 +0000 (UTC), glen herrmannsfeldt

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"Use cable ties onto the outside of the conduit."

Also not allowed ny the NEC either if you want to be pedantic.

If you can find cat 45 cable with a jacket rated at >120v it is
perfectly legal to run it in conduit with line conductors. I have even
heard compelling arguments that the romex insulation/jacket is
sufficient "separation"

Re: ethernet and AC in same conduit

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I did (in the lab); it worked fine.


--
Rich Seifert              Networks and Communications Consulting
                          21885 Bear Creek Way
(408) 395-5700            Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com

Re: ethernet and AC in same conduit
On Sat, 03 Jan 2009 10:13:34 -0800, Rich Seifert

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The ultimate PoE?

It's not the 60Hz, it's the noise, spikes, and glitches on the line
that cause problems.  

I inherited a customer that had CAT5 running parallel with about 100ft
of Romex.  That's what happens when you get an electrician to run the
residential network wires.  They were getting erratic errors on this
ethernet connection and were wondering why.  I tested it (using SNMP
to collect errors and stats) and didn't find anything unusual.
However, I did it on a weekend, when nobody was around.  During
business hours, there was some heavy machinery running on the same AC
circuit that was producing large power line glitches, spikes, noise,
etc, which were being induced onto the CAT5.  Although there was
probably no 60Hz coupling, and the common mode rejection should have
prevented the glitches from being a problem.  That wasn't the case as
the distances between the various AC conductors and the CAT3 were
different, therefore, different induced voltages.

Incidentally, they also had POTS phone service shared on this run of
CAT5.  There was 60Hz hum, but only on some instruments.

I'm wondering about the safety issues.  Run enough AC and ethernet
wires in parallel, and eventually, it becomes a transformer.  I'm not
sure how much voltage it would induce in unterminated CAT5 wires, but
I wouldn't want to find out the hard way.  It should be easy enough to
test the worst case.  Take a length of CAT5 and apply 117VAC to one
pair.  Measure what appears on the other pairs.  Try different
lengths.

--
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

Re: ethernet and AC in same conduit
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It is required to run the hot and neutral wires through
the same metal conduit for a good reason.  If you do, then
the net current through the wires should be zero.  If not,
it will try to induce current into the conduit, or into
other wires in the conduit.

-- glen

Re: ethernet and AC in conduit

:I know it's not recommended or allowed by the NEC , but I'm wondering
: if anybody knows how likely I am to have problems if I run ethernet
: and AC (120 volt) in the same conduit for  20 meters....
:

Unlikely to have technical problems BUT should there be a fire/injury and
the insurance company finds out they will void your coverage.




Re: ethernet and AC in conduit
NotMe wrote:
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I have 240v and 100-base-T running alongside each other in several
locations in the house. No issues.
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I very much doubt that's true, unless they have an exclusion in their
policy documentation. On what grounds would they do it?

Re: ethernet and AC in conduit
Mark McIntyre wrote:
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I know of a case where someone added additional wiring to their home and
it burned down because a wall fixture they had added had a much larger
than rated wattage bulb installed and was left on continuously and
ignited the wall. It was a newer home and apparently there was language
regarding code compliance. They tried to hang the inspection company but
the application and inspector's notes showed a lower outlet count than
what was installed.

Re: ethernet and AC in conduit
Very good.  This extended dialogue about insurance and such is
probably useful for others....

[Philosophy/Rant warning]:  but personally, I have never had to live
or work in an insured environment, thank God.  My father is an
insurance agent, but I consider most insurance (including health)  to
be a cure worse than the disease, both on a society-wide basis and
personally, unless you are one of those ugly people who game the
system at the expense of others.

Anyway, I am able to deal with reality and not worry about insurance
and litigious society.   My own home in the US is an old adobe with a
metal roof  (all new wiring installed illegally by me) so they never
would insure it anyway, even if I wanted. I'm self-insured and like it
that way.  I try to do things practically correct more than literally.

As far as safety, living in a developing country (Mexico)  one sees
both how useful (at times) and how ridiculously anal (other times) the
hyper-safe US mentality can be.  I'm not advocating it, but here,
people wire things up with open connections, no tape, no wire nuts, no
boxes, and it still works !  OK, they do usually have boxes and tape
on connections , but sometimes not- and bare wires are common
enough.    For whatever reason, death or injury by shock does not
appear to be at a detectable level compared to, say, crime or car
wrecks etc.    I've never heard of an electrical injury in this area,
but vehicle accidents are announced daily .  I suspect that living in
a self-responsible society helps people develop awareness of hazards,
although rank stupidity is hardly in short supply here either !
__________________________________

In my case, I am considering running an ac extension in a conduit with
the Cat5e  for powering an AP on a pole.  Too far to extend the DC
side of the wall wart.    Nobody will ever be anywhere near this
plastic conduit and the likeliness of having both the hot and ethernet
insulations fail in the exact same point and touch and then have
another failure at the connector end such that anybody would touch
that is very, very high.  More likely to get snake bit standing
there !

Though now that I've decided to deploy an old Linksys V4 in this spot,
I'm seeing that for $20 I can get a power injector/splitter kit.  I
wonder if the 12 v power supply will handle 120 feet.  I remember Jeff
pointing out that they are quite robust and can take a huge drop in
voltage...

Let's see, I send 12v * 1A over 120' of 23  ga wire?   5 volts, it
appears.   But doesn't  POE use a pair for each side, so two 23 ga is
what, like 18 ga?   If so, then 1.5 volts... the linksys could handle
it ?

Steve





Re: Ethernet and AC in conduit for remote WAP
yeah - we have warning labels on everything,
and lawyers just waiting at the gate....

My son & I find it humerous to read some of the warning labels
on just every day things - look at ALL the labels pasted on a plain
extension cord :)

seaweedsl wrote:
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Re: Ethernet and AC in conduit for remote WAP
ps56k wrote:
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ps56k:

You're not the only one to get a chuckle out of Warning Lables.

http://www.physics.uwo.ca/~harwood/humor14.html

John

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