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Ethernet and Power Cables

R

Rene

Jan 1, 1970
0
I was told that it is not a good idea to run a power (120 AC) cable together
with an Ethernet cable because the AC cable would disrupt the transmission
on the Ethernet cable.



Is this true? If tit is, is there a way to have the power cord shielded so
that it does not bother the Ethernet cable or vise versa? Can I buy cables
that already include a shield on them?



Thank you.
 
P

peterken

Jan 1, 1970
0
There's another very good reason for not putting data together with mains,
it's called safety..... :-S
Minimal distance is 30cm if no wiring tubes are used over the individual
lines.

And indeed, voltage spikes on mains *might* momentarily disrupt data
traffic, or even damage databuffers due to induced spikes




I was told that it is not a good idea to run a power (120 AC) cable together
with an Ethernet cable because the AC cable would disrupt the transmission
on the Ethernet cable.



Is this true? If tit is, is there a way to have the power cord shielded so
that it does not bother the Ethernet cable or vise versa? Can I buy cables
that already include a shield on them?



Thank you.
 
C

Clarence

Jan 1, 1970
0
Rene said:
I was told that it is not a good idea to run a power (120 AC) cable together
with an Ethernet cable because the AC cable would disrupt the transmission
on the Ethernet cable.

Is this true? If tit is, is there a way to have the power cord shielded so
that it does not bother the Ethernet cable or vise versa? Can I buy cables
that already include a shield on them?

Thank you.
Electrical code does not permit power and low voltage signals to run in the
same conduits or channels. Shielded or not.

Interference? Not much, I would guess.
 
J

Jack// ani

Jan 1, 1970
0
Rene said:
I was told that it is not a good idea to run a power (120 AC) cable together
with an Ethernet cable because the AC cable would disrupt the transmission
on the Ethernet cable.

My ac cable and the utp ethernet cable are running one upon the other,
although this is not considered a good practice, but believe me; I
never noticed any disturbance yet.
Can I buy cables
that already include a shield on them?

Then go for a stp cable.
 
R

Rene

Jan 1, 1970
0
Electrical code does not permit power and low voltage signals to run in
the
same conduits or channels. Shielded or not.

Not even if power is only 12 volt DC?
 
P

peterken

Jan 1, 1970
0
"Power" means "electrical dangerous voltage-levels", in Europe the
"dangerous level" is set to 48V.
Usual indication of "power lines" in this context is "mains supply"...


Rene said:
Electrical code does not permit power and low voltage signals to run in
the
same conduits or channels. Shielded or not.

Not even if power is only 12 volt DC?
 
R

Rene

Jan 1, 1970
0
That is fine how ever, pulsing loads on the DC line could
induce cross talk problems in crappie communication cables like
CAT5 and the like over a long hall.

Even if the CAT5 cable is shilded?
 
W

w_tom

Jan 1, 1970
0
Changing currents of how much will induce what frequency on
adjacent CAT5 wire? Junk science is widespread and prolific
when we forget to apply numbers to our theories. Please
provide numbers for these fields generated by changing loads
on a 12 VDC wire. With those defined fields, what sort of
voltage and current is induced upon twisted pair CAT 5 wire?
Anything is possible in a fiction world where we fear to
provide numbers. Numbers provide a perspective called
reality. What are those numbers?
 
W

w_tom

Jan 1, 1970
0
Don't even worry about shielding. That is 60 Hz field -
very low frequency - induced on tightly twisted pair wires.
Almost no coupling exists. Furthermore any minuscule currents
induced on the CAT 5 wire are made irrelevant by baseband
signaling equipment (NICs) that operate in megahertz
frequencies. What he failed to provide are numbers - the
perspective that makes the problem "insignificant".

Others have defined a more significant parameter - human
safety. Power and communication wires must have some
separation for human safety reasons. Once that necessary
separation exists, then coupling is made even less significant
than "insignificant".
 
P

peterken

Jan 1, 1970
0
Changing currents of a specific frequency on one line will induce induce
identical AND harmonic frequencies onto the other.
The level of induction depends upon the distance between the lines
(reverse-square of the distance)
The intent of "twisted pair" is to have an induced current to be identical
in both wires, thus (theoretically) eliminating a voltage-difference between
both wires of one loop.
Thus the level of induction depends upon the size of the "spike" in one line
AND it's actual frequency AND the "not-perfectness" of the twisted pair AND
the distance between the line and the twisted pair....

One can of course take the datasheets of a specific twisted pair and begin
calculations until your hair turns grey, but that was not the point of this
thread.
The point was to inquire if power lines could be aside datalines and what
were contra-indications to do so, nothing else...
Personally i prefer to leave the math to the designers of the cables, and
just apply "rules of best craftmanship"....

<quote: One can be born silly, then rocked daft in the cradle, and still
study until completely nuttyness arises....>



Changing currents of how much will induce what frequency on adjacent CAT5
wire?
Junk science is widespread and prolific when we forget to apply numbers to
our theories.
Please provide numbers for these fields generated by changing loads on a 12
VDC wire.
With those defined fields, what sort of voltage and current is induced upon
twisted pair CAT 5 wire?
Anything is possible in a fiction world where we fear to provide numbers.
Numbers provide a perspective called reality.
What are those numbers?
 
J

Jamie

Jan 1, 1970
0
peterken said:
"Power" means "electrical dangerous voltage-levels", in Europe the
"dangerous level" is set to 48V.
Usual indication of "power lines" in this context is "mains supply"...





Not even if power is only 12 volt DC?

That is fine how ever, pulsing loads on the DC line could
induce cross talk problems in crappie communication cables like
CAT5 and the like over a long hall.
 
D

Dbowey

Jan 1, 1970
0
Jamie posted:
I guess working 21 years in a lab
performing Lost, Skin, Radiated, and velocity
tests in a work area that has made
electronic wire and cables for 50 years
isn't enough ?
To let you in on something, our
facility was one of the first to
start massive manufacturing of CAT 4,5
and the like along with the foam pairs
bundled with twisted pairs of control
wires etc...
high levels of DC currents pulsing
over long runs bundled in the same
race way with no form of EMF shielded
does un-balance the Twisted pairs there
by influencing the signal.
--

How about sharing some of that vast experience and tell us how induced voltage
unbalances a balanced cable pair by "influencing the signal." What work did
you do in that lab?

Don

--
 
J

Jamie

Jan 1, 1970
0
well if its shielded then you should be ok how ever, most
cat 5 i used is not shielded but that doesn't mean you
don't have a good supply of the shielded type.
 
J

Jamie

Jan 1, 1970
0
I guess working 21 years in a lab
performing Lost, Skin, Radiated, and velocity
tests in a work area that has made
electronic wire and cables for 50 years
isn't enough ?
To let you in on something, our
facility was one of the first to
start massive manufacturing of CAT 4,5
and the like along with the foam pairs
bundled with twisted pairs of control
wires etc...
high levels of DC currents pulsing
over long runs bundled in the same
race way with no form of EMF shielded
does un-balance the Twisted pairs there
by influencing the signal.
 
J

Jamie

Jan 1, 1970
0
Dbowey said:
Jamie posted:


--

How about sharing some of that vast experience and tell us how induced voltage
unbalances a balanced cable pair by "influencing the signal." What work did
you do in that lab?

Don
bandpass, cross over, burn test for smoke, copper purity, rip cord break
with out deforming pairs.
Practical application testing, one of them just happens to be a a
test that requires a length of a 100' to be laid along in side of a race
way
with mounts that have a high current lines. the CaT is placed in a
holder that places it 1 " away from the high current lines which AC and
DC currents are generated up to 500Amps while monitoring the twisted pairs..
this test tell us how consistent the twisted pairs are and how well
they are bunched together. twisted pairs that are not uniform at the
correct the lay will show uneven readings under AC currents..
etc..
P.S.
we are currently making some CAT wire with combined Optics and
rein forced binders made of Kevlar along with some high current control
wires as a composite cable to be used in future homes and businesses.
should be interesting. we have never combined those types of components
in one cable before.
so far, testing on the samples appear to be passing very well on the
CAT and control wires. i think this maybe due to the fact that we have
put lightly braided shield around those.

Btw.
putting Cat wire in a race way that houses high current wires for
drives DC/AC has prevent to not work well for our electricians. it
took them aprox 3 mounts of playing around with a machine that was
having a very slow response rate reading data from controllers via a
Cat 5 . it turned out that, many errors were being generated in the
interface and thus the network connection was doing alot of resends
or waiting for updated readings thus causing the machines performance
to be unpredictable.
running the CAT 5 in its own race way solved that problem.
 
D

Dmitri

Jan 1, 1970
0
Jamie said:
I guess working 21 years in a lab
performing Lost, Skin, Radiated, and velocity
tests in a work area that has made
electronic wire and cables for 50 years
isn't enough ?
To let you in on something, our
facility was one of the first to
start massive manufacturing of CAT 4,5
and the like along with the foam pairs
bundled with twisted pairs of control
wires etc...
high levels of DC currents pulsing
over long runs bundled in the same
race way with no form of EMF shielded
does un-balance the Twisted pairs there
by influencing the signal.

Jamie,

I hope you still re-visit this old post from time to time.
I'd like to learn more about the tests you are referring to. What kind of
currents you are talking about? What do you refer to by pulsing DC in this
case, switching loads? What frequency? What type of load? What was the
distance between the cable with DC current and the twisted pair? What was
the length of the samples? What kind of raceway used? What was the UTP
terminated on, and how did you measure the mis-balance?
From your post I got a feeling that you were talking about tests conveyed
quite a few years back, so I'm sure you'll open no trade secrets by
posting here (or in comp.dcom.cabling to that matter). Very interesting
stuff, please continue this thread.

--
Dmitri Abaimov, RCDD
http://www.cabling-design.com
Cabling Forum, color codes, pinouts and other useful resources for
premises cabling users and pros
http://www.cabling-design.com/homecabling
Residential Cabling Guide
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