Wire types for 12V DC and 24V DC?

On 1 Jan 2003 10:26:10 -0600, Mark Lloyd <mll @godmail.com> wrote in
message  <p8561vg62440ltl9iq8rkpucj2o0i­hn @4ax.com>:





No, you did not make a "correct response about that".

Your mistakes were multiple --as usual -- and -- as usual -- the biggest
one is that you fail to realize that you are the problem.

Please try to stop posting nonsense to this newsgroup.
... Marc
Marc_F_Hult <use @xxxhydrologistxxx.com>

On Mon, 30 Dec 2002 01:48:28 GMT, "Marksman" <marks @insightBB.com>
wrote:

yes if the Run is short and the Current is VERY LOW!

Ron

On Wed, 01 Jan 2003 16:53:07 GMT, "Marksman" <marks @insightBB.com> wrote
in message  <S1FQ9.586426$QZ.83808@sccrnsc­02>:


Marksman,

You are welcome. Sorry for the "noise".

To summarize, there is an emerging standard known as Power Over Ethernet
(POE) that uses 50vdc (+/- ~12%) to power drown stream devices.

If I were powering devices using CAT5, I would try to use the same
conductors (pins 4&5 positive and pins 7&8 negative on an RJ45 plug).

See, for example,  
http://www.nycwireless.net/poe / for detailed construction tips.

HTH ... Marc
Marc_F_Hult <use @xxxhydrologistxxx.com>

On 01 Jan 2003, The voices in the head of  uttered these words to the
inhabitants of comp.home.automation.



        Na, I could see what you were talking about. It was in an odd place
in sentence structure. I have my own pet peaves as well.

--

Robert S. Ely  (Bob)
rsel @optonline.net               robert. @dhs.state.nj.us
New Lisbon Developmental Center     Communications Systems Technician-3
Work Phone:      1-609-894-4057     Work FAX:        1-609-726-0357
ICQ:             33390750           Yahoo Messenger: rsely74

Check out my photos:
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On 31 Dec 2002 12:38:50 -0600, Mark Lloyd <mll @godmail.com> wrote in
message  <p4m31vk1dovmaptv3a752go0acb3n­24 @4ax.com>:

Let me ask you a slightly different question. Why do you continue to do
this newsgroup a disservice by repeatedly posting gibberish and bad advice?

Mark Lloyd continues:

CAT-5 *is* American Wire Gauge (AWG) 24 !

You neither remember, understand, or communicate accurately about
electronics.

Please consider sitting on your hands when such questions are posed instead
of polluting this newsgroups with misinformation because you can't control
yourself.

... Marc
Marc_F_Hult <use @xxxhydrologistxxx.com>

The system isn't mine. It belongs to the facility where I work (hence the
use of "work's"). I guess that's not a valid use?

--

Robert S. Ely  (Bob)
rsel @optonline.net               robert. @dhs.state.nj.us
New Lisbon Developmental Center     Communications Systems Technician-3
Work Phone:      1-609-894-4057     Work FAX:        1-609-726-0357
ICQ:             33390750           Yahoo Messenger: rsely74

Check out my photos:
http://www.shuttercity.com/Sho wGallery.cfm?AcctID=4359

Thank you to everyone for the posts.  It has been helpfull.

On Tue, 31 Dec 2002 20:13:52 GMT, Marc_F_Hult



My mistake was in saying 30V rather than something higher. Also, you
might notice that the original post was about 12V or 24V, so I did
make a correct response to that. It appears that you have the kind of
nasty attitude teenagers often develop (somehow I missed that stage)
and most  people grow out of. I'm not really interested in more
bullshit, so will no longer post in this thread.



--
Mark Lloyd
http://go.to/notstupid
http://notstupid.laughingsquid .com

"religion is a socio-political institution for the
control of people's thoughts, lives, and actions;
based on ancient myths and superstitions perpetrated
through generations of subtle yet pervasive
brainwashing."

On Tue, 31 Dec 2002 21:07:23 GMT, "Robert S Ely (Bob)"

Sorry for the mistake. These problems (inappropriate apostrophes) are
REALLY common. I guess I got a little oversensitive.

On Tue, 31 Dec 2002 15:31:13 GMT, "Robert S Ely (Bob)"

I've made measurements on the phoneline here. While 'on-hook' there
was -50VDC. While ringing it was 75VAC. Since the DC is still present,
that would mean a variation between -25V and -125V).

--
Mark Lloyd
http://go.to/notstupid
http://notstupid.laughingsquid .com

"religion is a socio-political institution for the
control of people's thoughts, lives, and actions;
based on ancient myths and superstitions perpetrated
through generations of subtle yet pervasive
brainwashing."

On Tue, 31 Dec 2002 05:49:52 GMT, Marc_F_Hult



And why don't you ask me that directly?

Looks like I was off some here. I see from other posts that CAT5 will
work with even higher voltages.

How much current can you get from that phoneline? You might consider
that thare's a lot of voltage drop when the line is loaded (that's how
the telco knows your phone is 'off-hook').

I remember from my electronics classes that 24 guage wire will handle
1.5A. The wire in CAT5 is smaller, so I was estimating from that.

--
Mark Lloyd
http://go.to/notstupid
http://notstupid.laughingsquid .com

"religion is a socio-political institution for the
control of people's thoughts, lives, and actions;
based on ancient myths and superstitions perpetrated
through generations of subtle yet pervasive
brainwashing."

On 30 Dec 2002, The voices in the head of Mark Lloyd uttered these words
to the inhabitance of comp.home.automation.

Keep in mind that analog phones on most PBX systems run at 48VDC over that
wire with 90-120VDC rung voltage (Fluctuating DC 20Hz (I believe)).

--

Robert S. Ely  (Bob)
rsel @optonline.net               robert. @dhs.state.nj.us
New Lisbon Developmental Center     Communications Systems Technician-3
Work Phone:      1-609-894-4057     Work FAX:        1-609-726-0357
ICQ:             33390750           Yahoo Messenger: rsely74

Check out my photos:
http://www.shuttercity.com/Sho wGallery.cfm?AcctID=4359

On Tue, 31 Dec 2002 15:28:23 GMT, "Robert S Ely (Bob)"



Thank you for for the above contribution (I think) to my online
collection of completely inappropriate apostrophes. I'm sure you don't
want the credit for such a mistake.

On 29 Dec 2002, The voices in the head of Joe Keenan uttered these words
to the inhabitance of comp.home.automation.



I do a similar thing with my (work's) voice paging system. The Valcom
speakers use 24VDC and as much as 1A to power small amplifiers that are
part of each speaker. (www.valcom.com) I use the brown pair for the power
and the blue pair for signal. Works like a champ and doesn't seem to bother
anything else in the rest of bundled cable run.

--

Robert S. Ely  (Bob)
rsel @optonline.net               robert. @dhs.state.nj.us
New Lisbon Developmental Center     Communications Systems Technician-3
Work Phone:      1-609-894-4057     Work FAX:        1-609-726-0357
ICQ:             33390750           Yahoo Messenger: rsely74

Check out my photos:
http://www.shuttercity.com/Sho wGallery.cfm?AcctID=4359

On 29 Dec 2002 23:31:14 -0600, Mark Lloyd <mll @godmail.com> wrote in
message  <pbmv0v4prdh98d8413vud6gepbuju­70 @4ax.com>:

What does it mean when Mark Lloyd proclaims that "CAT5 should be good for
up to 30V (class 2)" ?

US National Electrical Code (NEC) "Class 2" circuits are "less than 50
volts" AC or DC) -- not 30 volts. See NEC Article 720.

Power 0ver Ethernet (which in commonly run using CAT-5) is nominal 44 to
57vdc.

All traditional US telephone company wiring has -48vdc. Is Mark Lloyd
suggesting that we can't use CAT-5 for telco wiring?

See http://www.sandman.com/telco.h tml for a list of devices designed to be
powered from the 48vdc source provided by every US telco. (TELCO POWERED???
TOOTHBRUSH anyone?)

What is the basis for Mark Lloyd's "800mA" pronouncement ?

... Marc
Marc_F_Hult <use @xxxhydrologistxxx.com>

For such as long cable, I'd try to put the power supply closer to the
load.

The one I have working at the moment is the 80-foot cable to the
Target camera. I used the existing connection (it works even with the
power supply 80 feet from the camera).



--
Mark Lloyd
http://go.to/notstupid
http://notstupid.laughingsquid .com

"religion is a socio-political institution for the
control of people's thoughts, lives, and actions;
based on ancient myths and superstitions perpetrated
through generations of subtle yet pervasive
brainwashing."

On Mon, 30 Dec 2002 14:10:31 GMT, todesco <tode @attbi.com> wrote in
message  <3E1053FC.F6700 @attbi.com>:



Nyet.

Last I knew, the resistance of 24 gauge unplated copper wire in
CAT-5/CAT-5E/CAT-3 was about 25 ohms per 1000 foot depending on stranding
and temperature. It may be spec'd to allow as high as 28 ohms/1000ft. That
is, about 5 ohms per 200 feet -- not 10 ohms as todesco states.  

So the voltage drop is 200ft*0.025ohms/ft * 0.8A =  4 volts (not 8 volts as
todesco states).

So a 13.8VDC source (the "float" voltage for lead/gell cell battery
commonly used in HA/security installations) will only drop to about 11.8
volts at 400ma current at the end of 2*100 = 200 feet of CAT-5. I speculate
that this is within the "12VDC" voltage requirement of the majority of
devices out there. Using two conductors each for + and ground would
maintain ~11.8VDC at 800ma draw at the same length.

If the load is dynamic, it is usually a good idea (and sometimes mandatory
or even insufficient) to add a capacitor at the device being powered to
reduce the apparent source impedance.

Another solution is to use a DC-to-DC converter. There are many different
configurations available (12vdc to +/- 15vdc, 5vdc to 12vdc, etc).

The IEEE proposed standard for and extant implementations of Power Over
Ethernet (POE) use a 44 to 57VDC source.  
See eg .
At the device being powered, a DC-to-DC converter is used to derive
whatever voltage is needed.

... Marc
Marc_F_Hult <use @xxxhydrologistxxx.com>

On Mon, 30 Dec 2002 01:48:28 GMT, "Marksman" <marks @insightBB.com>
wrote:

CAT5 should be good for voltages up to 30V (class 2). The problem is
current, which shouldn't exceed about 800mA per wire.

--
Mark Lloyd
http://go.to/notstupid
http://notstupid.laughingsquid .com

"religion is a socio-political institution for the
control of people's thoughts, lives, and actions;
based on ancient myths and superstitions perpetrated
through generations of subtle yet pervasive
brainwashing."

It depends on the device's required current, and the distance to the device.  I
use it all the time for alarm keypads and glassbreak sensors.  They are home run
to the power source.  Not daisy chained.  For cameras I home run 18X2 with an
RG-59Cu, but there are many here who have used just Cat 5 with baluns for
cameras.

--
Bob La Londe

The Security Consultant
http://www.diycomponents.com
849 S Ave C
Yuma, Az 85364

(928)782-9765 ofc
(928)782-7873 fax

ROC 103044, C-12
ROC 103047, L-67

And, more importantly, how much voltage drop can your application
tolerate?
At about 5 ohms per 100 feet (actually, 10 ohms for the feed and
return),
you can get significant voltage drops.  Using the 800ma example, that
would give you abut an 8 volt drop using Ohm's Law.  That is
voltage = resistance times current (V=IR).    

That's what I get for grabbing the 1st ohms/gauge list on the search
list.  They must have meant 5 ohms for both the feed and return.
I should have known better.

Depends on how much power the device needs.  The only time I've actually
done this is with a wall-mount phone w/ digital answering system.  I had
a cat-5 run to the location, and used two pair to wire the jack as
normal.  I used the other two pair (doubled up) to run DC power to the
phone, mounting the wall-wart near the phone patch panel.  No problems
at all, but the phone doesn't take much current.

joe

What is the max voltage/current to run through the cat 5?