RJ45 and Cat5 power rating

[Brian]

HI

I have been looking about and can't find the answer and was wondering
if anybody could point me in the right direction.

I'm working on a project where I want to use RJ45 and cat5 cables

I want to use 1 pair for the differential data and 3 pairs to carry power
(in parallel)
but I'm not sure on the power rating of CAT5 cable or the RJ45 connectors.

Does anybody know?

Brian

[Jamie]

Post by Brian
HI
I have been looking about and can't find the answer and was wondering
if anybody could point me in the right direction.
I'm working on a project where I want to use RJ45 and cat5 cables
I want to use 1 pair for the differential data and 3 pairs to carry power
(in parallel)
but I'm not sure on the power rating of CAT5 cable or the RJ45 connectors.
Does anybody know?
Brian

its low current wire.
i can't remember the common gauge on the conductor but its
around 24 awg. its ~ 25 ohms per 1000 feet
it is suggested that you do not exceed 5 % drop of voltage
on the other end.
it depends on the length of cat your going to use.
longer lengths means less current handling.
you can put the pairs together, i have seen it done but
don't expect to run lots of current.
for example, for a 100 foot run i wouldn't go over 2 amps/
with 3 pairs together you will get aprox 16 ohms of resistance
on a 1000 foot run so in a 100 foot run you would get 1.6 ohms.
so you mite get like a 3 volt drop if you expect a load
of 2 amps in the line for example. you didn't say how large of
a load you were expecting to use ?
i may have the gauge used for Cat wrong, it could be 22 which would
make it even better for you.
hope that give you some insight there.

[jasen]

Post by Brian
I want to use 1 pair for the differential data and 3 pairs to carry power
(in parallel)
but I'm not sure on the power rating of CAT5 cable or the RJ45 connectors.
Does anybody know?

you could look to a maker for their data sheets...

here's a starting point:

Voltage up round 100VDC (peak of telephone ring signal)

current about 250mA per contact (power-over-ethernet spec puts 500mA at
48V common-mode on one pair coming and another going -
less than that has been fatal)