# Cat5e data cables for Alarm power and control circuits?



## meipaul (May 8, 2011)

I would like to use cat5e 4 pair 24 guage cable plenum rated to feed from my access control panels out to doors for my readers, door contacts and audible alarms.
my Cat5e cable is a west Penn 254245 300 volt CMP rated cable.
I find no NEC code that would prohibit me from using data cable in instead of a 22-2cd or 6cd 22.

Of course we have been using Cat 5 cable for years feeding the cameras for both video and power. Now that we are using power over the ethernet POE it seems to make sense to just convert over totally to data cable. My power load of 24vdc needs are minimal under 25 watt.

This is for large projects such as schools K-12


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## HARRY304E (Sep 15, 2010)

meipaul said:


> I would like to use cat5e 4 pair 24 guage cable plenum rated to feed from my access control panels out to doors for my readers, door contacts and audible alarms.
> my Cat5e cable is a west Penn 254245 300 volt CMP rated cable.
> I find no NEC code that would prohibit me from using data cable in instead of a 22-2cd or 6cd 22.
> 
> ...


It looks like you are good to go but double check 300.22(C) NEC.



Welcome to the forum..:thumbup::thumbup:


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## meipaul (May 8, 2011)

Thanks, The Plenum cable was not my question it was using the 24 guage data cable in place of 22 guage two, 4 or 6 conductor that I normally use. Not a wire guage issue for power load either. Both are rated by West Penn as communications cable.
We think of Data cabling being used for only devices that are ethernet based like IP cameras and POE edge devices. But if you simply need 8 conductors to a door with alarm devices I want to use Cat5e instead of an 8 conductor 22 guage.
I am looking to standardize as we continue to roll out using data cabling for most all hardware. Also it future proofs the installation ine the event that the hardware at the edge becoms ip based. We currently install cat5e to all cameras even if they are analog cameras requiring one pair video and one pair power. In the event that this camera ever gets replaced with an IP camera the cable is already in place, as long as we keep th cable under 100 meters.


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## Electric_Light (Apr 6, 2010)

I don't know what voltage POE uses, but your load is pretty much around 1A.
I'm sure POE equipment are designed to accommodate high voltage drop associated with the use of ethernet 
24AWG is ~25ohm/1,000ft, so thats around 50ohm/1,000ft since its a "round trip". 

For a 100' (33m) run, that's around 5v drop, which is around 21%. 

If you parallel up all four pairs, you can get by with 10.5% drop over a 200' run. Set up the power supply to +10% at 26.4v so you won't exceed the top end of +/- 10% under very light load, but still remain within the bottom end of +/- 10% under full load. Obviously you're going to have to make adjustments based on allowable tolerance for your equipment. 

If you really want to do longer, you need an active-regulating power supply with a feedback input (as done on 3.3v bus on computer power supply) to measure voltage at load-end and adjust voltage at power supply end continuously so that the voltage at load-end stays at set voltage.


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## Jlarson (Jun 28, 2009)

Electric_Light said:


> I don't know what voltage POE uses...


POE uses 48 VDC


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