Motion sensor question?

If I wanted to add some new motions to a security system, could I use cat5e cable which is 24AWG for it because the max ampere that the motions will use is about 50ma total and I know the run will be less then 1000 ft. If not then should I use 22?

This begs the most famous question on this board… :lol:



Is it being used as an actual security system? Or is it your demonstration system?

If it’s your actual security system protecting your house, I wouldn’t recommend it. If it is a demonstration system that is on a board, It will be alright.

I’ve seen it used before but wouldn’t recommend it. Cat5 is really small conductors for one, and it’s a waste of copper. You’re not going to use 50% of the cable and just throwing money away. Just use some 22/4 alarm cable and you’ll be fine. If you need a little bit, send me a PM and we can work something out. On a side note, I’ve seen electricians wire doorbells with Cat5 and I just shake my head!

Also, when you do install the motions, make sure you seal up all holes in the back including around the wire. You want the motion detector to be air tight. Spiders love to make homes in them and just causes false alarms. Best thing I’ve found to use is this grey gummy sealant they use on air ducts.

Thanks, I brought up the cat5e cable because I already have a big role of it and wouldn’t need to go out and buy some new wire, plus since the cable has 8 conductors in it I could use 4 for feed and 4 for return so I wouldn’t have to run two wires up to it.

Why would you need to feed and return?

I have 12vdc and zone coming from the panel to the first motion, and then 12vdc and zone coming out of the first motion and going to the second motion. One cable going to it with 8 instead of two with 4. Two motions one one zone. Can make splice in the basement for it .

You would just use a 22/4 cable from the panel to the first motion detector, then another 22/4 cable from the first motion detector to the second. There is no need for the second set of 4 conductors.

I know I could do that I just thought I would use what I already had, thanks.

Ah, I understand. However, you still need to be careful about the terminals on the motion detector. They will have a maximum and minimum gauge of wire that can be accepted in the terminal, denoted as 18-22 AWG, 12-18 AWG, etc. The small terminals for security devices are often 18-22 AWG, while CAT 5 cable is usually between 22-26 AWG, 24 AWG nominal. This means the terminal may not grasp the wire correctly, resulting in a poor connection.



Again, it is possible to use CAT 5 for this application, but there are things you need to watch out for, and it is certainly not recommended.

Great thanks

Couple of things too… I would avoid putting two or more motion detectors on the same zone. Motion detectors are usually the cause of false alarms, and having more then one on a zone makes finding the culprit more difficult. Not sure how your system is zoned out, but combine windows or doors to free up a zone if needed. Also, try to home run each motion back to the panel. You will still only need 4 wires for each. Just makes troubleshooting a lot easier if all the wires and connections are back at the panel.

ok, I will do that I have 3 free zones available. Also what is the best way to secure this wire, because the insulated cable tackers look a little large for that size of cable. Would you now which kind, thanks.

I find the best method (especially if you have several cables to secure) is to drive a Romex staple parallel to the run of the wire with nothing underneath, leaving about a 1/4" gap. Then take your cable and a wiretie and secure the cables to the staple. They end up “floating” underneath but the good thing is it doesn’t damage the cable and if you ever need run another wire, you simply cut off the wiretie and attach the new cable.

I just received the motions today and was flipping through the manual. It says that you should use 22 AWG like your were saying but then it says the wire has to be a minimum of 0.5mm in diameter which 24 AWG is. Also below it gives you a chart that says you can use 24 AWG for runs under 200m which is what I am doing. Since it says it in the manual am I allowed to use 24 AWG?

Usually, you always go by the manual! That way when things go wrong and you’ve followed all the specs in the manual, you can blame the manufacturer. I would figure they wrote and designed everything under metric figures (seeing as it is DSC and probably designed in Canada) and then converted to AWG. So I would say you are safe with using the 0.5mm figure. I bet the “22” is a typo, seeing as the chart more accurately reflects the right conversations.

That is what I figured, thanks for the help.

I know this is an old thread, but I felt that I should put in my two cents based on real world, on-the-job experience.



An e-call system with smoke warning for senior living facilities which I serviced at my former job used UTP wire exclusively. Either cat3 or cat5. The current draw on the corridor wireless pendant receivers was high enough that the manufacturer recommended pair 1 for the serial data and tripling the power with the remaining 3 pairs. Their engineering department figured the effective gage was nearly 18 awg.