What gauge wires are you using for sensors?


Senior Member
Forgive the 100 questions, hopefully it calms down once I get some basic stuff done.

How thin can I go on the gauge for my sensors? I bought a spool of 14 gauge, but I'll have ~30 or so sensors all-in [smoke, window, motion, door, heat, CO] and I can see that being pretty darn tough to run into the Elk.

Google shows an 18gauge or larger recommendation - how long are folks running wires that thin? I have a 35' average run, some could be 50-70'.
IVB I had someone else install my alarm wiring but I think they use 22 AWG 4 conductor solid wire for all contacts and to the keypad however I ran few extra cat5E to keypad in case I do something later and need them..I think 14 wire is way to large...my maximum run to where the elk is would be about 55-60 feet, I'll wait for an expert to answer as I could be wrong.
Hi Ivb

Personally iwould use the larger gauge....Here in Oz i use 14/.020....A lot of the cheapie installers would use the 7 /.020 which i assume in the 14 gauge your referring to...

You would probably be able to use it ...But i wouldnt use it for anything with a bit of current such as electric strikes .....

For sensors, don't worry about the electrical characteristics of the wire. It's the physical characteristics that count. Pick something that is easy to run, and most important, won't break.

I've run sensors over thousands of feet with 28 awg. The current is so low and the alarm panels tolerance is so wide, that voltage drop is insignificant.

But as Frank says, if you use them for door strikes, that's a different story (though they also give you a lot of latitude there, as well).
Rocco is right. For sensors almost anything will work. 22AWG is the 'standard' I believe in the alarm industry. I have 22AWG over 100 feet in some cases. 14AWG is for your 15 AMP AC! I posted somewhere a chart that shows the gauge wire you need depending on current - I'll see if I can find it and edit this with link.

There is great information in the articles section of this forum(wiring your house 101) by electron(created by jlehnert) that contains an excel sheet(wire xref.xls). It's a summary of what wire is recommended and what other wires will work.

Are you putting motion detectors in each room for HA? I have been following your projects and wondering how, why and where you are mounting some of your equipment.

Wow - thanks for all the replies and guidance! I'll check out that spreadsheet.

I got the 500' of 14gauge cuz HD had it on sale. I didn't even notice til I got home that it was rated at 600V, or just a bit higher than I need.

I'm going to be using this for all the low voltage smoke/heat/CO/motion/door/window sensors, sounds like I definitely need to get something thinner there. I'll check out the 18/20g wire.

jm9: I'm going to take a pic when it's done, but I put the Elk in my wiring closet next to all the HAPC stuff. I've also decided to NOT put a 2nd box next to my current ADT system, primarily for resale purposes. I'll run a 2nd set of wires to the existing motion detectors, run back to the primary Elk. This way I can say that I have both an Elk and an ADT, if they want the ADT hooked up they just have to hire someone to switch the wires back to the ADT line.

I'll be putting smoke, temperature, motion, window in each bedroom, as well as in various places throughout the house. The temp is there b/c I have a notorious issue with heat flow/leakage through the house, but I'm having a hard time figuring out how the heat flows. This will allow me to not only monitor the heat flow, but I'm hoping to also use whichever room I want to be the target for the HVAC temperature monitor.

Of course, that's all a ton of smack-talking from someone who spent an hour trying to get ElkRP to work, only to realize there's an on/off switch on the Elk...
I run 22/4 solid to each contact/sensor. Four conductors at a contact point give you a ground and the ability to place three switches. A french door requires two switches. A double hung window with a small bottom opening for ventilation requires three switches. The intermediate ventilation open position, also good for sliding doors, is a nice touch for customers. Four conductors at a PIR gives you a ground, switch contact, power, and a tamper. If you are concerned about voltage drop it would be best to add an auxillary power supply. Remember to common the negative terminals on the battery connected to the ELK and any auxillary power supplies.
If you have a lot of zones, the wire management can become a nightmare if you use those larger gauge wires. Here is a pic of my friend's wiring closet after we finished running the security, coax, & Cat5e cabling. We used 22 gauge wiring for the security (two and four conductor green and yellow jacket). I can't imagine all those runs using larger diameter wire. ;)

One note, if you go with to small a gauge, the wire is not as durable which can lead to opens and shorts if you are not very carefull with the wiring runs. He also specified stranded over solid as he felt it to be more flexible. We will just tin the ends (with solder) before we terminate them into the terminal strips.

BTW; he will have 45 Elk M1 zones (had to get two zone expanders), three keypads (one being the smaller, new one), and four Elk Echo speakers (voice announcement), three sirens, and one exterior flasher.

I also got an additional Elk 12 volt power supply (with battery backup) along with two 12 volt power distribution boxes (with resettable breakers) to help distribute the 12 volts throughout the home.


  • cocwire1.jpg
    90.8 KB · Views: 76
I suspect you got mislead by google because you mixed different types of sensors. A general rule of thumb is 18 gauge for anything that is powered (smokes, motion detectors, etc), and 22 gauge for contacts.