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In new construction, how is pre-wiring done for alarm systems, when then alarm may not be installed right away (or ever)?

It makes sense to me to actually install recessed door contacts (they're only a few dollars each) and run the wiring back. I suppose if using window sensors it would make sense to do those as well (or just use motion sensors / glass break sensors and save a lot of work).

It also makes sense to run at least a couple wires up into the attic, for a siren or other future use.

What I'm not sure of is motion detectors. What's the best way to leave the wires to be able to hook them up later? Any tricks to avoid cutting a giant hole in the wall later?

Any other considerations to pre-wiring?

Aarthi
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gregmac
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3 Answers3

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When we do drywall, if there's a loose wire (e.g. electrical line for a hard-wired dishwasher), we cut a small hole and pull it through during installation. Pretty easy to do while everything is open and you can see both sides of the drywall. Leave plenty of slack so it can be fished through the drywall before it's been attached to the wall, and the hole can be made even smaller.

The other option is installing a J-box like you would for phone or cable wires, and leave an opening in the drywall like you would for any other J-box.

For other considerations, I'm a huge fan of conduit. No need to go to every door/window, but it wouldn't hurt to run some to where you want the main key pad, to the attic, and to your telecomm connections.

BMitch
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I pre-wired my house for an alarm since the alarm got fitted at the very end. I figured it would reduce the work required for the final install. I installed wires for the motion sensors, reed switches for under-house access, the control panel and the siren. From memory, some units require 6-core (such as the control panel) and some 4-core so I think I just ran 6-core everywhere.

Since I knew the alarm I was going to install and knew where the sensors and control panels would be, I ran the cables to those locations and just left them there to be plastered over.

For the motion sensors, I had roof access so it was easy to poke a hole though the ceiling at install time.

For the panels, I positioned these near light switches. At install time, it was easy enough to locate the cables (near the power lines) and pull them though the hole in the wall used for the control panel.

The reed switches were under the house so also easy to wire up.

The alarm unit also required a phone line and power. Part of my plan was the location where the unit would live so I ensured the sparky wired phone and power to the appropriate location.

I had an alarm guy install the actual unit. Having the wires pre-laid reduced costs, though he added a screamer to the system.

I did not bother with window or door sensors since I have a lot of windows/doors and the motion sensors will trip once the guy enters the house anyway.

BTW: I put coloured PVC tape on the wires at 2~3 metre intervals to make it easy to identify what cables went where.

BTW2: I have a (renovated) 1920s house with sizable cornices. In one location, the plasterers incorporated the senor cable into the cornice, allowing the sensor to be attached to the wall rather than hanging from the ceiling. This looked a lot nicer, I wish I had done it everywhere.

dave
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We simply leave slack through a nm staple and bring the end to nail that is hammered into the corner of the stud. Dry wall guys do a good job at avoiding pinching the wire but if not just pull out the slack.

Matthew
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