Structured Home Wiring

Security System / Burglar Alarm - Sample DSC Alarm System

This guide uses the DSC Power 864 security system with DSC accessories as an example to detail exactly how to wire a security system. Actual wiring diagrams and pictures are provided for real DSC products. This guide assumes that all of the components will work together. See the Alarm Wiring guide for more information.

This is the master wiring diagram for a Power 864 main panel. The Power 864 supports 64 different zones, but only 8 zones are available with the main board. Additional boards would have to be purchased to expand this system. This panel contains connections for power, the siren, keypads, devices, and sensors. Each will be covered in detail below.

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Alarm Panel Power Wiring

The power connections consist of the AC power and the backup battery. Note that I am working from the left to the right on the circuit board, but the power should be the last thing you connect.

For this alarm system, the wires for the battery come directly out of the side of circuit board. First, verify that the power requirements of the circuit board match those of the battery. In this case, they should both be 12 volt 7 amp-hours. Buying the recommended BD7-12 battery or purchasing the battery, power supply, and main board in a kit is easier. The wire colors will be red & black which match perfectly the red and black terminals on the battery itself. Connect the ground first (black), and then the power (red).

Using 18 AWG or better wire, measure the length of wire needed to connect the power supply at the power outlet to the power terminals on the circuit board. First connect the wires to the power supply, then the wires to the alarm panel, and then finally plug in the power supply to the electrical outlet. The power supply will either have 2 screw terminals (+, -) or 3 terminals (+, -, ground). Typically, both the power supply and alarm panel will have power connections labeled + and -. Connect the + terminals together and the - terminals together. Usually your power wire will be colored, labeled with + or -, or will have a stripe (for power) to differentiate the positive and negative wires.

For this alarm, the ground is located at the opposite end of the circuit board. You could run the ground from the ground connector on the power supply and it will work since this ground will run back to the electrical box and then to the building's main ground. I prefer to tap directly into the building's main ground. This is easy for me because my wiring panel (which is only a couple of feet from the electrical box) already has a direct ground connection for other wiring. Tapping the building's main ground normally means clamping a wire to the copper water pipe as a ground or connecting it to a driven ground rod. There is no need to figure this out for yourself. Your home should already have a VERY thick wire that is clamped to this ground connection and run to the electrical box. Also, any coaxial cables for cable TV or satellite will also be grounded right as they enter the home and you can either leverage that ground or trace it back to the grounding clamp. Finding a good ground is another good reason to locate the alarm panel with other wires in a basement or utility closet.

The alarm system also recommends that you also ground the metal alarm panel box. This is done in case a power wire comes lose and contacts the cabinet. With the cabinet grounded, that lose wire will be grounded in case it comes in contact with the cabinet. To ground the cabinet, connect a ring connector to the end of the ground wire. Then, cut another short length of wire and connect a ring connector to one end of that wire. Using one of the existing holes in the cabinet (alarm panel box), bolt both wires to the cabinet as indicated above: bolt, cabinet hole, star washer, long ground wire to building ground with ring connector, lock washer, nut, short ground wire with ring connector, lock washer, nut. For this specific alarm system, all of these parts were included in the kit. Note: The star connector is required to scratch the paint off of the cabinet. Paint doesn't conduct electricity.

Note that there is a hole located at the top of the power supply housing. If your wall outlet has a screw in the middle of the wall plate, then you can remove that screw, plug the power supply into the bottom outlet, and then put the screw through the hole in the top of the power supply and back through the wall plate. This prevents the power supply from falling out of the outlet or someone removing it by mistake. Also make sure you don't use an outlet that can be turned off by a wall switch.

Alarm Siren/Horn Wiring

The siren/horn/bell for the system basically makes lots of noise when the alarm goes off. As before, if the siren didn't come as part of a kit, then verify that the siren doesn't draw too much current for the panel, in this case no more than 700 milliamps. This means that the siren must be labeled 700 mA or less.

The siren will either have + and - terminals or black (-) and red (+) wires coming out of it. Connect these wires to the black and red wires of the alarm wire that runs back to the + and - bell terminals on the main panel. For this example, the siren also has an optional yellow (+) wire that can be used instead of the red wire. Using the yellow wire makes a yelp noise and the red wire makes a steady tone.

Alarm Keypad Wiring

Keypads typically require 4 wire connections. For multiple keypads, run each wire from the keypad back to the control panel and simply place multiple wires in each connection. The terminals on the keypad are labeled Z G Y B R. The G (Green), Y (Yellow), B (Black), and R (Red), are the standard 4 colors for alarm wiring. The DSC Z model keypads contain a 5th Z connection that can be used to monitor an additional zone. Remember that the Power 864 panel supports up to 64 zones but only has connectors for 8. The sensor wiring description below details how to use the Z terminals.

Alarm Device (Smoke Detector) Wiring

The Device terminals are for smoke detectors and other programmable devices. Below are the instructions for wiring 2 or 4 wire smoke detectors to a DSC alarm. Consult your alarm manual for any specific instructions on wiring programmable devices.

Alarm Sensor Wiring

All sensors use the COM (common) Z connectors on the control panel circuit board. Powered sensors (Ex: motion detectors) also require the + & - auxiliary power connections. All 4 COM connectors on the board are identical and any of the can be used. The idea is that Z1 & Z2 use the first COM terminal, Z3 & Z4 use the second...

At the alarm panel side, connect the wires using the colors shown below. Door and window sensors don't require Aux Power, so don't connect the red and black wires. You may be tempted to connect these wires when unused just to get them out of the way. That is a bad idea, because it means there will be live +12V power at the other end of that wire. A short could cause the alarm to malfunction or a short could damage the circuit board.

Below are sample DSC sensors: Motion Detector, Glass Break Sensor, Window Sensor, and a Door Sensor. Specifics for wiring each type of device follows. Be sure to read our sections on Alarm Wiring and Tamper Proof Wiring before you do any wiring yourself.

Non-powered sensors like door and window sensors come in 2 parts. The first has 2 wires or 2 connectors on it that connect to the green and yellow wires from the alarm panel. It doesn't matter which wire goes to which connector. The second part of the sensor contains a magnet. It is best to wait to permanently mount the second part of the sensor until the alarm system is running and you are able to verify proper placement.

The motion detector above and the glass break sensor below use all 4 wires. The extra 2 wires are for power. As indicated in the control panels diagram, the power draw for all powered devices (including sensors) cannot exceed 550mA. As and example, this motion detector can draw up to 20mA and the glass break sensor can draw 32mA so there is plenty of headroom for many sensors.

The Normally Closed (NC) connections are preferred over Normally Open (NO) ones. Cutting a wire to a NC sensor will set off the alarm while cutting a wire to a NO sensor will disable that sensor.

This glass break sensor also includes a tamper connection that can be wired as a separate zone or in series with the Normally Closed contacts. Wiring the tamper circuit to the alarm will activate the alarm when the cover of the sensor is removed.

Phone Wiring

The phone connection is required so that the alarm system can call the alarm monitoring company when the alarm goes off. Even if you are not paying for monitoring, you will want to make the phone connection. Otherwise, the control panel will detect this missing connection as a problem and the Trouble light on the alarm will stay lit.

If you have an phone outlet available, the easiest way to make the phone connection is to take a spare phone wire and cut off one of the ends. Then strip the wires and connect the cut end to the control panel. Otherwise, run the wire from the alarm panel to any phone wire you can find in the basement and make the connection there.

The phone wire colors on this alarm (at least for Line 2) don't match standard phone wire colors. Also, in new homes many builders use Cat5e cable for phone wire. It is easier and cheaper to buy one large spool of Cat5e cable and use it for both Internet and phone lines. Your own phone wires can be any color. Just make sure that you match up the correct colors when using different types of wires.

This model of burglar system was chosen because it is one that I am personally familiar with and I had parts and manuals that were available for review. These instructions are provided as an example for how to interpret instruction manuals for different alarm systems so that you will have a better understanding of them. It is not intended that you blindly wire an alarm system exactly as described above. Small changes to the control panel or components may occur over time, so always reference the manual that came with your hardware before this site. Also, please review the general disclaimer.

This example is not intended as an endorsement of DSC and this site is not affiliated with DSC. DSC (Digital Security Controls Ltd.) is a division of Tyco International.