Alarm Wire for Door Contacts
If you’re wiring door contacts for a security system, you’re probably wondering which alarm wire you actually need. The good news is this is one of the simpler parts of a security install. In most cases, there’s a clear, reliable choice that works well and keeps things easy.
You can browse all available options in our alarm wire collection.
The Best Alarm Wire for Door Contacts
For most door and window contacts, 22/2 stranded alarm wire is the best choice.
It’s the wire most installers reach for because it does exactly what door contacts need, without adding cost or complexity. It’s flexible, dependable, and made specifically for security wiring.
Recommended: 22/2 Stranded Copper Alarm Wire
Upgrade option: 22/4 Stranded Alarm Wire (helpful if you want extra conductors for the future)
Why 22/2 Alarm Wire Works So Well for Door Contacts
Gauge: Why 22 AWG Is Usually Enough
Door contacts don’t draw power the way devices like cameras or sirens do. They’re simple open-and-close switches that send a signal back to the alarm panel. Because of that, 22 AWG is more than capable of handling the job.
- It easily handles the very low current involved
- Voltage drop is rarely an issue on typical door runs
- The thinner size makes pulling and routing the wire easier
Thicker wire like 18 AWG will work, but for most door contacts it doesn’t really give you anything extra.
Conductors: Why 2 Conductors Is the Standard
Most magnetic door contacts only need two wires:
- One wire to carry the signal
- One wire to complete the circuit
That’s exactly what 22/2 alarm wire is designed for. If you specifically need a solid-conductor option, you can also use 22/2 solid alarm wire in straight, protected runs.
You might consider more conductors if you:
- Want spare wires available for future changes
- Plan to add another sensor at the same door later
- Are pre-wiring a new build or remodel
Stranded vs Solid: Which Is Easier to Work With?
For most door contact installations, stranded alarm wire is the preferred option.
Door frames, wall cavities, and tight turns are common in security installs. In these situations, stranded wire is often easier to route and handle during installation.
- Bends more easily around corners and door frames
- Handles minor movement or adjustments without issue
- Is generally easier to work with in tight spaces
Solid alarm wire is also widely used and performs well in straight, protected runs. When flexibility is needed, many installers choose stranded wire for convenience and ease of installation.
When It Makes Sense to Use 22/4 Instead
While 22/2 is perfect for most door contacts, 22/4 alarm wire can be a smart upgrade in certain situations.
- You want extra conductors for future expansion
- You’re pre-wiring a home or commercial space
- You may add another device near the door later
- You like having backup wires available
If you prefer solid conductor cable for straight runs, 22/4 solid alarm wire is also an option.
Many installers use 22/4 by default for new construction because it saves time and effort if changes are needed later.
Things to Watch Out for When Wiring Door Contacts
Door contacts are simple devices, but a few common wiring mistakes can make installation harder than it needs to be or cause issues down the road. Here are a few things worth avoiding.
Using Thermostat Wire
Thermostat wire is often solid conductor and isn’t designed specifically for security systems. It can be stiff, harder to route through door frames, and more likely to cause frustration during installation.
Using Solid Alarm Wire
Solid alarm wire is commonly used and works well in straight, protected runs. In areas where the cable needs to bend around door frames or tight spaces, many installers prefer stranded wire for easier handling.
Overbuying Fire Alarm Cable
Fire alarm cable is built for different code requirements and typically costs more. For standard door contacts, it doesn’t provide any extra benefit and is usually unnecessary.
Recommended Alarm Wire for Door Contacts
With those pitfalls out of the way, choosing the right wire is straightforward. These two options cover nearly all door contact installations.
Best Overall Choice
- 22/2 Stranded Alarm Wire
- Copper conductors for reliable signal
- Flexible jacket for easier installation
- Designed specifically for security systems
Upgrade Option (Plan Ahead)
- 22/4 Stranded Alarm Wire
- Extra conductors for future expansion
- Ideal for pre-wiring and remodels
If you want the simplest, most common solution, 22/2 is the go-to. If you like having extra flexibility for future changes, 22/4 is a smart upgrade.
Common Questions:
Can I use 18 gauge wire instead?
You can, but it’s usually more than you need for door contacts. Most installers prefer 22 AWG because it’s easier to pull and works perfectly for low-current sensors.
Do I need plenum-rated alarm wire?
Only if the cable runs through a plenum air space. For standard walls and door frames, non-plenum alarm wire is typically fine.
Can alarm wire for door contacts be run outdoors?
If the wire will be exposed to weather, moisture, or sunlight, use an outdoor-rated or UV-resistant cable. Indoor alarm wire is not designed for outdoor conditions.
Can I run multiple door contacts on one wire?
In many systems, yes. Door contacts are often wired in series. Always follow your alarm panel’s wiring guidelines and label your wires clearly for easier troubleshooting later.
Final Recommendation
If you want a simple, reliable approach to wiring door contacts:
- Use 22/2 stranded alarm wire for most installs
- Choose 22/4 if you want flexibility for future changes
- Stick with stranded, security-rated wire whenever possible
With the right wire, installation goes smoother, troubleshooting is easier, and your system is set up to last.
