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Can Burglars Disable Alarms By Cutting Cables?
Here’s how a burglar could disable your alarm and what you can do about it
How burglars disable alarms
A burglar can cut your power source or phone line to disable your wired alarm. And as cellular systems become more popular, thieves are finding ways to bypass those too.
In the past, most alarm systems connected to a landline. With the advent of the cell phone, home phones have gone out of vogue, and so have the burglar alarms that use them.
If you have a phone-line-based security system, a savvy burglar might cut the power, or telephone line, or both. They may cut the line, then enter the home and disable the alarm for good. They could even wait nearby for the alarm to use up all its backup battery before they loot the house.¹
We generally consider wireless, cellular alarms to be safer than landline-based ones. It’s much harder to disable a wireless alarm (like those from Frontpoint or SimpliSafe) than a wired one. But don’t get too comfy, because it’s still possible.
First off, data breaches are a threat to your wireless alarm systems. And we don’t mean that you just need to be careful if someone hacks your security provider’s databases. If you continuously repeat password-email combos, a data breach of another site could expose your alarm.
You’re also vulnerable to signal jamming. It isn’t easy to jam the signal and disrupt the alarm transmission, but it happens.²
How to protect yourself
After learning all this, you might feel pretty jaded about your home security system. Don’t worry; it can still protect you. You just have to take some steps to protect it from bad actors.
Landline-based system owners need to be cautious. Keep your alarm turned on so that if someone cuts the power, the backup battery kicks in. That may sound like a no-brainer, but you’d be surprised at how many people neglect to arm their security systems.
Battery backup kicks in when there’s a power outage. Cellular backup is for phone line outages. A wired security system is safest when it has both.
Check with your provider about cellular backup for your alarm. With cellular backup, your burglar alarm can still send a signal to the central monitoring station, even if someone cut the phone line.
Finally, when the alarm goes off, make sure someone responds right away. Usually, that’s the police, but if your system is self-monitored, you need a person with eyes on their notifications at all times. If someone shows up at home immediately after a breach, that’ll limit the burglar’s damage.
If your alarm company offers wired systems only, think twice before advertising with a sign in the yard or a sticker. You could be safest if you don’t advertise your system at all. The burglar will be unprepared to grapple with an alarm, so when it goes off, they may flee.
You can also try putting up another security system’s sticker/sign (or even a generic sticker/sign) if you prefer.
To prevent someone from hacking into your security account, use a unique password-email combination. Change that password often, and don’t share it with anyone who doesn’t absolutely need it.
Signal jamming is more complicated. It also requires special equipment, so it’s unlikely to happen to you. But just in case, ask your security company how it guards against jamming. Some systems, like SimpliSafe and Nest Secure, say they have preventive anti-jam features that alert the user.³
We also suggest getting some cameras. Even if your system is jammed, your cameras will still record footage that can help you catch the intruder.
Data effective 11/12/2020. Offers subject to change.
A burglar might disable your alarm by cutting wires or using other tricks. Still, there’s always something you can do to stay one step ahead of intruders. Keep your system on, make sure you have a backup, use a strong, unique password, and/or invest in some cameras.
Now that you know, here are your next steps.
If you have ADT or are thinking of getting a wired system, read our review.
If you don't have a burglar alarm but want one, here's a resource to check.
Burglar alarm FAQ
Still have questions? We’ll try to help you out.
Is a professionally monitored system safer?
Generally, yes, professional monitoring is safer than self-monitoring. With self-monitoring, the system’s not effective if you have even a minute of distraction. But when your system is monitored professionally, the alerts become the central monitoring station’s/police’s problem.
There are some downsides to professional monitoring, though. You’ll pay a monthly fee to your monitoring service. You might also pay your city for an alarm permit, depending on where you live. And if your system ever goes off for no reason, the city may fine you for a false alarm.
Will my smoke and carbon monoxide detectors work even if the power is down?
Any detector worth its salt should have a backup battery and work during a power outage. (Always check before buying one, of course, just to be sure.)
If you have a monitored smoke detector or carbon monoxide detector, it should still work locally when the phone line’s down (meaning that you should hear it in your home). But depending on how it’s set up, it may not be able to communicate with the fire department or other emergency responders. You might have to make those calls yourself.