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How Do Burglars Defeat Alarm Systems?

Having an alarm system is an effective way to keep you and your property protected against burglaries, intrusions, and break-ins.

They consist of a series of electrical components that work using sensors and contacts that are connected to a property to detect movement, opening or closing of doors, and unusual sounds.

They are connected to a loud siren or alarm that gets triggered every time the system detects something unusual and out of the ordinary, such as someone opening the door when it is least expected, for instance during the night or when none of the inhabitants are expected to be on the property.

What this does is not only deter criminals from targeting your property but also scare them away if they attempt to do so through the blaring sirens often accompanied by flashing lights.

While these alarm systems are a pretty solid solution for keeping such threats at bay, if you are serious about your property’s security, you must know that it is not enough to just install an alarm system and forget about it.

You must understand that while security systems are becoming smarter and more technologically advanced, so are criminals. They come up with ways to bypass them and find ways to break into your property without getting noticed.

Knowing how a burglar’s mind works and how they defeat alarm systems will help you invest in the right security measures to prevent it from happening.

Read on to find out about the different types of alarm systems, how they work, how burglars defeat them, and the steps you can take to foil their plans:


Installing a high-quality alarm system on your property is one of the most effective and reliable ways to protect it against threats such as burglaries, theft, and intrusions.

It doesn’t matter how big or small your home or office is, what matters is that all the doors, windows, and other entry points are secured using sensors and alarm systems.

According to statistics, properties with an effective security system in place are less likely to be broken into as compared to ones with no proper protection.

There are several types of alarm systems that you can install on your property, all of which include a few basic components such as a control panel, one or more sensors, and sirens and alerts.

Although the purpose of all alarm systems is to detect intrusions in one way or the other, they differ in the way they operate and the criteria that triggers them.

Some of the most popular types of alarm systems include using the following sensors:

  • Motion sensors: installed both inside and outside of a property, these sensors work by identifying movement and communicating with the control panel to trigger the alarm every time they do.

Also known as PIR sensors, they create an invisible zone that cannot be breached without triggering an alarm and are typically used to protect areas containing valuables and where unauthorised access needs to be controlled.

  • Door and window sensors: triggered by detecting unauthorised access by the opening of doors and windows, these sensors are made up of two parts, one of which is installed on the door or window, and the other one on the door frame or window sill.

When the doors or windows are closed, the two parts of the sensor are joined together creating a circuit. When they are opened, the circuit breaks and the control panel is notified, which sees this as a security breach and triggers a loud siren or alarm.

  • Glass-break detectors: designed to trigger an alarm when they detect the unique audio frequency of a glass breaking or the vibrations that occur.

Extremely useful in situations where intruders gain unauthorised access into your property by smashing a window or glass door, these detectors are installed in high-risk areas where you think someone might easily break-in.


All alarm systems come in two variants: wired and wireless.

Wired systems are the traditional ones that have been used ever since alarm systems came into existence. They use wires running in between all the sensors, control panels, and other components for it to work.

They are typically more complex to install and require professional installation services to get it right. They usually utilise a landline phone line to connect the system and to send alerts to the property owners in case of an alarm trigger. They may also be hardwired directly into the property’s electrical system.

Wireless alarm systems, on the other hand, use battery-powered sensors that communicate with the control panel via Wi-Fi and radio signals.

Not only do these systems look nicer and provide a cleaner look, but they are also less complicated to install as compared to their wired counterparts. Also, adding extra sensors and relocating the system is much easier.

The most common wireless alarm systems these days use your property’s internet connection to connect the various components of the system and to allow you to monitor it remotely.

When it comes to the most secure wireless alarm system, many property owners opt for systems that use cellular networks to communicate. They are not dependent on your property’s electrical system or internet signal and rely instead on the same technology used by smartphones to communicate.


Now that you know all about the different types of alarm systems and how they work, here are a few ways that burglars defeat alarm systems and are successful at breaking into your property without raising any alarms:

Power outages

Power outages are one of the most common ways to bypass an alarm system, especially one that is wired and relies on the property’s electrical system to operate.

Although most alarms come with a backup battery option, they have certain limitations that burglars tend to take advantage of.

For starters, these backup batteries have a limited life and generally last only 24 to 48 hours. Therefore, during an extended power outage, a burglar can easily break into a property since the alarm system would be disabled.

They might not even wait for a power outage and cut the electricity supply to your property to put your security in a vulnerable state.

Many property owners fail to replace their old backup batteries with new, longer-lasting ones, leaving them without any form of security within only a few hours of an outage.

Testing your batteries regularly and stocking up on a few extra backup ones will ensure that your alarm system continues to work despite any power outages.

Disarming alarm with code

An alarm system typically features a keypad or touchpad for easy management and interaction, where a code is entered to arm or disarm the system. It can also work using voice commands as well as remote controls or key fobs.

In the case of a code, many property owners tend to give the same code to anyone who may need to disarm the system, such as their domestic help, employees, or service providers.

Not only does this make it impossible to track who disarmed the system but it also increases the chances of the code falling into the wrong hands.

The longer you use the same code for the system and the more people you hand it out to puts the system and your security at risk. You never know when it might reach a potential criminal who would then use it to target you and your property.

You must hand out different alarm codes only to a few trusted individuals so that you can track who disarmed the alarm, in addition to being able to delete old codes that you no longer need, denying access to any individuals who may have stumbled upon them.

Searching for weak spots

Though alarm systems are one of the most effective deterrents against burglaries and intrusions, improper installation and a lack of maintenance can lead to weak spots that criminals may take advantage of.

Correct placement of the sensors is key when it comes to alarm systems. If the sensors are placed in areas that are not high-risk, while the actual high-risk areas are left unattended, it is equal to not having an alarm system on your property at all.

Many property owners opt for a minimal amount of security to keep costs low, but that is not recommended. What you must do is use the system smartly so that you reap all its benefits along with staying on budget.

When it comes to homes, the master bedroom is the prime target since that is where people usually keep their cash, jewellery, and other valuable items.

Therefore, if you place sensors on the main door and windows while leaving the second-floor master bedroom window in a vulnerable state without contact sensors, you can expect burglars to take advantage of this situation and break in through it.

Cutting off the alarm’s communication

Many alarm systems rely on a property’s landline connection for communication between the alarm and the property owners or emergency responders.

When burglars think that a property has an alarm system in place, they are likely to cut off the phone lines in an attempt to break off any connection for alerts.

This way, even if the alarm is triggered and it creates a blaring siren response when detecting an intrusion, the system will no longer be able to dial for help, which can be extremely dangerous if the property is empty or situated in an isolated area.

For this reason, many people are shifting from landline-based monitoring to cellular dialling and Wi-Fi systems.

A cellular dialler uses radio signals to communicate with the property owners and the monitoring station in case of professional alarm monitoring services and activates a police response regardless of whether your landline is working or not.

Not only is this more secure and fool-proof but it also allows you to control and monitor the alarm system with your smartphone and receive notifications about changes in the alarm system’s status including activations caused by break-ins and intrusions.

Staying after activating the alarm

The time it takes for the police to respond to an alarm activation varies greatly depending on the area that your property is in.

This can be because your property is in a secluded location or that you have a record of multiple false alarm activations in the past.

Most burglars do their proper research before targeting a property and have a good idea about the average police response time.

Therefore, even if your alarm system detects unauthorised entry and sounds a loud siren, some burglars may stick around even after that for a while and get their hands on whatever they can.

A few ways in which you can help expedite a police response to your house is to ensure your alarm system is properly maintained and in top shape to avoid any false alarms.

Additionally, you may opt for interactive cellular monitoring where you will receive instant notifications of an intrusion, allowing you to call the authorities yourself right away.


Burglars are able to defeat your alarm system because, let’s be honest, they are given the opportunity to do so. By not being extra careful and thorough when it comes to security, you put yourself and your property at risk and allow criminals to take advantage of weaknesses in your security system.

There are a few steps you can take to help increase your property’s security and make your home or office a less likely target for criminals.

Use good quality locks

The first step towards making your property safer and more secure is to always lock the doors and windows, and not just when you are out but also when you are in the building.

You must inspect all your exterior doors and windows to check for vulnerabilities and reinforce them using good quality locking mechanisms and use strong and sturdy materials such as wood, composite, and uPVC for the door and window frames.

Some of the best front door locks include deadbolts, mortice locks, rim locks, lever locks, and anti-snap Euro cylinder locks.

In addition to keeping your doors and windows locked, you must also lock up your electrical panels and distribution boards to prevent criminals from gaining access to them to disconnect your power supply.

Keep your property well-lit

Burglars prefer targeting properties that are empty since it makes it easier for them to break in unnoticed, which is why so many cases are reported during the holidays and when people are travelling.

Lighting up the front and back of your property will not only make burglars wary about targeting it but also eliminate any hiding places and blind spots that could potentially be used by them.

You may use motion-activated lights that turn on as soon as someone steps foot under them and put outdoor lights on a timer that can be controlled remotely via a mobile phone.

Install CCTV cameras

CCTV (Closed-Circuit Television) cameras are one of the most effective security systems available in the market today that not only deter criminals but also help identify them.

Placement of the cameras is key to their effectiveness, which is why careful thought must be given to where and how they must be placed and what exactly they must record.


At Calder Security, we provide a comprehensive range of security solutions that include not just professional installation but also monitoring, maintenance, and repair services.

We understand that everyone has a set budget and unique requirements and, for that, we have tailored solutions for all kinds of individuals and property owners.

We are members of the Master Locksmith Association (MLA), approved members of the Security Systems and Alarms Inspection Board (SSAIB), and also conform to all the relevant British and EU Standards.

We follow all the best practices in the industry and install only high-quality, state-of-the-art security systems.

We offer various levels of monitoring via a 24-hour monitoring centre using Dualcom and BT Redcare signalling, which is the most secure alarm monitoring system and the largest supplier of intelligent alarm signalling services in the UK.

We understand the importance of having to regularly maintain security systems since the inability to do so might result in serious faults and consequent vulnerabilities in your property’s security.

We provide professional maintenance checks and reminders for when the checks are due to help you stay compliant with the law and work fast to restore your security systems to excellent condition.

We offer a 24-hour call-out service for customers and can also repair systems not installed by us. Our engineers are highly skilled and can restore faulty systems to full working order in one visit.

Contact us here or call us on 0800 612 9799 to talk to our experts right away!

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