Intruder Alarms in the UK: Wired Alarms, Wireless Alarms, Alarm Grading Systems and Why It All Actually Matters.

Intruder alarms are one of the most effective ways to protect homes, businesses, farms, schools and commercial sites across the UK. Yet we see the same pattern again and again:

• Alarms installed years ago, but never actually used

• Systems that don’t meet current insurance expectations

• Cheap DIY kits that offer false reassurance

• Owners confused by “grades”, “monitoring” and “signalling”

At Phantom Communications Ltd, we design, install and upgrade intruder alarms that are built around your risk, your property, and your insurance requirements. This guide is designed to demystify the world of intruder alarms so you can make informed decisions with confidence.

⚠️ Before you install or upgrade an intruder alarm, always check your insurance documentation or speak to your insurer. They may require a specific alarm grade and signalling type for full cover.

Intruder alarms offer early warning and act as a visible deterrence

Why Intruder Alarms Still Matter

With CCTV, smart lighting and other tech, some people assume alarms are old-fashioned. They’re not. A well-designed, properly used intruder alarm still delivers three core benefits that nothing else can fully replace:

1. Deterrence

A visible, professional alarm system sends a clear message:

“This property is protected and monitored.”

Bell boxes, warning decals and external sirens make opportunist intruders think twice. Criminals typically choose the easiest target – a working alarm moves you off that list.

2. Early Detection

A good system doesn’t just detect someone in the building – it often detects them trying to get in:

• Door contacts

• Window shock sensors

• External PIRs and beams

• Roller shutter and roof detectors

The earlier you know something is happening, the less time an intruder has to cause damage.

3. Response

Whether through a loud external siren, keyholder attendance, or full monitored police response, an intruder alarm links suspicious activity to actual action – not just a recording to look at afterwards.

The Hidden Problem: Alarms That Aren’t Actually Used

One of the biggest issues we encounter during surveys is simple:

“We’ve got an alarm… but we don’t use it.”

The reasons are familiar:

• The system is very old and unreliable

• There have been too many false alarms

• Nobody remembers the codes

• The external sounder doesn’t work

• The panel or keypad is confusing

• The installer disappeared years ago

• The system was never properly explained

The result?

• No deterrent – criminals often recognise an old dead box

• No early warning – if someone breaks in, nothing triggers

• Potential insurance issues if your policy assumes a working alarm

• False sense of security – the alarm is “there”, but useless

In many cases, it’s more effective (and often cheaper in the long run) to replace the system with a modern, user-friendly, graded alarm than to keep fighting with something that nobody trusts.

Alarm Standards & Grades – The Framework Behind a “Proper” System

Intruder alarms in the UK are designed to British and European standards, mainly:

• PD 6662:2017 – UK scheme for adopting European intruder alarm standards

• BS EN 50131 – General requirements (including the grading system)

• BS EN 50136 – Alarm transmission (signalling) to alarm receiving centres

• BS 8243 – Systems designed for “confirmed activation” (police response)

• BS 9263 – Maintenance of intruder alarm systems

These standards define four alarm grades based on the expected type of intruder, their skill level and the tools they might use:

• Grade 1 – Very low risk

• Grade 2 – Low to medium risk (most homes / small sites)

• Grade 3 – Medium to high risk (most commercial & higher-risk sites)

• Grade 4 – Very high risk (banks, high-value jewellers, sensitive sites)

In practice, almost all real systems should be designed to Grade 2 or Grade 3. Grade 4 is rare outside very specialised environments.

How Grading Actually Works (and Why the Lowest Grade Wins)

Every major component in a professionally designed alarm – control panel, detectors, power supplies, sounders, signalling units – is certified to a grade (G1, G2, G3 or G4).

Two core rules:

1. The system can only be graded as high as its lowest-graded component.

   • If you have all Grade 3 devices but one Grade 2 detector, the system is Grade 2 at best.

2. You can mix higher-grade devices in lower-grade systems, but not the other way round.

   • A Grade 3 power supply in an otherwise Grade 2 system is fine – the system is still Grade 2.

   • You can’t claim Grade 3 if any part of the intruder detection is Grade 2.

You can have certain functions (like a hold-up/panic system) at a higher grade than the intruder system, but only if everything associated with that function – power, signalling, detectors, warning devices – is at the same or higher grade.

Grade 2 vs Grade 3 vs Grade 4 – In Practical Terms

Beyond more detectors and larger event memories, there are important technical differences:

Grade 2 – Low to Medium Risk

Typical for most UK homes, small offices, and lower-risk premises.

• Grade 2 certified control panel and peripherals

• Robust tamper protection on covers and wiring

• Standard PIRs, door contacts, shock sensors etc.

• External sounder with tamper and backup battery

• Backup battery in the main panel

Grade 3 – Medium to High Risk

Typically used for shops, warehouses, farms, schools, industrial units and higher-value homes.

• Higher resilience detectors, often dual-tech

• Anti-masking: movement sensors must detect attempts to cover or spray them

• Stronger tamper monitoring and fault supervision

• More comprehensive perimeter detection

• Enhanced signalling, usually dual-path monitored

• Often tied to police response via an Alarm Receiving Centre (ARC)

Grade 4 – Very High Risk

For banks, high-value jewellers, sensitive or critical sites.

• Movement sensors capable of detecting range reduction – attempts to block their field of view

• Multiple layers of redundancy and protection

• Stringent signalling and monitoring requirements

  
  

For almost all homes and most businesses, a correctly designed Grade 2 or Grade 3 system is the right and realistic choice.

Wired, Wireless & Hybrid Systems – And What They Can Be Graded To

A lot of people still think “wireless alarms are just toys”. That might be true for cheap DIY kits – but professional wireless alarms are very different.

Wired Systems

• All devices cabled back to the panel

• No detector batteries to change

• Very robust, ideal for new builds or refurbishments

Grading: Can be designed to Grade 2, 3 or 4, depending on the equipment and design.

Wireless Systems (Professional)

Modern wireless alarms use:

• Encrypted radio communication

• Supervision (devices regularly check in with the panel)

• Jamming detection

• Battery level monitoring

They are certified to EN standards just like wired devices.

Grading:

• Most professional wireless systems are certified up to Grade 2

• Perfectly suitable for domestic and light commercial properties when correctly specified.

Hybrid Systems

Hybrid panels support both wired and wireless zones:

• Reuse existing good-quality wiring (entry doors, main PIRs, etc.)

• Add wireless devices where cabling would be disruptive or costly – outbuildings, finished areas, high ceilings

Grading:

• Commonly used to achieve Grade 2 solutions, especially in upgrades and larger sites.

At Phantom Communications Ltd, we often recommend hybrid systems to get the best balance between reliability, flexibility and cost while still meeting the required grade.

Monitored vs Unmonitored (Bells-Only) Systems

Bells-Only (Unmonitored)

When the alarm is triggered:

• Internal sounder activates

• External siren/bell box sounds and strobes

• On some modern systems, you may get an app notification

Pros:

• No ongoing monitoring costs

• Strong local deterrent in built-up areas

• Suitable for lower-risk properties

Cons:

• No guaranteed response

• Sirens are often ignored

• Not ideal for remote or rural sites

• Many insurers prefer monitoring for higher risks

Monitored Systems

When the alarm triggers:

• A signal is sent to an Alarm Receiving Centre (ARC)

• The ARC follows a response protocol – calling keyholders and/or requesting police attendance where applicable

• For “confirmed alarms”, multiple signals or detectors are used to reduce false alarms

Monitored systems use Alarm Transmission Systems (ATS) defined by BS EN 50136, which can be:

• Single-path: one communication route (e.g. IP, GSM)

• Dual-path: two independent routes (e.g. IP + 4G), providing resilience if one fails

Pros:

• 24/7 professional monitoring

• Structured escalation and response

• Meets insurer expectations for higher risk properties

• Essential for many commercial risks and remote sites

Cons:

• Monitoring and service fees

• Must be correctly specified and maintained

Most commercial and many higher-risk domestic properties will benefit from – or be required by insurers to have – monitored, graded systems.

Alarm Signalling (ATS) & Polling – How Your Alarm Talks to the ARC

Alarm signalling is how your intruder alarm communicates with the ARC. This is classified under Alarm Transmission Systems (ATS) in EN 50136.

Key considerations:

• How many paths (routes) are used – single or dual

• What technology is used – PSTN (legacy), IP, GSM/4G, etc.

• How frequently the ARC checks that the system is still “alive” (polling)

• How quickly a failure on one or both paths must be reported

Path Failure Reporting (Typical Guide)

When both paths fail at the same time (worst case scenario), typical expectations are:

• Grade 2: ARC notified within 24–25 hours

• Grade 3: ARC notified within 1–5 hours (depending on ATS category)

• Grade 4: ARC notified within around 3 minutes

The higher the grade, the quicker the ARC must be made aware of signalling problems.

Many modern dual-path units “poll” both paths frequently. If they lose one path, they still signal on the other; if they lose both, they trigger a fault alarm at the ARC within the allowed timeframe.

Internal Detection – The Devices Doing the Work

Inside the building, a mix of detectors is used to create layers of protection.

PIR (Passive Infrared) Sensors

Detect movement based on changes in heat. Ideal for:

• Living rooms

• Offices

• Hallways and landings

• Open-plan areas

Available in standard and pet-friendly versions.

Dual-Tech Detectors

Combine PIR with microwave detection:

• Greatly reduce false alarms in draughty or harsh environments

• Commonly used in warehouses, workshops, and higher-grade (Grade 3) systems

Door Contacts

Small magnetic switches that trigger when the door opens:

• Used on main entry doors, fire exits, roller doors, etc.

• Provide early perimeter detection

  

Shock / Vibration Sensors

Detect knocks, hits and drilling attempts:

• Installed on windows, doors, shutters, safes, roof hatches

• Often trigger before an intruder gains entry

Panic / Hold-Up Devices

Fixed or portable buttons:

• Used in shops, offices, schools and lone-worker areas

• Can generate a faster, specific response when monitored

Keypads & Readers

Modern user interfaces can include:

• Backlit keypads

• Touchscreens

• Proximity tags/fobs/cards

• Multiple user codes and logs

These make the system easier to use daily – which is critical for compliance and safety.

External Detection & Devices

External Sounder / Bell Box

The most visible part of your alarm:

• Should be mounted high and visible

• Include a strobe, sounder and its own backup battery

• Have tamper detection

• Be in good cosmetic condition – a faded or silent box screams “neglected system”

External PIRs & Dual-Techs

Provide early warning around:

• Yards

• Car parks

• Farmyards

• Compounds

• Loading bays

These need to be professional-grade to handle weather, animals and environmental movement.

Perimeter Beams

Infrared or microwave beams used to protect:

• Fence lines

• Gate lines

• Long driveways

• Open yards

Excellent for large outdoor spaces, storage yards, and remote business premises.

Maintenance & Grading – Keeping Your System “In Grade”

To remain compliant (especially for police response and insurance), graded systems must be maintained:

Typical maintenance patterns:

• Grade 2: at least 1 site visit per year

• Grade 2 & 3:

  • 2 service events per year, either:

    • 2 site visits, or

    • 1 site visit + 1 remote check

• Grade 4: generally 2 site visits per year

Maintenance includes:

• Full system testing

• Log and event review

• Battery tests and replacement where required

• Signalling checks and test calls to the ARC

• Confirming no changes to building layout have weakened coverage

At Phantom Communications Ltd, we treat maintenance as part of the core security solution — not an optional extra.

Insurers: What They Usually Expect

While every insurer is different, many follow similar guidance. Common themes include:

• Use of NSI or SSAIB-approved alarm companies or systems designed to those standards

• A system grade matched to the risk, e.g.:

  • Audible-only: Grade 2E

  • Monitored domestic: typically Grade 2

  • Monitored commercial: typically Grade 3

• Adequate detection in all “at-risk” areas – not just one PIR in a hallway

• Reliable response to alarm activations, usually via an ARC and keyholders

• An ATS (signalling) that:

  • Is frequently checked (polling)

  • Reports faults promptly (e.g. DP2/DP3 categories)

  • Uses dual-path for higher-value or higher-risk sites

Keyholder expectations:

• Keyholders should be trustworthy, trained and fully briefed

• Ideal to have at least two people attend an activation (for safety)

• Procedures should be in place – not just “whoever is free goes and has a look”

Where a third-party keyholding company is used, insurers typically prefer:

• SIA-licensed staff

• Operation in line with BS 7984 (Keyholding & Response)

• Suitable insurance

• Independent audits / NSI or SSAIB listing

Is It Time to Replace or Upgrade Your Intruder Alarm?

Good questions to ask yourself:

• Do you know what grade your current system is?

• Do you know how it signals an alarm (if at all)?

• Has it been serviced in the last 12 months?

• Is it older than 10 years?

• Is it actually armed every day?

• Does it still meet your insurance requirements?

If the answer is “no”, “I don’t know” or “we never use it”, it’s worth speaking to a professional.

How Phantom Communications Ltd Can Help

We provide:

• Free, no-obligation intruder alarm surveys

• Honest review of your existing system and its real-world grade

• Design of wired, wireless or hybrid systems to Grade 2 or Grade 3

• Bells-only or monitored solutions with appropriate signalling

• Annual maintenance and support packages

• Integration with CCTV and other security layers where required

Our goal is simple:

To give you an alarm system you understand, trust, and actually use.