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What is Grade 3?
Grade 3 is a European certification class for burglar alarm systems — designed for situations with elevated risk and professional intruders. On this page we explain what Grade 3 means, how it differs from Grade 2, and when it makes sense. Looking for the specific AJAX Superior product line? That is on AJAX Superior Grade 3.
Superior Grade 3 — wireless, tested to EN 50131 Grade 3.
EN 50131 in brief
EN 50131 is the European standard used by independent laboratories to assess how well an alarm system withstands sabotage, interference and targeted attacks. The standard defines four security grades. The higher the grade, the stricter the requirements.
Grade 1 & 2
Grade 1: minimal risk, inexperienced intruders. Grade 2: experienced intruders with basic tools. Most homes are well served by a properly designed Grade 2 system — for example AJAX with outdoor detection.
Grade 3
Protection against professionals with portable electronic equipment: masking, jamming, spoofing and tampering must be actively detected. Intended for banks, jewellers, museums — and increasingly for high-value homes.
Grade 4
The highest level, for extreme risk. Rarely relevant for private homes.
The weakest component counts
A system receives the grade of the weakest device in the configuration. One Grade 2 sensor in a Grade 3 setup? The entire system is rated Grade 2. More on certificates: licence & certification.
Grade 3 certificates come from independent European laboratories (EN 50131). Importantly, testing covers the full system under real-world conditions — not individual components on a bench. That is different from a sticker on a single device.
What does Grade 3 require technically?
Grade 3 goes beyond “something moved” or “a door opened”. The system must demonstrably resist targeted attacks:
- Anti-masking: the sensor detects when someone tries to cover, spray or manipulate the detection zone — even when the system is disarmed (relevant during longer vacancy).
- Tamper detection: dismantling or opening enclosures is reported within seconds.
- Jamming detection: signal interference is recognised — not ignored. With enhanced frequency hopping, hub and devices continuously switch between 16 frequencies in 4 European bands, as long as all devices are G3. See jamming & signal interference.
- G3 door and window sensors: built-in accelerometer (shock/tilt) and magnetometer against magnet spoofing — on top of standard opening detection.
- Spoofing protection: false signals or imitation of sensors must be blocked.
- Connection monitoring: loss of contact between hub and device within a short time (with AJAX: up to 36 seconds).
- Redundant communication: multiple connection paths where applicable (Ethernet, Wi-Fi, mobile).
Traditional Grade 3 systems were almost always wired: reliable, but expensive to install and invasive in the home. AJAX is the first manufacturer with a fully wireless Grade 3 ecosystem that has been independently tested.
Grade 2 vs. Grade 3
Grade 2 (standard AJAX)
- Suitable for most homes and holiday properties
- Jeweller protocol with jamming detection and strong encryption
- Combinable with outdoor detection and subscription-free ownership
- No alarms triggered by pets with professional placement
- Significantly lower investment than Grade 3
Grade 3 (Superior line)
- Stricter sabotage and masking requirements, laboratory tested
- Superior Jeweller protocol — on top of standard Jeweller
- Intended for villas, high contents value and elevated risk
- Only via accredited partners — no demo case at the door
- No pet immunity on G3 motion detectors: ultra-precise detection across the full area
Can be combined, with a caveat: Superior G3 devices and standard Jeweller sensors work in one system, but the system is then limited to Grade 2. With a Superior ReX G3, the G3 devices do keep enhanced frequency hopping (see below).
Who is Grade 3 relevant for?
- Owners of large villas or estates with valuable contents.
- Homes where insurer, adviser or own risk policy explicitly requires Grade 3.
- Situations with long-term vacancy and elevated risk of targeted burglary or sabotage.
- Owners who consciously want one of the highest recognised levels — not the cheapest package.
Not for everyone. For many homes in Spain, Grade 2 with professional outdoor detection is more than enough. Grade 3 is a conscious choice when your situation demands extra requirements. We advise honestly which level fits.
Wireless with wired-level reliability?
That is exactly what Grade 3 certification must demonstrate. With AJAX Superior that means: two-way communication, encryption, frequency hopping, authentication against spoofing and polling every 12 seconds. Connection loss is reported within 36 seconds. The Superior Hub G3 stays online via Ethernet, Wi-Fi and two SIM cards (2G/4G LTE) — relevant in Spain during power cuts or with an open meter cupboard on the street. The result is a wireless system with a reliability profile comparable to professional wired systems — without cables through walls and plasterwork.
The specific products, specifications and images of the Superior Jeweller G3 line are on our AJAX Superior Grade 3 page.
Superior Jeweller & frequency hopping
Grade 3 only stays Grade 3 if the whole system is G3
The Superior Hub G3 communicates with its devices via Superior Jeweller, the radio protocol for Grade 3 (EN 50131). It combines advanced encryption with enhanced frequency hopping: hub and devices switch together, following a defined pattern, between 16 frequencies in 4 frequency bands. If one channel is jammed, the message simply goes through another channel.
One Grade 2 device is enough to switch that off. According to Ajax Systems, enhanced frequency hopping only works if all wireless devices in the system support Superior Jeweller. Add even one device using the regular Jeweller protocol (such as a Grade 2 Baseline sensor) to the hub, and the whole system falls back to regular operation on 2 frequencies and is limited to Grade 2. Encryption does stay active.
Note: not every device with ‘Superior’ in its name supports Superior Jeweller. It concerns the G3 devices, plus a few Superior models with recent firmware (MotionCam AM, MotionCam HD and StreetSiren DoubleDeck). A regular ReX or ReX 2 range extender or a SpeakerPhone even disables enhanced frequency hopping in the entire system.
Grade 2 outdoor sensors in a Superior system? Then a Superior ReX G3
For outdoor detection (curtain and outdoor PIR) we often use Grade 2 sensors. If you want to combine them with a Superior system, we recommend an AJAX Superior ReX G3 Jeweller (range extender). Ajax describes exactly this solution: all devices without enhanced frequency hopping are connected to the ReX G3, so the G3 devices connected directly to the hub keep enhanced frequency hopping. This only works with a ReX G3, not with a regular ReX.
Superior Hub G3 with G3 devices onlyOptionally with a Superior ReX G3. Grade 3, with enhanced frequency hopping in the whole system.
G3 core on the hub, Grade 2 outdoor sensors via a Superior ReX G3Enhanced frequency hopping stays active for the G3 devices on the hub. The system as a whole is Grade 2.
Grade 2 device directly on the hub, or a regular ReX/ReX 2No enhanced frequency hopping in the system. The system is Grade 2.
To be fair: as soon as there are Grade 2 devices in the system, the installation as a whole is no longer a Grade 3 installation, not even with a ReX G3. What you do keep: the G3 core indoors communicates with enhanced frequency hopping against jamming, and the Grade 2 outdoor sensors still report interference via Jeweller. In the Ajax app you can see the ‘Frequency hopping’ status at the hub and the range extender. If it is not active, the app shows which device is the cause.
Source: Ajax Systems, user manuals Superior Hub G3 Jeweller and Superior ReX G3 Jeweller, and the support article on encryption and frequency hopping in Superior Jeweller (June 2026).
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Is Grade 3 needed for your home?
During a home visit we explain the difference between Grade 2 and Grade 3, and which setup makes sense for your situation. You meet the installers who will also install the system later.
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