Intruder alarm system grades explained
Most insurers specify a minimum alarm grade in your policy documents - check yours before installing or upgrading a system. Below, AMCO explains what grades 1-4 mean, what a true Grade 3 system actually requires, and how it's maintained.
What are the alarm grades?
BS EN 50131 defines four grades of intruder alarm system, based on the level of skill and equipment an intruder is assumed to have. The higher the grade, the more resilient the system needs to be.
| Grade | Risk level | Description |
|---|---|---|
| Grade 1 | Low risk | Intruders assumed to have limited knowledge of alarm systems and only basic tools. |
| Grade 2 | Low-medium risk | Some knowledge of alarm systems and a range of tools.Typically qualifies for police response |
| Grade 3 | Medium-high risk | Full knowledge of alarm systems and a comprehensive range of tools.Typically qualifies for police response |
| Grade 4 | High risk | Intruders with the ability to plan an intrusion in detail and access to a full range of equipment.Rarely used in practice |
Only Grade 2 and Grade 3 systems typically qualify for police response. Grade 4 is rarely used outside very high-risk commercial sites.
The single most important rule
A system's overall grade defaults to the lowest grade of any component fitted. One Grade 2 wireless sensor added to an otherwise Grade 3 system pulls the whole installation down to Grade 2 - so every part of the system needs to be specified and installed consistently.
Not sure what grade you need?
Check your insurance documentation, or ask AMCO to confirm the right grade for your property.
How to upgrade to Grade 3
A true Grade 3 system isn't just a different setting on the panel - every component needs to be rated and installed to Grade 3 requirements.
Grade 3 alarm panel
A metal enclosure with back-tamper protection - not the plastic casing found on most Grade 2 panels.
Grade 3 sensors
Wired, with both front and back tamper protection plus anti-masking detection, so a sensor can't be blocked or covered without triggering an alert.
No wireless equipment
A true Grade 3 system is wired throughout. Most wireless sensors on the market are only Grade 2 rated.
Grade 3 external bell box
Rated to Grade 3, with multiple tamper switches to detect any attempt to remove or disable it.
Correctly rated signalling
Monitoring/signalling equipment rated to DP3 or DP4, matching the rest of the system.
British Standards referenced
Alarm grading draws on several British and European standards - here's what each one actually covers.
BS 4737
The former UK standard, withdrawn in 2004.
PD 6662:2017
The UK's adoption of the current European standards.
BS 9263
System maintenance requirements.
BS 8243:2010
Confirmed-activation systems, used for police response.
BS EN 50131
General intruder alarm system requirements.
BS EN 50136
Alarm signalling and transmission systems.
SS 2004
The SSAIB code of practice for temporary systems.
Alarm signalling & monitoring types
The signalling path is how your alarm reports an activation to a monitoring centre. Its grade needs to match the rest of your system.
Redcare (BT)
A legacy single-path signalling service that ran over the phone line. BT has now closed this service, so customers previously on Redcare have moved to DualCom or LiveTalk.
DualCom (CSL)
A dual-path signalling device using both the phone line and the mobile network as backup. Available at Grade 2, 3 or 4, depending on how frequently it polls to confirm it's still working.
LiveTalk (AMCO)
AMCO's own audio-confirmation monitoring technology. An operator listens and talks into the property to confirm a genuine break-in, which speeds up the police response.
More about LiveTalkAMCO's monitored alarms are built around LiveTalk - read more about how LiveTalk works or see our full guide to monitored alarms.
Maintenance & fault-reporting requirements
Higher grades require more frequent maintenance visits, and faster reporting of any fault on the signalling path.
Maintenance visits required
| Grade | Requirement |
|---|---|
| Grade 2 | 1 annual site visit |
| Grade 2 & 3 | 2 annual visits, or 1 site visit plus 1 remote check |
| Grade 4 | 2 annual site visits |
Time to report a fault
| Grade | Time to report |
|---|---|
| Grade 2 | 24 hours |
| Grade 3 | 1 hour |
| Grade 4 | 3 minutes |
A Grade 3 specialist installer
AMCO has fitted and maintained graded intruder alarm systems for over 25 years, from standard Grade 2 domestic installs to full Grade 3 systems for high-risk commercial sites. Our engineers know exactly which panels, sensors and signalling equipment keep a system's grade consistent throughout.
Read more about our Texecom installation expertise or see our business security services.
Why customers choose AMCO
- Grade 3 specialist installer, NSI & SSAIB approved
- 25+ years fitting and maintaining graded alarm systems
- UK-wide coverage, from single sites to multi-site estates
Need a Grade 3 system surveyed?
AMCO can assess your current setup and confirm exactly what's needed to reach - and keep - Grade 3.
What insurers expect from a graded system
Common questions about how alarm grades, approval bodies and keyholder protocols affect your insurance cover.
It depends on the property and how the system is used. As a rough guide, audible-only systems are usually rated Grade 2E, monitored domestic systems are typically Grade 2, and monitored commercial systems are usually expected to be Grade 3.
Your policy documents will state the exact grade required - check these before installing or upgrading a system, or see our insurance specifications page for AMCO's own compliance detail.
Free, no-obligation
Ready to check your alarm's grade?
Whether you need a standard Grade 2 install or a full Grade 3 specification, see our insurance specifications or get in touch and we'll advise on the right system for your policy.
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