Most alarms make noise. The good ones make things happen — a confirmed signal, a monitoring centre, a police dispatch. As an NSI Gold installer, Gemini AMPM fits intruder alarms the police will actually attend, graded to BS EN 50131 and signalled to an alarm receiving centre around the clock.
BS EN 50131 grades intruder alarms by the adversary they must resist. Grade 2 assumes an opportunist with basic tools — right for most homes and business premises. Grade 3 assumes a prepared intruder who understands alarms and will attack the system itself; insurers demand it for higher-value stock, safes and higher-risk trades. PD 6662 is the scheme that pulls those European standards into a single UK rulebook, and it is what your insurance wording actually points at.
We risk-assess first, then grade the design to match your insurer’s requirement rather than guessing. For occupied and heritage buildings we install Ajax Systems wireless devices — certificated, supervised and jamming-detected — so a properly graded system goes in without chasing cable through every wall in the building.
Police forces do not attend unconfirmed automatic alarms. To earn a response, a system needs a unique reference number — a URN — issued by the local force, and URNs are only granted to systems installed and maintained by inspectorate-approved firms. Our NSI Gold approval is the ticket in. We handle the application, the signalling and the paperwork.
Confirmation is the other half. Under BS 8243, the alarm receiving centre waits for two independent detections — two detectors, or a detector plus a door contact — before declaring a confirmed event and passing it to police. That sequential confirmation is what separates a dispatched patrol from a logged note. False alarms are managed just as seriously, because a URN that loses its response through sloppy maintenance is worth nothing.
A URN — unique reference number — is issued by your local police force and registers your alarm for police response. Forces only grant them to systems installed and maintained by firms certificated by an approved inspectorate such as NSI, signalling to an approved alarm receiving centre. Without one, an automatic intruder alarm gets no guaranteed attendance, however loud it is. We apply for the URN, maintain the system and keep the response level intact.
Yes, provided it is certificated to the right grade and installed under PD 6662 by an approved company. Ajax Systems wireless devices carry BS EN 50131 certification with supervised radio links, tamper protection and jamming detection, which is what underwriters actually care about. What insurers reject is uncertificated DIY kit with no maintenance behind it. We confirm the required grade against your policy wording before design, and certificate the installation on completion.
Under national police policy, three false calls in a rolling twelve months and your URN response is withdrawn — the alarm still sounds, but nobody is coming. BS 8243 sequential confirmation filters most nuisance triggers before they ever reach the police, and disciplined maintenance deals with the rest: failing detectors, drifting sensors, poorly trained users. If your current system is on its final strike, we can usually rescue the URN rather than restart the application.
A named engineer, not a call centre, comes back within 24 hours. Tell us the building and what you’re dealing with, and we’ll scope it properly.