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Intruder alarm installation

Commercial Intruder Alarm Installers: Graded Systems to BS EN 50131 and PD 6662

Risk-assessed, graded intruder alarm design and installation for commercial and industrial premises across Yorkshire, Lincolnshire and the Humber.

SPS Technical is a commercial intruder alarm installer designing and installing graded systems for commercial and industrial premises across Yorkshire, Lincolnshire and the Humber. Every installation begins with a risk assessment that determines the correct grade under EN50131 and PD6662 — from Grade 2 for low-to-medium risk premises up to Grade 3 for higher-value commercial sites requiring confirmed alarm response and ARC monitoring. As an SSAIB certified installer, systems we install to the required standard can qualify for a police Unique Reference Number (URN) for police response.

Grading explained

Under EN50131 and PD6662, every intruder alarm must be graded to reflect the level of risk at the premises. The grade determines detector specification, panel capability, signalling requirements and ARC monitoring standards. Getting the grade wrong means either under-protecting your premises or paying for unnecessary capability — and insurers and police check compliance. SPS Technical carries out a full risk assessment before specifying any system.

Commercial intruder alarm systems

SSAIB intruder alarm installation — choosing the right EN50131 grade

Under EN50131 and PD6662, every intruder alarm must be graded to reflect the level of risk at the premises. The grade determines detector specification, panel capability, signalling requirements and ARC monitoring standards.

G1

Grade 1

Low risk

Premises unlikely to attract targeted intruders. Opportunistic threat only. Rarely specified for standalone commercial premises.

Low-risk internal areas and storage spaces
G2

Grade 2

Low to medium risk

Minimum standard accepted by most insurers for commercial premises. Assumes opportunistic intruder with basic tools.

Offices, small retail, light commercial
G3

Grade 3

Medium to high risk

Standard for most commercial premises with valuable stock or assets. Often required by insurers for higher-risk premises.

Required for police response — most commercial sites
G4

Grade 4

High risk

Very high value premises. Assumes planned attack and specialist knowledge. Intruder may attempt to tamper with the system itself.

Cash handling, data centres, high-security sites
Grade 3 is common for commercial premises with valuable stock or a higher risk. Your insurer may set the grade. SPS Technical carries out a full risk assessment before specifying any system.

Detection technology

Intruder Detection Technology

Modern commercial intruder alarm systems use a combination of detection technologies to minimise false alarms while maintaining reliable detection. PIR detectors are the standard for most internal spaces. Dual-technology detectors combine PIR and microwave to reduce nuisance alarms in challenging environments. Door contacts, shock detectors and vibration detectors provide perimeter coverage. Grade 3 systems require detectors with anti-masking capability to prevent deliberate interference.

PIR detectors

Passive infrared movement detection, the standard for most commercial spaces

Dual-technology detectors

PIR plus microwave, reducing false alarms in challenging environments

Door and window contacts

Perimeter detection on all access points

Shock detectors

Glass break and impact detection for perimeter security

Vibration detectors

Structural attack detection for high-risk premises

CCTV-verified detection

Visual confirmation reducing false alarm callouts

Alarm Signalling and ARC Monitoring

Grade 3 systems require dual-path signalling to an Alarm Receiving Centre — two independent transmission routes so that a single path failure cannot prevent an alarm reaching the monitoring centre. SPS Technical installs IP and 4G dual-path signalling to EN50136 on all new Grade 3 systems. With the PSTN analogue telephone network being switched off across the UK, all new installations use IP or 4G signalling as standard.

Dual-path signalling

Grade 3 requires IP/4G dual-path

Grade 3 systems require dual-path signalling to an ARC — two independent transmission routes so that a single path failure doesn't prevent an alarm reaching the monitoring centre. SPS Technical installs IP and 4G dual-path signalling to EN50136, maintaining ARC connection and police response eligibility even if one path is disrupted. With the PSTN switch-off underway, all new installations use IP/4G signalling as standard.

Our process

How a Graded Intruder Alarm Installation Works

Every SPS Technical intruder alarm installation follows a structured process from risk assessment through to SSAIB certification. No system is commissioned without full zone testing, entry/exit timing verification and ARC connection confirmation.

1

Risk assessment

Premises, contents, occupancy and threat level assessed

2

System design

Grade determined, detector placement and panel specified to EN50131/PD6662

3

Installation

Detectors, panel, sounders and signalling equipment installed

4

Commissioning

All zones tested, entry/exit timing configured, ARC connection established

5

Certification

SSAIB certificate of compliance issued, police URN applied for

1

Risk assessment

Premises, contents, occupancy and threat level assessed

2

System design

Grade determined, detector placement and panel specified to EN50131/PD6662

3

Installation

Detectors, panel, sounders and signalling equipment installed

4

Commissioning

All zones tested, entry/exit timing configured, ARC connection established

5

Certification

SSAIB certificate of compliance issued, police URN applied for

Standards that apply

The standards behind intruder alarm installation

The British Standards and laws we work to, in plain English. Each one links to a summary page with the current edition and the official source.

Got a question about intruder alarm installation?

Ask the Standards Library. Answers come only from our library and quote their sources.

Full resource library →

Try one of these:

Answers come only from our standards library and quote their sources. They are general guidance, not advice for a specific building, and are produced automatically, so check the source before relying on them. Please don't include names or personal details in your question.

Editions checked 12 October 2026 by the SPS Technical team.

FAQs

Installation questions

Most commercial premises need Grade 2 or Grade 3. Grade 3 is usual where there is higher-value stock or a higher risk of break-in, and your insurer may set the grade. We agree it with you at survey.

Yes. We inspect it, fix anything that doesn't meet the standard and, where it qualifies, transfer the police URN to us.

If your alarm signals over an analogue phone line, yes. Analogue lines are being switched off, so the signalling needs moving to a digital or dual-path IP service. Our free PSTN Checker tells you where you stand.

Book an intruder alarm site survey

Risk assessment, system design and an itemised quote, with no obligation.

Accreditations

Why trust SPS Technical

Independently certified, working to British Standards. Check every accreditation on the official register.

SSAIB

Registration HUMB018

Intruder alarms to PD 6662, CCTV to SSAIB Code of Practice SS2003, access control to SS2002, and fire alarm systems

Verify at ssaib.org

BAFE SP203-1

Certificate 104302 · Organisation ID 303286

Fire alarm design, installation, commissioning and maintenance to BS 5839-1

Verify at bafe.org.uk

ISO 9001 and ISO 14001

1208-QMS-001 · 1208-EMS-001

Quality and environmental management, certified by Alcumus ISOQAR. ISO 9001 held since 1997

Safety and procurement

CHAS-0004703 · Constructionline 92018 · SafeContractor PE5040

SSIP health and safety approval, procurement registration and Paxton Gold Installer status

Police-response intruder alarms

For intruder alarms, SPS Technical is an approved installer of police-response systems with the following forces, so your intruder alarm can be issued a police Unique Reference Number (URN) under the NPCC Police Requirements for Security Systems.

  • Humberside Police
  • Lincolnshire Police
  • North Yorkshire Police
  • South Yorkshire Police
  • West Yorkshire Police
  • Nottinghamshire Police
  • Derbyshire Constabulary
  • Greater Manchester Police

Police approval applies to intruder alarms only.

Since 1992

Established in Hull

1,750+

Systems maintained

2,850+

Scheduled service visits a year

4

Regional offices: Hull, Grimsby, Lincoln, Sheffield

Trusted across universities, NHS and healthcare, local authorities, schools and academy trusts, logistics and industrial sites, transport, and stadiums and venues.

Reviewed by the SPS Technical team · Last updated October 2026

Full accreditation details