Your NSI approved intruder alarm company meets all relevant standards and understands your security needs

NSI approved companies will discuss all available intruder alarm options that suit your property and requirements

The right type of home alarm for you

Any NSI approved company will explain the spectrum of choice from simple home alarm systems with an audible (alarm) warning and visual deterrent, to more sophisticated systems which can summon a Police response. These include those that incorporate CCTV robustly connected to Alarm Receiving Centres (ARC) 24/7 remote monitoring services ensuring Police response at all times. State of the art solutions include stand-by power options and always connected dedicated multi path alarm signal transmission.

Many solutions provide the add-on of internet-enabled phone app alerts with varying degrees of resilience and security for your house.

All intruder alarm systems for your home are routinely maintained by your installer and any malfunctioning components replaced, where a maintenance contract is in place. A system wide health check is performed including Standby batteries. As part of a routine maintenance back up batteries are replaced typically every two to four years.

Search NSI's Company Finder for approved companies in your local area.

Homeowners assured of the quality and technical standards of all NSI approved installers

Choosing an NSI approved company

NSI approved companies are qualified to design, install and maintain alarms to professional industry, Police and insurer recognised standards - including PD 6662 and/or BS 8418 for detector activated CCTV alarm systems, ensuring activation.

They will issue you with a Certificate of Compliance and apply for alarm monitoring, Police or keyholding response on your behalf according to your needs.

Properties with a clearly visible professionally installed alarm make intruders think twice, whether they will summon the Police via a 24/7 monitoring service or simply sound an audible alarm.


Alarm monitoring

A sophisticated 24/7 remotely monitored alarm provides the highest level of security for your home at all times. An audible warning device ('bells only') simply sounds, relying on anyone in earshot to take appropriate action.

Alarm monitoring services arranged by your NSI approved company are also NSI approved, and meet stringent security and business continuity requirements, ensuring resilient comprehensive 24/7 monitoring of your home.

Alarm Receiving Centres (ARCs) and Remote Video Response Centres (RVRCs) can verify any alarm signals, filtering out identifiable false alarms, and notify accordingly the Police, an appointed keyholder and/or the householder. At the time of installation your installer will demonstrate the use of the system, including avoiding false alarms. Find out more about Police Response below.


Alarm monitoring services will notify:

Your nominated key holders

Your contracted keyholding company

Security Alarm icon

The Police in the event of a confirmed alarm

Should I contact my Insurer?

Your insurance company may require you to have an intruder alarm installed depending on the risk level of your property. 

They may also require that your alarm system is installed and regularly maintained by an NSI Gold or Silver approved company and they may ask for documentation to confirm the alarm has been installed in line with their requirements.

You may be entitled to receive a discount if your intruder alarm meets your insurer's requirements.

Check with your insurance company when you apply for or renew a Policy to avoid losing out. If you are using an insurance broker to arrange your insurance, make sure they check this for you.

Insurer conditions

You should also check the type of alarm system you need: either a remotely monitored or a warning devices-only alarm. A monitored alarm is likely to be required for higher risk properties.

Once your NSI approved company has installed your alarm system, you will be issued with an NSI Certificate of Compliance that can be presented to the insurer as required.

Your insurance cover may be invalidated if a burglary occurs when the property has been left unattended and the alarm system has not been armed (“set”) correctly.

What is Police response?

Police Policy is designed to ensure efficient deployment of responders to intruder alarms.

In order to obtain Police response to an alarm in the UK, it is essential to use the services of:

  • an approved installer recognised by the Police, and
  • an approved Alarm Receiving Centre (ARC)

The Police require your alarm system to be installed and maintained routinely. Your NSI approved installer can do this.

Installers holding NSI Gold or Silver approval are recognised by the Police.

NSI approved installers will provide you with a contract covering alarm monitoring services provided by an NSI approved Alarm Receiving Centre, as well as maintenance, unless you choose otherwise. They will also provide:

  • A Certificate of Compliance to PD 6662 for your installation.
  • Explain how a Police Unique Reference Number (URN) can be obtained. This means your alarm system will be registered with your local Police Force.

You can check the authenticity of the company by asking to see its Certificate of Approval or check on the NSI Company Finder.

The Police Response in England, Wales and Northern Ireland

The Police in England, Wales and Northern Ireland will only register and respond to alarm systems that meet the requirements of the National Police Chiefs’ Council (NPCC).

In the UK, excluding Scotland, the Police commit to immediate response (subject to priorities). However;

  • Immediate response will be withdrawn following three false alarm calls in a rolling twelve-month period.  
  • Reinstatement of response can follow the identification of the cause of false alarms and demonstrating appropriate remedial action has been taken.

To receive Police response for a remotely monitored alarm system, any systems newly installed (since June 2019) must conform to PD 6662:2017 and BS 8243:2021. For systems installed prior to this date they must conform to PD 6662:2010 and BS 8243. 

The Police Response in Scotland

The Police in Scotland will only register and respond to alarm systems that meet the requirements of the Police Scotland Policy.

Police response is provided according to the following levels:

Level One – Immediate / Urgent

Level Two - desirable but dependent on resources

Level Three - no Police response (keyholder attendance required)

Police will operate Level One response for all newly installed systems. However;

  • Following three false calls from a system in a twelve-month period, Level One - priority response is downgraded to Level Two.
  • For Level One to be reinstated the system problem must be rectified and remain false alarm free for three months.
  • Where a further two false alarm calls occur in the same twelve month period, the system is downgraded to Level Three.

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NSI Gold and Silver Medals - Signifying a companies approval with NSI

Look out for the NSI hallmark

It’s the most widely recognised mark of approval in security and
fire safety. NSI approval tells you the company is:


Technically Competent

Working to International and British Standards and NSI Codes of Practice, teams have relevant technical experience


Gold approval - operating a Quality Management System to ISO 9001 and NSI Quality Schedules


Reputable Directors & leaders with relevant business experience and effective employee security screening

Find an NSI approved company