Grading of Intruder Alarm Systems Explained

Crism Security | Deltabell Alarm Installations in Doncaster

People ask me what does a Graded Intruder Alarm mean? Do I need a graded one? Do I need to check my present alarm? How do I know if it is graded if I have no paperwork and I have inherited the system? So, I hope I can clarify some of your queries…

Insurance companies normally require intruder alarm systems to be graded (often specifying what grade the system should be installed to) This is so they know that the design of the system will meet the risks of an intruder breaking into your building.

A risk assessment is always done by an accredited installer to assess what grade the intruder alarm system should be installed to

Intruder alarm systems are graded from Grade 1 to Grade 4:


Grade 1is to protect the premises against an intruder who has very basic knowledge and very basic tools.
Grade 2is to protect the premises against an intruder who has knowledge of intruder alarm systems and some more advanced tools that they may use to get around the system.
Grade 3is designed to protect the premises from an intruder who has full knowledge of installing intruder alarm systems and has, at their disposal, the full set of tools they would need to overcome the system.
Grade 4is for the highest risk premises, typically museums, jewellers, financial institutions, banks. These systems usually have a direct link to the local police force.


All graded installations are certificated to ensure they comply with the EN and BS standards.

Ungraded installations are not designed to meet any risks to your premises and would probably be installed without consideration or the knowledge required for adequate protection. An intruder novice can get round this system easily.

If you have an Intruder Alarm and have no idea if it is a graded system ask an accredited Security Installer to assess it for you (SSAIB, NACOS).

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