What Is the CEN Grade and How Does It Relate to Padlocks?

CEN grade is a security testing standard for padlocks, created specifically to measure how resistant a padlock is to different forms of attack. CEN stands for Central European Norm, and the system was developed by major padlock manufacturers who recognised that older standards (such as those used for door locks and safes) didn’t apply well to padlocks.

Before the CEN system existed, many insurance companies were advising incorrectly—sometimes still referring to “5 lever padlocks” or outdated standards. The CEN grade solved this by providing a structured way to compare padlocks based on real-world security performance.

How the CEN Grading System Works

There are six levels in the grading system:

CEN Grade	Security Level	Typical Use
Grade 6	Maximum Security	Military, critical infrastructure, high-risk commercial
Grade 5	Extra High Security	Industrial sites, shipping yards, heavy plant
Grade 4	High Security	Warehouses, commercial gates, shutter doors
Grade 3	Medium–High Security	Sheds, workshops, business storage
Grade 2	Standard Security	General domestic use
Grade 1	Low Security	Luggage, lockers, temporary applications

For most business and home users, Grade 3 to Grade 5 offers the right balance of cost and protection.

A Quirk of the CEN System

The CEN standard is based on a series of performance tests, including:

Bolt crop resistance
Sawing resistance
Torque and twisting force
Pulling force
Corrosion/weather testing

However, if a padlock fails one part of the test, even if it performs extremely well in the others, it will be graded down to the lowest level it meets.

So a lock might perform like a Grade 6 in strength, but drop to Grade 4 simply because it didn’t pass one extreme cold-weather test.

Does Every Manufacturer Test Padlocks Properly?

No.

There is no official enforcement of the CEN grading system. Many manufacturers self-certify, meaning the grade printed on the packaging may not reflect actual performance.

The only manufacturer consistently found to independently test and accurately represent their CEN ratings is ABUS, which is why they are widely used for insurance and commercial applications.

Why CEN Is More Reliable Than “Closed Shackle Only”

Insurance forms often still say “must be a closed shackle padlock”. This is outdated guidance.

A strong open shackle CEN Grade 4 padlock can be far more secure than a weak closed shackle ungraded padlock.

If convenience or fitment requires an open shackle lock, the best approach is to ask the insurer to accept a CEN Grade, not a shackle shape.

Quick Recommendation

If in doubt, choose a CEN Grade 3, 4, or 5 padlock depending on your environment:

Grade 3 – General outdoor use
Grade 4 – Commercial and workplace security
Grade 5 – High-risk or high-value protection