Insurance write-off categories explained: what are Cat N and Cat S cars?

The Cat N and Cat S car insurance write-off categories are applied to cars that have previously sustained cosmetic or structural damage. That damage will have resulted in an insurance claim and the car being designated as an insurance write-off. Cat N and Cat S cars are deemed safe to repair and return to the road, however, so they can be legally sold.

Unlike a Cat A or Cat B car, you can buy a used Cat N or Cat S car, but should you do so? There are potential risks involved in purchasing any write-off and you should certainly use extra caution. We cover all the key points to consider in detail below.

What is an insurance write-off?

When a car is involved in an insurance claim following an accident, or is damaged as a result of fire, flood or theft, the insurance company will assess it. The insurer will look at the extent of the cosmetic and structural damage to judge if it’s worth repairing.

If the insurance assessor finds that reparing the car is uneconomical, because repair work would cost more than the repaired car would be worth, they will assign the car an insurance write-off category. This indicates the extent  of the damage and the nature of any repairs that will need to be carried out to make the car roadworthy again. The write-off category must be declared by anyone selling the car in the future and gives potential buyers an extra indication as to what to look out for.

Cat N and Cat S replaced the older Cat C and Cat D categories to help better represent the complexity involved in repairing modern cars. If you are searching for a used car, it is important to note that cars that were originally assessed through the old system prior to October 2017 won’t be reassessed so they may still have Cat C or D classifications.

What is Cat S and Cat N damage?

A Cat S car is one which has sustained structural damage – think of items integral to the car's structure such as the chassis and suspension. While Cat S cars can safely be repaired and put back on the road, they must be re-registered with the DVLA.

Cat N classification encompasses damage to all non-structural damage, such as body panels, lights, and electrical systems. As with Cat S cars, Cat N vehicles can be put back on the road but they do not need to be re-registered with the DVLA – though you will still need to inform the DVLA your car has been written-off in the first place.

In effect, Cat N and Cat S replace the old Cat D and Cat C categories respectively, albeit with modifications to their remits.

What does Cat S and Cat N damage mean?

The write-off categories are intended to reflect the type of damage sustained by a car that caused it to be written off. Knowing this information will go some way towards helping a future buyer understand what to look for when inspecting the car. Knowing that a car was previously structurally damaged is particularly important as poor repairs can be easier to hide from all but the most thorough of inspections.

Conducting a background check, such as those undertaken by Hire Purchase Investigation (HPI), should also reveal this categorisation as an alert on the car’s history. The registration certificate – the V5C – will also be marked with an ‘S’ to signify that the car has been salvaged.

What are Cat A and Cat B cars? 

If a car is damaged beyond the point that an insurer believes it can be safely returned to the road, it will be classified as either Cat A or Cat B.  Cat A cars have to be crushed, and none of their parts can ever legally be reused. Cat B (the ‘B’ stands for ‘break’) cars also have to have their body shells crushed, but can be broken up for parts before that happens, with salvageable components being resold.

Insurance write-off categories at a glance

• A. Scrap
• B. Break
• S. Structurally damaged repairable
• N. Non-structurally damaged repairable

Should I buy a Cat S or Cat N car?

The same caveats apply to Cat S or Cat N cars as apply to Cat C and Cat D vehicles: buyer beware.

Firstly, conducting a background check on a car should show whether it has ever been declared as a write-off. A seller is legally required to inform a potential buyer of this fact, so if they fail to do so, walk away as they could be trying to illegally cover up the vehicle's past. 

Once you have determined a car’s history, it’s important to be sure of the standard of all repairs carried out when the car was returned to the road. If you are viewing a potential write-off purchase, it is a very good idea to get a professional inspection before signing any paperwork - this is particularly important with structurally-damaged Cat S cars.

Another thing to be aware of is that insurance can be harder to come by for previously written-off cars, with some providers not covering them at all. While this can be overcome by hunting around, insurance for Cat S and N cars (likewise C and D) tends to be more expensive than it is for non-written-off cars.

Written-off cars are also worth less than their undamaged counterparts. While this should be reflected in their purchase price, you may find it hard to sell a Cat S or Cat N car, as some buyers will simply not consider them.

Looking for a used bargain? Take a look at our best cars for £5,000 or less and get personalised car insurance quotes using our tool...