Cable myth-buster: CPR

In the final instalment of a three-part series debunking common cable misconceptions, Paul Bellamy, Managing Director of flex7, discusses CPR and why – confusing as it might be – it’s not going anywhere.

“Since Brexit, CPR is not a requirement in the UK.” Sorry, that’s wrong. Just like many of the rules and regulations that govern our everyday lives here in the UK, not much has really changed since Brexit and, with respect to CPR, that’s a very good thing.

The requirement for cables to be CPR-tested, classified and certified became mandatory in the UK in July 2017, and that legal requirement remains in place today. CPR provides everyone responsible for specifying or selecting a cable for installation the means to compare one against another in respect of its reaction to fire in a way that was almost impossible before its introduction.

Testing systems and categories

Broken down into seven Euroclass categories, the way a cable will react to fire ranges from ‘Unknown’ (F_CA) to ‘No Reaction’ (A_CA). Between these two extremes are a further five categories and two testing systems. Products that fall into Euroclass E_CA or D_CA are tested using System 3, whereas products from C_CA through to A_CA must undergo the far more rigorous System 1+.

Without going into the nitty-gritty of the different testing systems and category requirements (and there’s a lot of nitty-gritty to wade through), a simple rule of thumb for anyone selecting cables for installation in public or densely populated buildings (schools, hospitals, offices, etc.) would be to head straight for those tested to System 1+ as a starting point. These have gone through stringent testing by an authoritative body such as BASEC and must be retested on a regular basis. System 3 products are tested once with no requirement to be tested again, ever.

The certification and Declaration of Performance that is issued against a System 1+ product is also far more detailed, and rather than just showing the overarching Euroclassification, for example D_CA, goes on to give information relating to smoke propagation, burning droplets of molten material produced and the acidity of any harmful gases emitted – an example would be C_CA s1a, d1, a1.

It’s also worth noting that a higher classification can be used where a lower classification is specified, but not the other way round.

Easier cable selection

Remember, CPR is only focused on a cable’s reaction to fire and, generally, the higher the Euroclass, the more expensive the product. For example, a cable in the E_CA class is probably there because it uses PVC compounds which are relatively cheap. At the other end of the spectrum is A_CA where we’re looking at something like an MICC cable, and I doubt many of us would expect to buy 100m of pyro for the same price as 100m of PVC T&E.

The subject of CPR can be daunting, but fundamentally it’s a great tool to have at the disposal of those tasked with cable selection. For that reason alone, we should be glad it wasn’t gleefully lobbed back across the English Channel at the end of January 2020.

So, there we have it. Three common cable misconceptions that, when taken at face value, seem perfectly reasonable – no doubt the reason they’ve gained traction in the first place. Dig a little deeper, though, and it becomes obvious why they don’t hold water: BASEC is not the world’s police for cable (and I doubt it wants to be); LSF and LSHF cables are produced using completely different compounds; and CPR makes cable selection for reasons of safety 100% easier than it used to be.

flex7.co.uk

This article appeared in Electrotechnical News May/June 2026 edition – read it here

Part one of the cable myth-buster series looked at BASEC approval – read it here. Part two looked at LSF and LSHF cables – read it here.