CPR cable classes explained: Aca to Fca and s, d, a

What the CPR classes are for

The Construction Products Regulation, Regulation (EU) No 305/2011, applies to cables through the harmonised standard EN 50575:2014+A1:2016. Within its scope sit power, control and communication cables intended for permanent installation in buildings, and fibre optic cables for permanent installation are inside the same scope. For each of these cables the manufacturer declares a reaction-to-fire class in a Declaration of Performance (DoP), and the CE marking that goes with it is printed on the product label rather than on the cable itself.

The key word is reaction. A CPR class describes how a cable behaves when it is exposed to fire: how far flame spreads along it, how much heat it releases, how much smoke it produces, whether it drips burning material and how acidic its combustion gases are. It says nothing about whether the circuit keeps working during a fire. That is a separate property, circuit integrity, tested to IEC 60331, BS 6387 or the EN 50200 route used in BS 8519. A cable with a CPR class declared on the DoP may have no circuit integrity rating at all, and a fire-resistant cable still needs its own CPR class if it falls inside EN 50575. Our fire-resistant vs flame-retardant guide explains why the two are so often confused.

The main classes, Aca to Fca

The main classes run from Aca, the highest, through B1ca, B2ca, Cca, Dca and Eca down to Fca. The suffix "ca" marks a cable class and keeps it apart from the classes used for other construction products. Each step uses a different combination of test methods and a different system of third-party involvement, called AVCP (assessment and verification of constancy of performance).

The regulation defines the classes; it does not say which class a given building needs. That is set by national rules and by the project specification, often per circuit type or per escape route. Confirm the required class with the project engineer before asking for quotes, because the class drives the choice of plant as much as the construction does.

The additional classes: s, d and a

Alongside the main class, the DoP declares three additional classifications. Together they produce codes such as Cca-s1,d1,a1 or B2ca-s1a,d1,a1.

• s for smoke production: s1 is the lowest smoke class and is split into s1a and s1b; s2 and s3 allow progressively more smoke.
• d for flaming droplets and particles: d0 means none, d1 and d2 allow progressively more.
• a for acidity of combustion gases: a1 is the strictest, defined by a conductivity below 2.5 µS/mm and a pH above 4.3; a2 and a3 are less strict.

An LSZH sheath helps a cable reach good s and a results, but LSZH on its own is not a CPR class. LSZH is judged by IEC 61034 smoke density and IEC 60754 acid gas tests, covered in our smoke and acid gas test guide; the CPR class comes from its own test programme and its own DoP.

AVCP: who tests and who signs

The AVCP system tells you what paperwork to expect. Under System 1+, used for Aca, B1ca, B2ca and Cca, a notified product certification body is involved in type testing, inspects the factory and its production control, and keeps auditing samples over time. Under System 3, used for Dca and Eca, a notified laboratory carries out the type test and the manufacturer runs its own factory production control. Under System 4, used for Fca, the manufacturer declares on its own.

For sourcing this has a direct consequence. If your specification calls for Cca or above, the partner plant must already hold a System 1+ certificate for that exact construction. A plant that has a Dca test report for a similar cable cannot simply declare Cca. The desk checks the notified body number and certificate reference on the DoP and confirms them with the notified body before an order is placed; our post on verifying cable certificates shows the routine.

What to check on a quote, a DoP and a drum

1. The full class on the quote: main class plus s, d and a, for example Cca-s1,d1,a1, not "CPR compliant".
2. The DoP: a reference to EN 50575, the declared class, the product type and a unique DoP number.
3. The notified body: for System 1+ classes, the notified body number and certificate reference, checked per order.
4. The label: CE marking, class and DoP reference on the drum or coil label, as EN 50575 places them there.
5. The construction match: conductor, insulation, sheath and core count on the spec sheet match the construction the DoP covers.

For the UK, CE marking on construction products continues to be accepted in Great Britain following the ministerial statement of September 2024, and UKCA marking is optional on the same EN 50575 technical basis. Confirm the current position with your importer or test lab when the order is placed.

Common mistakes with CPR classes

Four mistakes come up repeatedly. The first is treating a CPR class as fire resistance: a high class tells you the cable contributes little to the fire, not that it keeps a fire alarm or smoke extract fan running. The second is asking for "CPR cable" without a class, which invites the lowest class a supplier can declare. The third is assuming LSZH equals Cca or B2ca. The fourth is accepting a DoP that covers a different construction from the one being made.

Our reference fire-performance construction, 0.6/1 kV Cu/Mica/XLPE/LSZH 4x25 mm2 on the fire-resistant cables page, is always quoted with the CPR class declared on the DoP and circuit integrity per test report, as two separate lines. The fire performance classes page sets the CPR system next to the IEC and BS test routes. When you send an enquiry through the quote form, give the required class per circuit type; typical MOQ and lead time wording is on the MOQ and lead time page, and every order is confirmed in writing.