B2ca vs Cca vs Dca vs Eca: which cable class do you actually need?
6 min read
“B2ca or Cca?” is one of the most searched questions about cables, and it almost always gets the wrong answer: a performance comparison. The difference between the codes is measurable, but it is not enough to choose. The class you need does not depend on the cable: it depends on where it runs, who is underneath it, and which national rule governs the building.
The scale, in one line.
Seven classes, best to worst: Aca, B1ca, B2ca, Cca, Dca, Eca, Fca, all with the “ca” (cable) suffix. Each one takes three further letters: s for smoke, d for flaming droplets, a for acidity. FIGRA and THR values, the sub-classes and the verification systems are already set out in our article on the CPR codes. This one is about something else.
What really separates Eca, Dca, Cca and B2ca.
Eca sits apart. It is tested to EN 60332-1-2 on a single cable: passed if the damaged zone does not reach 425 mm. No heat measurement, no bundle. From Dca upwards the test is EN 50399: a bundle of cables on a vertical ladder, a 20.5 kW flame source, twenty minutes, with heat and smoke measured. Between Eca and Dca there is no step in performance: there is a change of test.
From Dca to Cca the geometry of the fire changes. The permitted peak heat release drops from 400 kW to 60 kW and, above all, a limit on flame spread along the bundle appears (FS ≤ 2 m) that does not exist in Dca: a Dca cable may burn along the whole specimen, provided total energy stays below the threshold.
From Cca to B2ca everything tightens. Peak from 60 to 30 kW, flame spread from 2 m to 1.5 m. That is the difference that counts where cables run vertically and in quantity: risers, shafts, service voids crossing several floors.
On site the useful question is not which class is better, but how many cables run together at that point and who walks underneath them while they burn.
Who decides: three levels, and the second one gets skipped.
The CPR classifies, it does not prescribe. Regulation (EU) No 305/2011, Article 27, empowers the Commission to establish the classes — done with Delegated Regulation (EU) 2016/364, which is only a classification system — and paragraph 6 states that member states may determine the levels or classes products must meet only in accordance with those classification systems. Europe supplies the ruler; the member state sets the threshold. Annex I requires works to be built so that “the generation and spread of fire and smoke within the construction works are limited”: an objective, not a number.
Hence the most expensive mistake in a specification: “cable compliant with the CPR” prescribes nothing at all. Fca cables are CPR-compliant too.
In Italy the threshold sits in the fire prevention code (Ministerial Decree of 3 August 2015, whose Annex 1 was replaced in full by the Decree of 18 October 2019), chapter S.1 “Reaction to fire”. The chain runs: risk profile of the area → performance level I to IV → material group GM → class. For cables, table S.1-8 is explicit:
- level IV → group GM1 → B2ca-s1,d0,a1
- level III → group GM2 → Cca-s1,d0,a2
- level II → group GM3 → Eca
The level depends on the occupants, not on the installation: escape routes in compartments where occupants receive medical care (risk profile Rvita D1 or D2, wards and intensive care) sit at level IV; those with profile B1 sit at level II. Between a ward corridor and an office corridor there are two classes of distance, and the cable has no way of knowing.
The third level is the specification, which may raise the bar: the code allows level IV also “at the specific request of the client, where set out in the technical specifications of the project”. Legitimate — but it should be written as a choice, not as a legal obligation.
What about optical fibre?
Fibre carries no current; the sheath burns all the same. The harmonised standard EN 50575 — the one that imposes CE marking and a Declaration of Performance — covers power, control and communication cables and explicitly lists optical fibre cables; its definition of “electric cable” includes optical fibre and hybrid cables. In table S.1-8 the row reads “cables for power, control and communications”: the class follows function and location, not the conductor. An optical cable in a hospital escape route needs B2ca-s1,d0,a1 exactly as a power cable does.
What does change sits in the notes to that same table. The performance is required only where the cables are not embedded in non-combustible materials; and d0 may be relaxed to d1 where the installation condition physically prevents dripping (floor laying, unperforated trunking, unperforated suspended ceilings). Between a riser in a shaft, a tray above a ceiling and a run cast into concrete, the required class may well differ. For the external section — buried duct, aerial route — ask the fire safety designer where the external works end and the compartment begins: the requirement changes there, not halfway down the drum.
One boundary not to cross: EN 50575 excludes cables that must guarantee continuity of power or signal supply to safety installations. That is fire resistance, a different family of products. You do not ask for “B2ca” from a cable that has to keep working while it burns.
How to check the class is really there.
The class is declared by the manufacturer in the DoP and printed on the sheath. On site you can verify consistency — code on the cable = DoP = specification — not performance. Ask for the DoP of the exact article code, not of the family: it must be kept for ten years from placing on the market, so it exists. On the level of independent oversight behind each class we again refer you to the other article: it is not the same for all of them.
A 2026 note: since 8 January the new Regulation (EU) 2024/3110 applies, repealing 305/2011. For cables nothing changes yet: Article 94 keeps Articles 4-9, 27 and 28 of the old CPR in force until 8 January 2040 for products covered by harmonised standards already published, and EN 50575 is one of them.
Five questions before choosing the class.
- What S.1 performance level is assigned to each area the cable crosses? Ask before writing the code.
- Does the route cross areas with different levels? Then there is more than one class.
- Does the installation exclude the requirement, or allow d1 instead of d0? It changes the price, not the safety.
- Do you need reaction to fire or continuity of service? Two different families: the second is not bought with a CPR class.
- Does the class you are asking for exist in the type of optical cable you chose? Check it on the DoP before the specification, not at the order.
Choosing the class is an act of design, not of procurement: part of the work we do when we review a specification.
Do you need to decide which class goes on an optical backbone, or to accept a delivery already on site? Talk to a technician: the right class takes half an hour to choose, the wrong one turns up at handover.