Two different questions
Reaction to fire describes what a cable does when fire reaches it: how far flame spreads along it, how much heat and smoke it releases, whether burning droplets fall and how acidic the gases are. Flame-retardant cables are designed to limit spread. Fire resistance, or circuit integrity, describes whether a cable keeps delivering power or signal while exposed to fire, which matters for fire alarms, emergency lighting, smoke extraction and sprinkler pumps. A cable can be flame-retardant without being fire-resistant. The EU CPR class covers reaction to fire only; it says nothing about circuit integrity, which needs its own test.
EU CPR classes under EN 50575
In the EU, cable permanently installed in buildings falls under the Construction Products Regulation, with EN 50575:2014+A1:2016 as the product standard. Each construction is classified Aca, B1ca, B2ca, Cca, Dca, Eca or Fca, with additional classes for smoke (s1, s1a, s1b, s2, s3), flaming droplets (d0, d1, d2) and acidity (a1, a2, a3), written for example as Cca-s1,d1,a1. The plant issues a Declaration of Performance (DoP) and the CE mark goes on the label. The level of third-party involvement depends on the class, under Decision 2011/284/EU.
| Class | AVCP system | What it means for the buyer |
|---|---|---|
| Aca, B1ca, B2ca, Cca | System 1+ | A notified body tests the type and audits the plant's production control |
| Dca, Eca | System 3 | A notified laboratory tests the type; the plant runs its own production control |
| Fca | System 4 | The plant declares performance itself |
In Great Britain, CE marking continues to be accepted following a ministerial statement in September 2024, with UKCA optional. The desk asks for the DoP and, for System 1+ classes, the notified body certificate for the exact construction; see CPR cable classes explained.
Flame spread tests: IEC 60332
IEC 60332-1-2 applies a flame to a single vertical cable and checks that the charred section stays within the limit; it is the basic flame-retardant test for most building and power cable. IEC 60332-3 tests bunched cables in a vertical ladder, the more demanding case for risers and trays. Its categories are set by the volume of non-metallic material per metre: A at 7 L/m, B at 3.5 L/m, C at 1.5 L/m and D at 0.5 L/m, with char height below 2.5 m to pass. A plant should name the category on its report; 'IEC 60332-3' on its own is incomplete.
Smoke and acid gas
LSZH cables are proved by IEC 61034 smoke density, with light transmittance of at least 60 percent, IEC 60754-1 halogen acid gas at no more than 0.5 percent, and IEC 60754-2 with pH of at least 4.3 and conductivity of no more than 10 uS/mm. These tests describe the gases, not the flame spread, so tunnels, hospitals and metros usually specify both; see insulation and sheaths.
Circuit integrity: IEC 60331, BS 6387 and BS 8519
Fire-resistant cables usually add a mica tape barrier over the conductor, under XLPE insulation and an LSZH sheath, as in the reference 0.6/1 kV Cu/Mica/XLPE/LSZH 4x25 mm2 construction; its diameter and weight are confirmed per datasheet. IEC 60331 tests circuit integrity under flame. BS 6387 adds categories for fire alone (C), fire with water (W) and fire with mechanical shock (Z), combined as CWZ. BS 8519 sets Categories 1, 2 and 3 for life safety and firefighting systems. Mineral insulated cable is an alternative: the reference mica-tape mineral insulated cable with corrugated aluminium sheath, 4x25 mm2, is about 39 mm overall and about 1,749 kg/km per the catalogue, made to an enterprise standard. See fire-resistant cables.
US ratings for data and fibre cable
For communications cable in the US, NEC ratings run CMP above CMR above CMG/CM above CMX, and a higher rating can replace a lower one. CMP is tested to NFPA 262 and CMR to UL 1666. Fibre cables use OFNP and OFNR under NEC Article 770. US projects usually require UL or other NRTL listed products to satisfy the AHJ; the listing is held by the partner plant for that construction and checked in the certifier's public database per order.
What changes price, weight and lead time
Each step up in class narrows the plants that can supply: Cca and above need notified body certification for the construction, and circuit integrity cables need mica tape lines and current reports. LSZH compound costs more than PVC. Fix the class and test list on the spec sheet before booking, then check MOQ and timing on MOQ and lead time or send the specification through the quote form.