What this cable is
Fire-resistant cable keeps a circuit working for a defined time while it is exposed to fire, so that emergency lighting, fire alarm panels, smoke extract fans, sprinkler pumps and evacuation lifts stay powered. The reference construction on this page is a 0.6/1 kV Cu/Mica/XLPE/LSZH 4x25 mm2 cable: an annealed copper conductor, a mica tape fire barrier lapped over it, XLPE insulation, halogen-free fillers and binder tape, and a flame-retardant low smoke zero halogen outer sheath. Outer diameter and weight are confirmed on the datasheet of the plant selected for your order; the partner catalogue table for this type repeats the figures of its standard XLPE cable line by line, so we do not quote them. The conductor still has to meet IEC 60228, 0.727 ohm/km at 20 C for 25 mm2 copper Class 2.
The mica tape is what holds the circuit together. When the XLPE burns away, the mica layer remains as an insulating barrier around the conductor. The LSZH sheath has a different job: it limits flame spread, smoke and corrosive gas while the cable burns. A cable can be LSZH without being fire-resistant, which is the most common confusion in tenders.
Two properties, separate tests
Reaction to fire and resistance to fire are proven by different tests, and a specification should name both where both are needed.
| Property | Test | What is checked |
|---|---|---|
| Circuit integrity | IEC 60331 | The circuit keeps working under flame for the stated time |
| Circuit integrity, UK | BS 6387 CWZ | Fire alone (C), fire with water (W), fire with mechanical shock (Z) |
| Circuit integrity, large cables | BS 8519 Category 1/2/3 | Life safety and firefighting systems in larger buildings |
| Flame spread | IEC 60332-1-2 single cable; IEC 60332-3 bunched | Flame does not travel along the cable beyond set limits |
| Smoke density | IEC 61034 | Light transmittance of at least 60% |
| Acid gas | IEC 60754-1 / -2 | Halogen acid at most 0.5%; pH at least 4.3, conductivity at most 10 µS/mm |
| EU reaction to fire | EN 50575 CPR class | Declared on the DoP, for example Cca-s1,d1,a1 |
All of these are per test report for a specific construction. A CPR class describes reaction to fire only; it says nothing about circuit integrity. See fire performance classes and CPR cable classes explained.
Mineral insulated option
Where a project asks for a metal-sheathed fire-resistant cable, the partner catalogue lists a 0.6/1 kV mica tape mineral insulated cable with a corrugated aluminium sheath. The 4x25 mm2 size is about 39 mm overall and about 1,749 kg per kilometre, made to the plant's enterprise standard. Because it is not made to a single international product standard, the desk reviews its fire test reports against your specification before it is offered. See mineral insulated cables.
Reading the test reports
Fire tests are type tests on a construction, not routine tests on each drum. That makes the report itself the product evidence. The desk checks four things before an order: that the tested construction matches the one on your spec sheet (conductor size range, mica layers, insulation and sheath material); that the test standard and category match your specification, for example BS 6387 CWZ rather than C only; that the report is issued by an accredited laboratory and is recent enough for your consultant; and, for EU projects, that the DoP declares the CPR class and the plant is covered by the System 1+ certification required for classes Aca to Cca. Any certificate or approval held by the partner plant is checked in the certifier's public database per order.
What you can change
- Sheath colour: red or orange are common for fire alarm and life safety circuits; the colour follows your market and consultant.
- Cores and sizes: multicore power and small fire alarm sizes, each needing a report covering that construction range.
- Armour: armoured fire-resistant versions for exposed or buried routes, offered only where the plant holds fire test reports that cover the armoured construction, because adding armour changes the tested build.
- Marking: brand, construction, test standards, CPR class where declared, year and metre marks.
Packing, MOQ and lead time
Fire-resistant cable ships on wooden or steel-wood drums with sealed end caps to keep moisture out of the cable ends during transport and site storage. Plant listings commonly show a minimum of around 500 m per size. Lead time depends on copper booking, mica taping capacity, the production slot and routine testing, and is confirmed in writing for each order. See MOQ and lead time and send your schedule through the quote form.