Fire Resistant Aerial Bundled Cable 4x35mm2 LSZH Insulated Overhead Line for Public Facility Emergency Supply

This fire resistant aerial bundled cable is built for the circuits that must not fail. When a fire starts inside a hospital, a subway tunnel, a shopping mall or an underground public building, the evacuation lighting, the smoke extraction fans, the fire pumps and the lifts all depend on one thing: power that keeps flowing through the burning zone. Our 4x35mm2 overhead ABC assembly answers that requirement with a mica-based fire barrier tape wrapped directly around each stranded conductor, a cross-linked polyethylene insulation layer, and a low smoke zero halogen outer sheath that releases neither corrosive gas nor dense smoke while the cable is still energised.

Unlike a conventional indoor tray cable, this design is a self-supporting aerial bundled construction. The three phase cores and the AlMgSi alloy messenger are twisted together in a single factory assembly, so the complete bundle is strung between poles or building facades without a separate steel carrier. Installation on overhead emergency routes therefore needs no conduit, no cable tray and no additional support wire, which shortens the work of an emergency circuit upgrade from days to hours and reduces the number of joints that could fail in a fire.

• Circuit integrity under direct flame: fire barrier tape plus ceramised insulation keeps the cable operational at 950℃ for 90 minutes under IEC 60331-1, matching the escape and rescue window required for public facilities.
• LSZH safety sheath: halogen free compound meets IEC 60754-1 for acid gas and IEC 61034-2 for smoke density, protecting people in enclosed spaces and limiting damage to switchgear and control electronics.
• Self-supporting torsade structure: three insulated phase cores twisted around an AlMgSi 0.5 messenger give a rated tensile strength of 4.6 kN, allowing spans up to 45 m without a separate catenary wire.
• Overhead weather endurance: black UV stabilised sheath with 2.5 percent carbon black resists xenon arc ageing to EN ISO 4892-2, delivering a 25 year outdoor service life in coastal and industrial atmospheres.
• Aluminium conductor economy: class 2 stranded aluminium gives 61 percent of the weight of an equivalent copper conductor at roughly one third of the metal cost, cutting pole loading and total project budget.
• Wide temperature window: continuous operation from -40℃ to 90℃ with a 250℃ short circuit allowance for 5 seconds, so the line survives both alpine winters and summer overload peaks.
• Full traceability marking: meter marking, factory name, production year and standard reference are printed along the sheath for European site acceptance inspection.

The cable is specified for overhead emergency distribution where the supply route runs outside the protected room but must survive a fire inside it. Typical installations include hospital compounds where the generator house sits apart from the ward blocks, subway depots and tunnel portals, shopping centre roof plant areas, school campuses, museum courtyards, and the perimeter lighting of underground public buildings. Because the bundle is self-supporting it also suits retrofit projects where adding a steel messenger or a cable tray is impossible, and it can be tied into existing pole lines that already carry the standard ABC feeder, keeping the emergency route visually and mechanically consistent with the rest of the network.

Installation is carried out on dead line conditions using standard ABC suspension clamps and anchoring brackets. The messenger is anchored at both ends of each span, and the phase cores are terminated with compression lugs. For hazardous or highly polluted sites, we can supply a PE jacketed version with an overall oversheath that raises the protection level and extends service life in chemical plants and salt spray areas.

Every drum is a heat treated wooden drum carrying the IPPC / ISPM 15 stamp required by European plant health regulations, wrapped in UV resistant film with the drum number, gross weight, net weight and length stencilled on the flange. Standard packing is 500 m per drum; 1000 m drums and cut lengths are available against project schedules, and we can plan container loading to combine several cross sections in one 40HQ unit.

Quality control covers the full production chain. Aluminium rod is verified for conductivity before drawing, conductor resistance and strand diameter are measured on every drum, insulation thickness is checked by optical projection, and each finished length passes a 3.5 kV AC voltage test for 5 minutes together with an insulation resistance test. Fire resistant assemblies receive a sample burn test from each production batch, and third party type test reports covering IEC 60502-1 and IEC 60331-1 can be issued with the shipment for project submission. Documentation packs include the declaration of performance, RoHS and REACH statements, inspection certificates and packing lists, so the material clears customs and site acceptance without follow up questions.