What Is the Difference Between LSZH and Fire-Resistant Cables?

Fire-Safe Cabling for Data Centers and Public Buildings: LSZH and Fire-Resistant Cables Explained

Large technology companies have raised their 2026 spending on computing infrastructure sharply, and every new data center needs enormous quantities of power and data cable. The same pattern applies to hospitals, airports, metro stations and high-rise offices. In all of these places, people and equipment are packed into a small space, so what the cable does during a fire matters as much as how it performs on a normal day.

Why Smoke Is the Real Danger

Most fire casualties come from breathing smoke and toxic gas rather than from flames. Ordinary PVC cable gives off dense smoke and corrosive hydrogen chloride when it burns. Low smoke zero halogen (LSZH) cable uses a polyolefin-based compound with no halogens, so it releases far less smoke, keeps visibility better for evacuation, and produces gases that do much less damage to electronic equipment and sprinkler-wetted racks.

Flame Retardant, Fire Resistant and LSZH Are Not the Same

The distinction is important when writing a specification. A cable can be flame retardant and still give off heavy smoke, and an LSZH cable does not necessarily keep working after the flame reaches it. Emergency circuits usually need both properties together.

How Fire-Resistant Cable Is Built

A typical fire-resistant electrical wire has a copper conductor wrapped with a mica tape layer, followed by the insulation. When flame reaches the cable, the outer material burns away, but the mica layer stays in place and continues to separate the conductor from adjacent conductors and metal parts, so the circuit keeps supplying power for the time stated in the test standard. This is why such cables are specified for fire pumps, sprinkler pumps, smoke exhaust fans and the main distribution lines that serve them.

Points to Check Before Ordering

• The fire classification required in the destination market. In Europe this is the Construction Products Regulation Euroclass, such as Cca for many commercial buildings, while other regions use their own national or IEC test standards.
• Test reports for halogen content, smoke density and gas acidity, not only a general LSZH label on the datasheet.
• Rated voltage and conductor size matched to the circuit load, with allowance for voltage drop on long runs.
• Armor or sheath choice. Steel-tape armored cables allow direct burial and cable trench installation with added mechanical protection.

Fire-Safe Cable Options from Hu'an Cable

Shanghai Hu'an Cable (Wuxi) Co., Ltd. produces fire-resistant wires, fireproof cables and eco-friendly low-smoke halogen-free cables, and its low-voltage power cables are available in flame-retardant, fire-resistant and halogen-free versions. Products are made to GB/T standards and carry CE, RoHS and VDE approvals for export. If you are planning a data center, commercial building or industrial site, send your project details to receive a specification recommendation and quotation.