LSZH (also written LSOH or LS0H) stands for Low Smoke Zero Halogen. It describes cables whose insulation and sheathing are made from compounds that, when exposed to fire, give off very little smoke and little or no halogen gas.
This matters because conventional PVC contains halogens such as chlorine. When PVC burns it produces thick black smoke and corrosive, toxic hydrogen-chloride gas. In an enclosed building that smoke blocks visibility and the gas harms people and corrodes nearby equipment. LSZH compounds are formulated to avoid this — in a fire they stay far clearer and release negligible acidic gas, giving occupants more time to evacuate safely.
Because of this, LSZH (and the heat-resistant, flame-retardant Indian grade HR-FR-LSH) is preferred wherever many people gather or where escape routes are enclosed: hospitals, schools, malls, airports, metros and railways, industrial and commercial installations, data centres and high-rise buildings. It is increasingly chosen for homes too, for the same safety margin — see whether LSZH cables are required for homes.
It is worth distinguishing 'low smoke' behaviour from 'fire resistance': LSZH is about what a cable emits when it burns, not about keeping a circuit alive during a fire. The two properties are often combined in premium wiring.
APAR's low-smoke house wiring includes Anushakti HR-FR-LSH, Shakti FR-LSH and the Green Wire HR-FR-LSH range; the e-beam Fire Protekt (HFFR) wire adds halogen-free performance with electron-beam durability. Browse all house wires and cables to compare.