In building electrical systems and home wiring, safety and reliability of materials are always the top priority.
As building density increases, decoration materials become more complex, and people pay more attention to living safety, the use of Low Smoke Halogen-Free (LSZH) materials in wiring continues to grow.
LSZH materials offer low smoke, zero halogen, flame retardancy, and environmental benefits. Because of these advantages, they have become widely used in building wiring, residential wiring, and electrical systems in public facilities.
Among them, low-smoke halogen-free silane Cross-linked polyolefin materials have grown rapidly in recent years. With stable electrical performance, good mechanical strength, and improved heat resistance after Cross-linked, they are becoming an important choice for upgrading home wiring.
LSZH (Low Smoke Halogen-Free or Low Smoke Zero Halogen) materials produce very little smoke during combustion and do not release halogen acid gases such as HCl, HF, or HBr.
They are mainly used for cable insulation and cable sheath.
Its requirements typically conform to the following international standards:
| Performance Requirements | International standards | Requirements (True Standards) |
| Halogen acid content | IEC60754-1/2 | The combined hydrogen chloride and hydrogen fluoride content is≤5mg/g, and the pH of the combustion gas is≥4.3. |
| Smoke density | IEC61034-1/2 | Light transmittance≥60% |
| Flame retardant properties | IEC60332-1/3 | There should be no sustained combustion or the flame should not spread above the marked line. |
| Low toxicity | EN 45545、GB/T 17650 | The generation of highly corrosive and toxic gases is prohibited. |
These metrics constitute almost all of LSZH core safety justifications for building and home wiring.
Statistics show that over 60% of injuries and deaths in indoor fires are caused by smoke inhalation, not by burns.
(Source: NFPA, National Fire Protection Association)
Light transmission after cable burning is important for evacuation.
IEC 61034 requires LSZH cables to keep light transmission at 60% or higher, while standard PVC materials usually reach only 20%-30%.
Low smoke means:
Clearer visibility in escape routes
Easier rescue operations
Lower risk of smoke poisoning
Because of this, LSZH wiring is preferred in homes, apartments, malls, metro stations, and other closed or semi-closed spaces.
Standard PVC releases a large amount of hydrogen chloride (HCl) when burned.
At 40℃, HCl can corrode copper, aluminum, and many metal structures. It can also form acidic condensation that damages equipment.
LSZH materials that meet IEC 60754 release almost no halogen acid gases. Even when burning, they do not produce large amounts of corrosive fumes.
This reduces the damage range after a fire and protects building systems such as low-voltage equipment, metal pipes, and HVAC systems. It also supports longer building life cycles.
Building wiring often runs through conduits or places where many cables are packed together. When short circuits, overload, or external heat occur, standard materials may accelerate flame spread.
LSZH materials meet IEC 60332 flame-retardant requirements.
They limit flame travel along the cable and reduce fire spread.
Many countries, including China, Japan, and the EU, recommend or require LSZH materials in public buildings, transport systems, hospitals, and schools.
Examples:
China’s GB 50258 and GB/T 19666 recommend B1-grade LSZH flame-retardant cables in crowded areas
EU EN 50575 sets stricter combustion performance levels for cables
LEED and BREEAM consider LSZH materials environmentally preferred
The trend in building and home wiring is clear:
LSZH is becoming the long-term mainstream, while PVC use in key areas continues to decline.
Within the LSZH family, low-smoke halogen-free silane Cross-linked polyolefin (LSZH-Si-XLPO) has gained strong market growth in recent years.
This material uses silane Cross-linked, allowing it to cure in normal humidity and achieve better heat and mechanical performance.
After Cross-linked, the long-term service temperature of the wire can reach 90℃, with short-term resistance up to 120℃.
Standard non-crosslinked LSZH materials usually support around 70℃.
This makes LSZH-Si-XLPO suitable for:
High-power home circuits (kitchens, air conditioners, floor-heating controls)
Mixed weak-current and strong-current building wiring
Areas with dense wiring that are sensitive to heat buildup
After Cross-linked，silane-XLPO shows higher tensile strength, better resistance to whitening under pressure, and stronger stress-crack resistance.
These improvements are often in the 15%-30% range, depending on formulation.
This is important for building wiring because conduits have many bends, pulling force is high, and construction environments can be tough. Better mechanical strength means longer wiring life and more reliable installation.
Silane Cross-linked helps reduce long-term electrical performance loss.
Properties such as volume resistivity and dielectric strength stay stable, and insulation performance drops less in humid environments.
This makes the material suitable for coastal regions, underground areas, and high-humidity conditions.
Silane Cross-linked does not require irradiation machines.
For many cable manufacturers, this means:
Lower equipment investment
Easier material switching
Suitable for mass production of mid-to-high-end building wires
This is one reason LSZH-Si-XLPO has grown so quickly in the wiring market
With stronger regulations, higher safety awareness, and more demand for reliable materials, LSZH materials will keep growing in the coming years.
Industry reports from IHS Markit and CRU show that global LSZH cable materials have a 7%-9% compound annual growth rate.
Building and home wiring grow even faster, and LSZH silane-Cross-linked polyolefin is becoming a key material in mid-to-high-end residential cables because it balances safety, durability, and cost.
