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Low Smoke Zero Halogen (LSZH) Power Cable — Technical Reference
This document compiles comprehensive technical data for Low Smoke Zero Halogen (LSZH/LSOH/LS0H) power cables, covering three major standard systems — Chinese National Standards (GB), European Standards (EN/IEC), and American Standards (UL) — for building a product promotional website.
1. Product Overview
1.1 What is an LSZH Cable
Low Smoke Zero Halogen Cable (abbreviated LSZH / LSOH / LSHF / LS0H) is an environmentally friendly cable whose insulation and sheath materials contain no halogens (fluorine, chlorine, bromine, iodine, etc.), produce low smoke density when burning, and release no toxic halogen acid gases.
“Low Smoke” means: The cable produces low smoke density when burning, with light transmittance ≥60%, maintaining good visibility during a fire to facilitate evacuation and firefighting rescue.
“Zero Halogen” means: The insulation and sheath materials contain no halogen elements, releasing no toxic, corrosive gases such as hydrogen chloride (HCl) or hydrogen bromide (HBr) when burning, reducing harm to people and corrosion to equipment.
1.2 Core Safety Value
| Safety Dimension |
Conventional PVC Cable |
LSZH Cable |
| Smoke emission |
High smoke density, transmittance ≤30% |
Low smoke density, transmittance ≥60% |
| Halogen content |
Contains chlorine and other halogens |
Halogen-free |
| Toxic gas release |
High (HCl ≥3000 ppm) |
Extremely low (CO ≤50 ppm) |
| Corrosive gases |
Severe (corrodes circuit boards and equipment) |
Minimal |
| Fire safety rating |
Medium |
High |
| Environmental friendliness |
Contains halogens, hard to degrade, pollutes |
Recyclable, RoHS compliant |
According to fire statistics, 80% of fire casualties result from inhaling toxic gases or suffocation in dense smoke. LSZH cables help protect the “golden escape time” during a fire.
2. Applicable Standards
2.1 Chinese National Standards (GB/T)
| Standard No. |
Standard Title |
Scope |
| GB/T 12706.1-2020 |
Power cables with extruded insulation and accessories for rated voltages 1 kV (Um 1.2 kV) up to 35 kV (Um 40.5 kV) — Part 1: Cables for rated voltage 1 kV and 3 kV |
0.6/1 kV power cables |
| GB/T 19666-2019 |
General rules for flame-retardant and fire-resistant wires, cables or optical cables |
General standard for flame-retardant/fire-resistant cables |
| GB 31247-2014 |
Classification for burning behavior of cables and optical cables |
Burning performance classification (mandatory) |
| GB/T 18380 series |
Tests on electric and optical cables under fire conditions |
Flame retardancy testing |
| GB/T 17651.2-2021 |
Measurement of smoke density of cables burning under defined conditions |
Smoke density testing |
| GB/T 17650.1-2021 |
Tests on gases evolved during combustion of materials from cables — Part 1: Determination of the halogen acid gas content |
Halogen acid gas testing |
| GB/T 17650.2-2021 |
Tests on gases evolved during combustion of materials from cables — Part 2: Determination of acidity (corrosivity) of gases by measuring pH and conductivity |
Gas acidity testing |
| GB/T 19216.21 |
Circuit integrity test for cables under fire conditions |
Fire resistance testing |
| GB/T 3956-2008 |
Conductors for insulated cables |
Conductor specification requirements |
| GB/T 2951.11-2008 |
Common test methods for insulating and sheathing materials of electric cables |
Mechanical property testing |
| GB 50217 |
Standard for design of cables of electric power engineering |
Engineering design and selection |
| GB/T 26572 |
Requirements of concentration limits for certain restricted substances in electrical and electronic products |
Environmental requirements |
2.2 European Standards (EN/IEC)
| Standard No. |
Standard Title |
Scope |
| EN 50525-3-11 |
Cables rated 300/500 V and 450/750 V — Low smoke zero halogen cables |
Main European LSZH cable standard |
| EN 50525-3-21 |
Single-core halogen-free flexible conductors (H07Z-K / H05Z-K) |
Single-core wiring cables |
| EN 50575:2014+A1:2016 |
CPR fire performance assessment for construction cables |
EU Construction Products Regulation (mandatory) |
| EN 50399 |
Flame spread, heat release and smoke production test (large scale) |
CPR classification test method |
| EN/IEC 60228 |
Conductors of insulated cables (Class 1/2/5/6) |
Conductor standard |
| EN/IEC 60332-1-2 |
Test on single vertical insulated wire or cable |
Single cable flame retardancy |
| EN/IEC 60332-3-24 |
Test on bunched wires or cables (Category C) |
Bunched cable flame retardancy |
| EN/IEC 60754-1/2 |
Halogen acid gas content and acidity tests |
Halogen-free performance testing |
| EN/IEC 61034-1/2 |
Smoke density test (3 m³ cube method) |
Low smoke performance testing |
| EN 60811 series |
Common test methods for insulating and sheathing materials |
Material/mechanical properties |
| EN 50288-7 |
Digital communication cables |
Control cables |
| EN 50618 |
Solar photovoltaic cables |
PV LSZH cables |
| IEC 60502-1 |
Power cables rated 1 kV up to 30 kV |
Power cables |
| BS 7211 / BS 6724 |
British LSZH cable standards |
UK market |
2.3 American Standards (UL/ASTM)
| Standard No. |
Standard Title |
Scope |
| UL 758 |
Appliance wiring material cables and test methods |
Electronic/hook-up wires |
| UL 1581 |
Reference standard for electrical wires, cables and flexible cords |
General testing standard |
| UL 44 |
Thermoset-insulated wires and cables |
XHH and similar types |
| UL 1277 |
Electrical power and control tray cables (TC-ER) |
Outdoor/building cables |
| UL 1685 |
Cable smoke density and toxicity testing |
Smoke/toxicity testing |
| UL 2196 |
Fire-resistant cable system testing |
Fire resistance |
| UL VW-1 |
Vertical wire flame test |
Flame rating |
| CSA C22.2 No.230 |
Canadian TC-ER cable standard |
North American market (CUL) |
| CSA C22.2 No.2556-15 |
Canadian flame tests FT1/FT2 |
Flame ratings |
| ASTM B3/B8/B33 |
Conductor standards |
Bare copper / tinned copper conductors |
| ASTM D2863 |
Oxygen index test |
Flame retardancy |
| ASTM E662 |
Smoke density test (NBS smoke chamber) |
Smoke density |
| ASTM G154 |
UV weathering test |
Weather resistance |
| NFPA 130 |
Fire safety standard for fixed guideway transit and rail |
Metro/rail transit |
| NFPA 75/76 |
Data center fire protection standards |
Data centers |
3. Type Designation System
3.1 Chinese National (GB) Designation
Naming rule: Burning characteristic code + insulation material + sheath material + (armor code)
Burning Characteristic Codes (GB/T 19666-2019)
| Code |
Meaning |
Description |
| W |
Halogen-free (Wu-halu) |
Insulation/sheath contains no halogen |
| D |
Low smoke (Dan-yan) |
Burning transmittance ≥60% |
| Z |
Flame retardant (Zu-ran) |
Flame retardant performance |
| ZA |
Category A flame retardant |
Highest flame retardant rating |
| ZB |
Category B flame retardant |
High flame retardant rating |
| ZC |
Category C flame retardant |
Common flame retardant rating |
| ZD |
Category D flame retardant |
Basic flame retardant rating |
| N |
Fire resistant (Nai-huo) |
Maintains circuit integrity ≥90 min in fire |
When multiple burning characteristics are required, codes are arranged in the order: halogen-free (omitted if halogenated) → low smoke → low toxicity → flame retardant → fire resistant.
Insulation/Sheath Material Codes
| Code |
Meaning |
| YJ |
Cross-linked polyethylene insulation (XLPE) |
| Y |
Polyolefin sheath |
| V |
Polyvinyl chloride (PVC, halogenated) |
| E |
Low smoke zero halogen polyolefin |
Construction/Usage Codes
| Code |
Meaning |
| B |
Building wire (fixed installation) |
| R |
Flexible cord (stranded flexible conductor) |
| K |
Control cable |
| P |
Shielded |
| S |
Twisted pair |
| 22 |
Steel tape armored |
| 23 |
Steel tape armored with polyolefin outer sheath |
| 33 |
Fine steel wire armored |
Common Type Examples
| Type |
Full Name |
Typical Application |
| WDZ-BYJ |
Halogen-free low smoke flame retardant XLPE insulated building wire |
Residential/commercial fixed wiring (450/750 V) |
| WDZ-RYJ |
Halogen-free low smoke flame retardant XLPE insulated flexible cord |
Conduit/movable wiring |
| WDZN-BYJ |
Halogen-free low smoke flame retardant fire resistant XLPE building wire |
Fire protection / emergency lighting |
| WDZ-YJY |
Halogen-free low smoke flame retardant XLPE insulated polyolefin sheathed power cable |
Power distribution (0.6/1 kV) |
| WDZA-YJY |
Category A halogen-free low smoke flame retardant power cable |
Metro / tunnels / super high-rise |
| WDZB-YJY22 |
Category B halogen-free low smoke flame retardant steel tape armored power cable |
Direct burial / tunnels |
| WDZN-YJY |
Halogen-free low smoke flame retardant fire resistant power cable |
Fire power supply / emergency circuits |
| WDZB1-YJY |
B1 grade high flame retardant LSZH power cable |
GB 31247 high-grade applications |
| WDZ-KYJY |
Halogen-free low smoke flame retardant control cable |
Industrial automation / signal transmission |
| WDZN-KYJYP2 |
Halogen-free low smoke flame retardant fire resistant copper tape shielded control cable |
Fire linkage / alarm systems |
3.2 European Designation
| European Type |
Standard |
Meaning |
| H07Z-K |
EN 50525-3-21 |
450/750 V single-core halogen-free flexible conductor |
| H05Z-K |
EN 50525-3-21 |
300/500 V single-core halogen-free flexible conductor |
| H07Z1Z1H2-F |
EN 50525-3-11 |
450/750 V multi-core LSZH equipment connection cable |
| N2XH |
IEC 60502-1 |
0.6/1 kV XLPE insulated LSZH sheathed power cable |
| RE-2X(st)H LSZH |
EN 50288-7 |
LSZH control/instrumentation cable |
| NHXMH |
EN 50525 |
European halogen-free power cable (common in Netherlands/Germany) |
3.3 American Designation
| American Type |
Standard |
Meaning |
| UL 3385 |
UL 758 / UL 1581 |
300 V XLPE insulated low smoke zero halogen electronic wire |
| UL 3886 |
UL 758 / UL 1581 |
1500 V XLPE insulated low smoke zero halogen electronic wire |
| UL 21143 |
UL 758 / UL 1581 |
300 V/600 V low smoke zero halogen cable (equipment wiring) |
| XHH |
UL 44 |
600 V XLPE insulated single conductor cable (LSZH version available) |
| XHHW-2 |
UL 44 |
600 V XLPE insulated moisture-resistant cable |
| TC-ER (UL 1277) |
UL 1277 |
600 V tray cable (LSZH version available) |
4. Technical Parameters
4.1 Conductor DC Resistance (GB/T 3956 / IEC 60228)
Maximum DC resistance of copper conductors at 20°C (Ω/km):
| Nominal Cross-Section (mm²) |
Max DC Resistance (Ω/km) |
Nominal Cross-Section (mm²) |
Max DC Resistance (Ω/km) |
| 1.5 |
12.1 |
95 |
0.193 |
| 2.5 |
7.41 |
120 |
0.153 |
| 4 |
4.61 |
150 |
0.124 |
| 6 |
3.08 |
185 |
0.0991 |
| 10 |
1.83 |
240 |
0.0754 |
| 16 |
1.15 |
300 |
0.0601 |
| 25 |
0.727 |
400 |
0.0470 |
| 35 |
0.524 |
500 |
0.0366 |
| 50 |
0.387 |
630 |
0.0283 |
| 70 |
0.268 |
— |
— |
4.2 Reference Current-Carrying Capacity (0.6/1 kV, in free air, ambient 40°C)
Copper conductor armored cables (A):
| Nominal Cross-Section (mm²) |
2-Core |
3-Core |
3+1 Core |
4-Core |
| 2.5 |
26 |
30 |
26 |
35 |
| 4 |
37 |
44 |
35 |
44 |
| 6 |
46 |
52 |
44 |
52 |
| 10 |
61 |
70 |
57 |
70 |
| 16 |
80 |
87 |
74 |
87 |
| 25 |
111 |
113 |
100 |
113 |
| 35 |
139 |
135 |
126 |
135 |
| 50 |
165 |
161 |
152 |
161 |
| 70 |
218 |
196 |
191 |
196 |
| 95 |
261 |
235 |
235 |
235 |
| 120 |
305 |
265 |
274 |
265 |
| 150 |
348 |
300 |
313 |
300 |
| 185 |
400 |
339 |
365 |
339 |
| 240 |
479 |
396 |
435 |
396 |
| 300 |
522 |
452 |
522 |
457 |
Direct burial current ratings (soil temperature 25°C):
| Nominal Cross-Section (mm²) |
2-Core |
3-Core |
3+1 Core |
4-Core |
| 2.5 |
40 |
30 |
35 |
30 |
| 4 |
55 |
40 |
50 |
40 |
| 6 |
65 |
50 |
60 |
50 |
| 10 |
90 |
65 |
80 |
65 |
| 16 |
110 |
85 |
100 |
85 |
| 25 |
140 |
115 |
130 |
115 |
| 35 |
180 |
145 |
155 |
145 |
| 50 |
210 |
175 |
185 |
175 |
| 70 |
250 |
220 |
225 |
220 |
| 95 |
285 |
270 |
270 |
270 |
| 120 |
330 |
315 |
305 |
315 |
| 150 |
375 |
360 |
345 |
360 |
| 185 |
420 |
420 |
390 |
420 |
| 240 |
500 |
500 |
455 |
500 |
| 300 |
580 |
550 |
520 |
585 |
Ambient temperature correction factors:
| Ambient Temperature |
20°C |
25°C |
30°C |
35°C |
40°C |
| Air correction factor |
1.04 |
1.0 |
0.96 |
0.92 |
0.87 |
4.3 WDZ-BYJ Building Wire Current Ratings (450/750 V)
| Nominal Cross-Section (mm²) |
Exposed (25°C) |
In Conduit 2–3 (25°C) |
In Conduit 4+ (25°C) |
In Plastic Conduit (25°C) |
| 1.5 |
25 |
20 |
17 |
19 |
| 2.5 |
35 |
28 |
24 |
27 |
| 4 |
48 |
39 |
34 |
37 |
| 6 |
65 |
53 |
46 |
50 |
| 10 |
95 |
77 |
67 |
73 |
| 16 |
130 |
105 |
91 |
100 |
Correction factor at 35°C: 0.86; at 40°C: 0.78.
4.4 Electrical Performance Parameters
| Parameter |
Value |
| Rated voltage |
300/500 V, 450/750 V, 0.6/1 kV |
| Test voltage |
2500 V AC (5 min without breakdown) |
| Insulation resistance (20°C) |
≥20 MΩ·km (power cables); ≥100 MΩ·km (control cables) |
| Long-term operating temperature |
70°C (polyolefin) / 90°C (XLPE) / 105–125°C (radiation cross-linked) |
| Maximum short-circuit temperature |
250°C (duration ≤5 s) |
| Conductor volume resistivity (20°C) |
≤0.017241 Ω·mm²/m (oxygen-free copper) |
4.5 Mechanical and Environmental Parameters
| Parameter |
Value |
| Installation temperature |
≥0°C (fixed installation) |
| Bending radius (fixed) |
Single-core unarmored: 20D; multi-core unarmored: 15D; single-core armored: 15D; multi-core armored: 12D |
| Bending radius (flexible use) |
≥15D (≥10D for European control cables) |
| Operating temperature range (fixed) |
-40°C to +70°C (polyolefin) / -40°C to +90°C (XLPE) |
| Operating temperature range (flexible) |
-5°C to +70°C |
| Tensile strength |
≥12 MPa (polyolefin) / ≥18 MPa (XLPE) |
| Elongation at break |
≥125% |
D = actual cable outer diameter (mm)
5. Flame Retardancy Classification
5.1 GB Flame Retardant Categories (GB/T 19666)
| Code |
Non-Metallic Volume (L/m) |
Flame Application (min) |
Pass Criteria |
Test Method |
| ZA |
7 |
40 |
Charred extent ≤2.5 m |
GB/T 18380.33 |
| ZB |
3.5 |
40 |
Charred extent ≤2.5 m |
GB/T 18380.34 |
| ZC |
1.5 |
20 |
Charred extent ≤2.5 m |
GB/T 18380.35 |
| ZD |
0.5 |
20 |
Charred extent ≤2.5 m |
GB/T 18380.36 |
ZD applies to small wires and cables with outer diameter ≤12 mm.
5.2 GB Burning Performance Classification (GB 31247-2014, Mandatory)
| Class |
Flame Spread |
Peak Heat Release Rate |
Total Heat Release (1200 s) |
FIGRA |
Peak Smoke Production |
Total Smoke (1200 s) |
Smoke Density (Min Transmittance) |
| B1 |
≤1.5 m |
≤30 kW |
≤15 MJ |
≤300 W/s |
— |
— |
≥60% |
| B2 |
≤2.5 m |
≤60 kW |
≤30 MJ |
≤300 W/s |
≤1.5 m²/s |
≤400 m² |
≥60% |
5.3 EU CPR Fire Classes (EN 50575)
| Class |
Performance |
Typical Application |
AVCP System |
Surveillance |
| Aca |
Non-combustible, zero heat release |
Very few special cases |
System 1+ |
2 factory audits/year, full retest every 3 years |
| B1ca |
Extremely difficult to ignite, very low heat release |
Very high fire risk / extreme environments |
System 1+ |
2 factory audits/year, full retest every 3 years |
| B2ca |
Very limited flame spread |
High fire load areas |
System 1+ |
2 factory audits/year, full retest every 3 years |
| Cca |
Limited flame spread |
Offices / residential / hotels and other crowded areas |
System 1+ |
2 factory audits/year, full retest every 3 years |
| Dca |
Basically flame retardant |
Some residential or low-risk areas |
System 3 |
No ongoing surveillance |
| Eca |
Minimum compliance level |
Low-risk non-continuous areas |
System 3 |
No ongoing surveillance |
| Fca |
Fail |
Not usable where fire performance is required |
System 4 |
No ongoing surveillance |
CPR Additional Classification Labels:
| Category |
Classes |
Meaning |
| Smoke production (s) |
s1a / s1b / s2 / s3 |
s1 lowest smoke, s3 highest smoke |
| Acidity (a) |
a1 / a2 / a3 |
a1 low corrosivity, a3 high corrosivity |
| Flaming droplets (d) |
d0 / d1 / d2 |
d0 no droplets, d2 no requirement |
CPR Core Test Criteria (B2ca class):
| Metric |
Limit |
| FIGRA (fire growth rate index) |
≤150 W/s |
| Peak HRR (heat release rate) |
≤40 kW |
| THR1200s (total heat release over 1200 s) |
≤20 MJ |
5.4 American Flame Ratings
| Test Standard |
Rating |
Meaning |
| UL 1581 VW-1 |
— |
Vertical wire flame test, self-extinguishing |
| CSA FT1 |
— |
Canadian vertical flame test, self-extinguishing |
| CSA FT2 |
— |
Horizontal flame test |
| IEC 60332-1-2 |
— |
Single vertical cable test (international) |
| UL 94 V-0 |
V-0 |
Self-extinguishes within 30 s, no flaming drips |
| UL 94 V-1 |
V-1 |
Self-extinguishes within 30 s, drips allowed |
| ASTM D2863 (LOI) |
≥32% |
Oxygen index test |
6. Halogen-Free and Low Smoke Performance
6.1 Halogen-Free Performance (GB/T 17650 / IEC 60754)
| Test Item |
Unit |
Pass Criterion |
Test Method |
| Total halogen acid gas (HCl+HBr) |
% |
≤0.5 |
GB/T 17650.1 / IEC 60754-1 |
| Fluorine content (HF) |
% |
≤0.1 |
GB/T 17650.1 / IEC 60684-2 |
| pH value |
— |
≥4.3 |
GB/T 17650.2 / IEC 60754-2 |
| Conductivity |
μS/mm |
≤10 |
GB/T 17650.2 / IEC 60754-2 |
| Chlorine content |
mg/g |
≤1.0 |
IEC 60754-3 |
| Fluorine content |
mg/g |
≤1.0 |
IEC 60754-3 |
| Bromine content |
mg/g |
≤1.0 |
IEC 60754-3 |
| Iodine content |
mg/g |
≤1.0 |
IEC 60754-3 |
6.2 Low Smoke Performance (GB/T 17651 / IEC 61034)
| Specimen Diameter d (mm) |
Number of Specimens |
Min Transmittance (%) |
| d > 40 |
1 |
60 |
| 20 < d ≤ 40 |
2 |
60 |
| 10 < d ≤ 20 |
3 |
60 |
| 5 < d ≤ 10 |
45/d (rounded) |
60 |
| 1 ≤ d ≤ 5 |
(45/3d)×7 (rounded) |
60 |
For cables with diameter >80 mm, the minimum transmittance result is multiplied by the factor (d/80).
6.3 Fire Resistance (GB/T 19216 / IEC 60331)
| Code |
Scope |
Test Duration |
Test Voltage |
Pass Criteria |
Test Method |
| N |
Up to 0.6/1 kV |
90 min flame + 15 min cooling |
Rated voltage |
2 A fuse intact, indicator lamp stays on |
GB/T 19216.21 |
6.4 Toxicity Criteria
| Item |
Criterion |
Standard |
| Toxicity index |
≤5 |
GB/T 19666 |
| Smoke toxicity |
Quasi-safe level 2 (ZA₂) or above |
GB/T 20285 |
| European toxicity index |
≤3 |
EN 50363 / BS 6853 |
| CO release during burning |
≤50 ppm |
— |
7. Material Properties
7.1 Comparison of Three LSZH Insulation Materials
| Property |
Polyolefin (LSZH-PO) |
XLPE (LSZH-XLPE) |
Fluoropolymer (LSZH-FEP) |
| Base material |
PE/PP + halogen-free flame retardant |
Cross-linked PE + halogen-free flame retardant |
Fluoropolymer (FEP/PTFE) |
| Long-term operating temperature |
-40°C to 70°C |
-40°C to 90°C |
-60°C to 200°C |
| Short-term overload temperature |
≤100°C |
≤130°C |
≤260°C |
| Insulation resistance |
≥10¹² Ω·cm |
≥10¹⁴ Ω·cm |
≥10¹⁵ Ω·cm |
| Dissipation factor (1 kHz) |
≤0.01 |
≤0.005 |
≤0.002 |
| Flame rating (UL94) |
V-1 |
V-0 |
V-0 |
| Self-extinguishing time |
≤30 s |
≤10 s |
≤5 s |
| Minimum smoke transmittance |
≥60% |
≥65% |
≥80% |
| Halogen release |
≤5 mg/g |
≤3 mg/g |
≤1 mg/g |
| Tensile strength |
≥12 MPa |
≥18 MPa |
≥20 MPa |
| Bending radius |
≥6D |
≥8D |
≥10D |
| Service life |
~10 years |
≥20 years |
≥25 years |
| Price (2.5 mm² copper) |
CNY 1.2–2/m |
CNY 3–5/m |
CNY 8–15/m |
7.2 Insulation Material: Cross-Linked Polyethylene (XLPE)
XLPE converts linear polyethylene molecules into a three-dimensional network structure through chemical or physical radiation cross-linking:
- Chemical cross-linking (silane): Uses silane coupling agents; cross-linked in 85±10°C warm water for 2–5 hours
- Radiation cross-linking: Uses high-energy electron beams from an electron accelerator; dose approximately 11 Mrad
Key XLPE advantages:
- Insulation resistance ≥10¹⁴ Ω·m
- Long-term operating temperature 90°C, short-circuit withstand 250°C
- Current capacity 10–15% higher than PVC cable of the same cross-section
- Excellent thermal aging performance, service life over 20 years
7.3 Sheath Material: LSZH Polyolefin
Main components:
- Base polymer: ethylene-vinyl acetate copolymer (EVA) + high-density polyethylene (HDPE)
- Flame retardants: magnesium hydroxide Mg(OH)₂, aluminum hydroxide Al(OH)₃
- Additives: coupling agents, cross-linking agents, compatibilizers, antioxidants, lubricants
- Free of: lead, cadmium and other heavy metals, and halogens
Typical formulation (by mass):
| Component |
Content |
| EVA |
~55% |
| HDPE |
~2% |
| Magnesium hydroxide |
~26% |
| Red phosphorus |
~0.5% |
| Coupling agent |
~7% |
| Cross-linking agent |
~1.0% |
| Compatibilizer |
~6% |
| Antioxidant |
~1.0% |
| Lubricant |
~1.5% |
7.4 Conductor Materials
| Conductor Type |
Standard |
Description |
| Oxygen-free copper (TU1) |
GB/T 3956 |
Copper ≥99.95%, oxygen ≤0.05%, resistivity ≤0.017241 Ω·mm²/m |
| Annealed copper (Class 2) |
IEC 60228 |
Stranded hard copper conductor (power cables) |
| Flexible copper (Class 5) |
IEC 60228 |
Fine-stranded flexible copper conductor (flexible cables) |
| Tinned copper |
ASTM B33 |
Oxidation resistant, suitable for humid/corrosive environments |
8. Construction and Specifications
8.1 Typical Cable Construction
Power cable construction (WDZ-YJY type):
1. Copper conductor
2. XLPE cross-linked polyethylene insulation
3. Halogen-free flame retardant filler
4. Low smoke zero halogen high-barrier tape
5. (Optional) Steel tape / wire armor
6. Low smoke zero halogen polyolefin sheath
8.2 Specification Range
Power cables (0.6/1 kV):
| Type |
Cores |
Nominal Cross-Section (mm²) |
| WDZ-YJY |
1 |
1.5 – 630 |
| WDZ-YJY |
2 |
1.5 – 185 |
| WDZ-YJY |
3 |
1.5 – 400 |
| WDZ-YJY23 |
4 |
1.5 – 400 |
| WDZ-YJY23 |
3+1 |
1.5 – 300 |
| WDZ-YJY33 |
3+2 |
1.5 – 300 |
| WDZ-YJY33 |
5 |
1.5 – 300 |
Building wires (450/750 V):
| Type |
Conductor |
Cross-Section (mm²) |
Operating Temp |
| WDZ-BYJ |
Solid |
1.5 – 35 |
90°C |
| WDZ-BYJR |
Stranded flexible |
1.5 – 35 |
90°C |
| WDZ-RYJS/RYY/RYYP |
Flexible / twisted |
0.5 – 6 |
90°C |
| WDZ-GYJS(F) |
Radiation cross-linked dual insulation |
1.5 – 35 |
90/105/125°C |
Control cables (450/750 V):
| Type |
Cores |
Cross-Section (mm²) |
| WDZ-KYJY/KYJYP |
2 – 61 |
0.5 – 10 |
European cables:
| Type |
Rated Voltage |
Cores |
Cross-Section (mm²) |
| H07Z1Z1H2-F |
450/750 V |
Multi-core |
0.75 – 16 |
| N2XH |
0.6/1 kV |
1 – 37 |
1.5 – 400 |
American cables:
| Type |
Rated Voltage |
Conductor Size |
| UL 3385 |
300 V |
32 – 10 AWG |
| UL 3886 |
1500 V/2000 V |
44 AWG – 2000 kcmil |
| UL 21143 |
300 V/600 V |
— |
| XHH |
600 V |
14 AWG – 2000 kcmil |
| TC-ER (UL 1277) |
600 V |
14 AWG – 2000 kcmil |
9. Test Methods and Equipment
9.1 Core Test Items
| Test Item |
Pass Criterion |
Test Method |
| Smoke density |
Transmittance ≥60% (20 min burning in 1.5 m³ chamber) |
GB/T 17651.2 / IEC 61034-2 |
| Halogen acid gas content |
HCl release ≤0.5% |
GB/T 17650.1 / IEC 60754-1 |
| pH and conductivity |
pH ≥4.3, conductivity ≤10 μS/mm |
GB/T 17650.2 / IEC 60754-2 |
| Oxygen index |
OI ≥32% |
ASTM D2863 |
| Vertical burning |
V-0 rating |
UL 94 / GB/T 18380.12 |
| Bunched cable burning |
Charred extent ≤2.5 m |
GB/T 18380.33–36 |
| Fire resistance |
Circuit integrity during 90 min flame + 15 min cooling |
GB/T 19216.21 |
| Conductor DC resistance |
Compliant with GB/T 3956 |
20°C resistance test |
| Insulation resistance |
≥20 MΩ·km |
2500 V / 5 min withstand test |
| Thermal aging |
Tensile strength change ≤±25%, elongation change ≤±25% |
135°C × 168 h |
9.2 Test Equipment
| Equipment |
Purpose |
Standard |
| Smoke density tester |
Measures transmittance change in NBS smoke chamber |
IEC 61034 / ASTM E662 |
| Halogen acid gas collection system |
Quantitative analysis of HCl/HF gas release |
IEC 60754-1 |
| Oxygen index apparatus |
Determines oxygen concentration for combustion |
ASTM D2863 |
| Horizontal/vertical burning chamber |
UL94 V-rating flame tests |
UL 94 / IEC 60332 |
| Thermogravimetric analyzer (TGA) |
Thermal decomposition analysis |
ASTM E1131 |
| Infrared thermal camera |
Temperature distribution during burning |
— |
| Gas chromatograph |
Quantitative analysis of combustion gases |
— |
| Glow wire test apparatus |
Glow-wire ignitability assessment |
IEC 60695-2-10 |
| Tensile testing machine |
Mechanical properties of insulation |
GB/T 2951.11 |
| Resistance tester |
Conductor DC resistance measurement |
GB/T 3956 |
10. Manufacturing Process
10.1 Main Production Steps
Raw material inspection → Wire drawing → Annealing → Conductor stranding → Insulation extrusion → Cross-linking
→ Cabling (filling/wrapping) → Armoring (optional) → Sheath extrusion → Cooling and sizing
→ In-line testing → Final inspection → Packaging and warehousing
10.2 Key Process Points
1. Raw materials
- Copper rod: electrolytic / oxygen-free copper rod, copper ≥99.95%, impurities and oxygen ≤0.05%
- Insulation compound: silane cross-linked polyethylene / radiation cross-linked polyolefin
- Sheath compound: low smoke zero halogen flame retardant polyolefin
2. Wire drawing
- Equipment: continuous drawing and annealing lines
- Process: multi-pass drawing to target wire diameter
- Requirement: conductor volume resistivity ≤0.017241 Ω·mm²/m at 20°C
3. Stranding
- Equipment: 1+6/500 high-speed tubular strander, 6+12+18+24/500 rigid frame strander
- Controls: wire diameter, number of strands, lay length, lay direction, compaction factor
4. Insulation extrusion
- Equipment: extruder (screw L/D ratio 20:1 or 25:1, compression ratio 2.5:1 or 2.0:1)
- Die: tubing-type die
- Temperature: 160–220°C (XLPE insulation)
- Cross-linking methods:
- Warm water cross-linking: 85±10°C water, 2–5 hours
- Radiation cross-linking: electron accelerator, dose approx. 11 Mrad
5. Cabling
- Equipment: 3+1+1/1600 cabling machine
- Controls: capstan speed, cradle speed, cabling direction, lay length, tape overlap rate
6. Sheath extrusion
- Material: low smoke zero halogen low toxicity flame retardant polyolefin (oxygen index ≥50)
- Die: semi-pressure type die
- Temperature: 100–160°C
- Requirements: uniform thickness, no bubbles, smooth surface
7. Armoring (optional)
- Steel tape armor: galvanized steel tape wrapping
- Steel wire armor: galvanized steel wire helix or braid
- Single-core cable armor must use non-magnetic material
8. Quality inspection
- In-line spark testing
- Conductor DC resistance measurement
- Insulation resistance test
- Voltage withstand test (2500 V / 5 min)
- Appearance/dimensional inspection
- Flame retardant / low smoke / halogen-free sampling tests
11. Applications
11.1 Locations Where LSZH Cables Are Required
| Sector |
Specific Scenarios |
Recommended Grade |
| Public buildings |
Hospital wards/ICU/operating rooms, schools/kindergartens, malls, exhibition halls |
WDZA / WDZB1 |
| Transportation |
Metro/light rail tunnels and cars, airport terminals, railway stations |
WDZA / NFPA 130 |
| High-rise buildings |
Office towers, residential towers, hotels (emergency lighting/fire circuits) |
WDZN-BYJ / WDZB1-YJY |
| Data centers |
Server cabinet power, control rooms, server room wiring |
WDZB1-YJY (B1 grade) |
| Industrial facilities |
Petrochemical/power plant control rooms, automated production lines |
WDZ-KYJY / N2XH |
| Underground spaces |
Underground garages, utility tunnels, cable tunnels |
WDZB-YJY22 (armored) |
| Marine & offshore |
Ship power systems, offshore platforms |
IEC 60092 series |
| Renewable energy |
Wind farms, PV plants (UV-resistant outdoor type) |
EN 50618 / PV1-F |
11.2 Selection Guide by Scenario
| Scenario |
Recommended Type |
Rationale |
| Residential/general office (normal temp) |
WDZ-BYJ / WDZC-YJY |
70–90°C rating, Category C flame retardance sufficient |
| High-rise / fire emergency |
WDZN-BYJ / WDZN-YJY |
Fire resistant, 90 min continuous power |
| Metro / tunnel / super high-rise |
WDZA-YJY / WDZB1-YJY |
Category A / B1 high flame retardance |
| Data center / server room |
WDZB1-YJY (XLPE) |
90°C rating, B1 flame retardance, low insulation loss |
| Industrial high-temperature areas |
WDZ-GYJS(F) (radiation cross-linked) |
125°C rating, aging resistant |
| Direct burial / heavy mechanical stress |
WDZB-YJY22 (steel tape armored) |
Armor protection, crush resistant |
| North America export |
UL 1277 TC-ER / XHH |
UL/CUL certified |
| Europe export |
N2XH / H07Z1Z1H2-F |
CPR/CE certified |
11.3 Regulatory Requirements
| Region |
Regulation/Standard |
Requirement |
| China |
GB 50217 |
LSZH mandatory for metro, hospitals, data centers, underground utility tunnels |
| EU |
EN 50575 (CPR) |
Construction cables must be fire-classified and CE marked |
| UK |
BS 8519 / BS 7629 |
LSZH mandatory for fire safety system cables |
| North America |
NFPA 130 / NFPA 75 |
Smoke and toxicity limits for transit / data centers |
12. Certification Systems
12.1 Major Product Certifications
| Certification |
Market |
Notes |
| CCC (China Compulsory Certification) |
China |
Mandatory for domestic sales |
| Industrial Production License |
China |
Cable manufacturing qualification |
| CE + CPR (EN 50575) |
EU |
Mandatory for construction cables in the EU |
| TUV |
Europe/International |
Third-party safety certification |
| UL / CUL |
USA/Canada |
North American market access |
| RoHS 2.0 |
EU/International |
Restriction of hazardous substances |
| REACH |
EU |
Chemical registration and evaluation |
| SAA |
Australia |
Australia/New Zealand market access |
| PSE |
Japan |
Japanese market access |
| EAC |
Russia-Belarus-Kazakhstan Customs Union |
Russian-speaking markets |
| ISO 9001 |
International |
Quality management system |
| ISO 14001 |
International |
Environmental management system |
12.2 Quick Reference by Target Market
| Target Market |
Power Cable Standard |
Control Cable Standard |
Wiring Cable Standard |
| China |
GB/T 12706.1 |
GB/T 9330 |
GB/T 5023 / JB/T 10491 |
| EU |
EN 50525 / IEC 60502-1 |
EN 50288-7 / EN 50525-3-11 |
EN 50525-3-21 |
| UK |
BS 6724 / BS 7211 |
BS 5308 |
BS 7211 |
| USA |
UL 1277 (TC-ER) / UL 44 |
UL 758 |
UL 758 / UL 1581 |
| International |
IEC 60502-1 |
IEC 60754/61034/60332 |
IEC 60228 |
13. LSZH vs PVC Comparison Summary
| Dimension |
LSZH Cable |
Conventional PVC Cable |
| Smoke emission |
Low (transmittance ≥60%) |
High (transmittance ≤30%) |
| Halogen content |
None |
Contains chlorine |
| Combustion toxicity |
Very low (CO ≤50 ppm) |
High (HCl ≥3000 ppm) |
| Corrosivity |
None |
Severe (corrodes equipment) |
| Flame retardancy |
V-0, self-extinguishing ≤10 s |
V-1, self-extinguishing ≤30 s |
| Current capacity |
10–15% higher at same size |
Standard |
| Operating temperature |
90°C (XLPE) |
70°C |
| Service life |
≥20 years |
~15 years |
| Environmental profile |
Recyclable, RoHS compliant |
Hard to degrade, polluting |
| Initial cost |
Higher (+10–25%) |
Lower |
| Life-cycle cost |
Lower (less fire damage) |
Higher (greater fire risk) |
14. Key Selling Points (For Website Promotion)
- Safe and non-toxic: Releases no toxic halogen gases when burning, transmittance ≥60%, protecting golden escape time in fires
- Eco-friendly and recyclable: Free of lead, cadmium and other heavy metals; RoHS/REACH compliant; supports green building certification
- High flame retardancy: Meets GB/T 19666 Category A and GB 31247 B1 grade; self-extinguishing, no flame propagation
- Fire-resistant assurance: Fire-resistant types maintain power for ≥90 minutes under 750°C flame, keeping fire protection systems running
- Ampacity advantage: XLPE insulation carries 10–15% more current than PVC at the same cross-section
- Long service life: Cross-linked structure resists aging; service life ≥20 years, far exceeding ordinary cables
- Full standards coverage: GB, EN/IEC and UL certified series for global export
- Multi-scenario fit: Power/control/wiring/flexible cables, 0.5–630 mm² full size range
- Low-corrosion protection: Non-corrosive combustion products protect precision equipment and reduce post-fire losses
- Low life-cycle cost: Slightly higher initial cost, but lower fire risk, less equipment damage, lower insurance premiums
15. AWG to mm² Cross-Section Conversion
| AWG |
Area (mm²) |
AWG |
Area (mm²) |
| 20 |
0.52 |
6 |
13.3 |
| 18 |
0.82 |
4 |
21.2 |
| 16 |
1.31 |
2 |
33.6 |
| 14 |
2.08 |
1 |
42.4 |
| 12 |
3.31 |
1/0 |
53.5 |
| 10 |
5.26 |
2/0 |
67.4 |
| 8 |
8.37 |
4/0 |
107.2 |
This document is compiled from public technical literature and industry standards for product website development. Actual product parameters shall be subject to test reports and certification certificates.
