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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.