Comprehensive Technical Guide to International Electrotechnical Commission Standard IEC 60840 — Power Cables with Extruded Insulation and Their Accessories for Rated Voltages Above 30 kV (Um = 36 kV) Up to 150 kV (Um = 170 kV)
What is IEC 60840 Cable?
Comprehensive Technical Guide to International Electrotechnical Commission Standard IEC 60840 — Power Cables with Extruded Insulation and Their Accessories for Rated Voltages Above 30 kV (Um = 36 kV) Up to 150 kV (Um = 170 kV)
Introduction to IEC 60840 Standard
IEC 60840 is an internationally recognized standard developed by the International Electrotechnical Commission (IEC) that defines the test methods and performance requirements for high-voltage power cable systems with extruded insulation. The standard applies to systems designed for rated voltages above 30 kV (Um = 36 kV) up to and including 150 kV (Um = 170 kV), making it the essential reference for cables used in power transmission infrastructure, grid interconnections, and large-scale industrial energy networks.
The current fifth edition, IEC 60840:2020, represents a significant technical evolution from previous versions, introducing requirements for composite outdoor termination insulators, a new low smoke halogen-free oversheath material designated ST12, additional fire performance tests, and water penetration testing in conductors. The standard covers cables, accessories (joints and terminations), and complete cable systems intended for fixed installations, applicable to both single-core cables and individually screened three-core cables under typical installation and operational conditions.
IEC 60840 covers power cables with extruded insulation for primary power distribution in transmission networks. Cables manufactured to this standard are designed for fixed installations and are suitable for buried applications transporting power across extended distances. The standard excludes cables for special applications such as submarine cables, mining cables, and their associated accessories where modified tests or unique conditions may be required.
To achieve compliance with IEC 60840, cables are subject to rigorous type test sequences simulated to represent a 30-year service lifetime on cable samples of at least 1 metre. Unlike IEC 60502-2 testing for medium voltage cables, IEC 60840 applies voltage during the burner heating cycles, ensuring cables can withstand the combined thermal and electrical stresses encountered in real-world high voltage transmission applications.
IEC 60840 es una norma internacional desarrollada por la Comisión Electrotécnica Internacional (IEC) que define los métodos de ensayo y requisitos de rendimiento para sistemas de cables de alta tensión con aislamiento extruido. La norma se aplica a sistemas diseñados para tensiones nominales superiores a 30 kV (Um = 36 kV) hasta 150 kV (Um = 170 kV) inclusive.
La quinta edición actual, IEC 60840:2020, introduce requisitos para aisladores compuestos de terminaciones exteriores, un nuevo material de cubierta exterior libre de halógenos y baja emisión de humo designado ST12, pruebas adicionales de rendimiento ante fuego y pruebas de penetración de agua en conductores. La norma abarca cables, accesorios (empalmes y terminaciones) y sistemas de cables completos destinados a instalaciones fijas, tanto para cables unipolares como para cables tripolares con pantalla individual.
IEC 60840 是國際電工委員會（IEC）制定的國際認可標準，定義了擠出絕緣高壓電力電纜系統的測試方法和性能要求。該標準適用於額定電壓高於 30 kV（Um = 36 kV）至 150 kV（Um = 170 kV）的系統，是電力傳輸基礎設施、電網互連和大規模工業能源網絡所用電纜的重要參考依據。
現行第五版 IEC 60840:2020 相較於先前版本有重大技術進展，引入了複合材料戶外終端絕緣子要求、新的低煙無鹵素外護套材料（標記為 ST12）、額外的防火性能測試以及導體水滲透測試。該標準涵蓋電纜、附件（接頭和終端）以及用於固定安裝的完整電纜系統，適用於典型安裝和運行條件下的單芯電纜和獨立屏蔽三芯電纜。為達到 IEC 60840 合規性，電纜需經過嚴格的型式試驗序列，模擬至少 1 米電纜樣品的 30 年使用壽命。
Voltage Ratings & Classifications
IEC 60840 covers five primary voltage ratings for high voltage power transmission cables. The voltage designation follows the format U₀/U (Um), where U₀ is the rated power-frequency voltage between conductor and earth (or metallic screen), U is the rated voltage between conductors, and Um is the maximum voltage that can be sustained under normal operating conditions at any point in the system.
For voltages above 150 kV (Um = 170 kV) up to 500 kV (Um = 550 kV), the companion standard IEC 62067 applies. The IEC 60840 voltage range bridges the gap between medium voltage cables (covered by IEC 60502-2 up to 30 kV) and extra-high voltage transmission systems, serving as the backbone of national and regional power distribution networks.
Cable Construction & Materials
IEC 60840 high voltage cables feature a sophisticated multi-layer construction designed to manage the intense electrical stresses at transmission voltages. Each layer serves a specific purpose in ensuring safe, reliable power transmission over the cable’s 30+ year service life. The construction typically includes a conductor, conductor screen, XLPE insulation, insulation screen, metallic screen, and protective oversheath.
Insulation & Sheath Material Properties
| Material | Designation | Max. Continuous Temp. | Emergency Temp. | Short-Circuit Temp. | Application |
|---|---|---|---|---|---|
| XLPE | Cross-linked Polyethylene | 90°C | 130°C | 250°C (5s max) | Primary insulation |
| EPR | Ethylene Propylene Rubber | 90°C | 130°C | 250°C | Flexible insulation |
| HEPR | Hard Ethylene Propylene | 90°C | 130°C | 250°C | High modulus insulation |
| HDPE | High Density Polyethylene | 70°C | — | — | Outer sheath (standard) |
| MDPE | Medium Density Polyethylene | 70°C | — | — | Outer sheath (flexible) |
| ST12 (LSZH) | Low Smoke Halogen Free | 70°C | — | — | Fire-sensitive areas |
Conductor Specifications
| Parameter | Copper Conductor | Aluminium Conductor | Standard Reference |
|---|---|---|---|
| Cross-section range | 185 – 2500 mm² | 300 – 2500 mm² | IEC 60228 |
| Construction | Stranded circular or Milliken | Stranded circular or Milliken | IEC 60840 |
| Conductor class | Class 2 (stranded) | Class 2 (stranded) | IEC 60228 |
| Water blocking | Swellable powder/tape | Swellable powder/tape | IEC 60840 |
| Operating temperature | 90°C | 90°C | IEC 60840 |
| Short-circuit temperature | 250°C | 250°C | IEC 60840 |
Source: Circuit Masterclass EHV Cable Construction, Alfanar HV Cables Technical Catalogue
IEC 60840 Cable Types Comparison
The following comprehensive comparison covers the major cable types manufactured in accordance with IEC 60840, organized by conductor material, voltage rating, and sheath type. These designations follow the VDE/CENELEC nomenclature commonly used alongside IEC references in international cable specifications.
Copper Conductor High Voltage Cables
| Type Code | Insulation | Water Block | Metallic Screen | Outer Sheath | Voltage Ratings |
|---|---|---|---|---|---|
| 2XS(F)2Y | XLPE | Longitudinal (F) | Cu wire + Al tape | PE | 64/110 kV (123 kV) |
| 2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 26/45 kV (52 kV) |
| 2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 36/60 kV (72.5 kV) |
| 2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 64/110 kV (123 kV) |
| 2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 76/132 kV (145 kV) |
| 2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 26/45 kV (52 kV) |
| 2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 36/60 kV (72.5 kV) |
| 2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 64/110 kV (123 kV) |
| 2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 76/132 kV (145 kV) |
Aluminium Conductor High Voltage Cables
| Type Code | Insulation | Water Block | Metallic Screen | Outer Sheath | Voltage Ratings |
|---|---|---|---|---|---|
| A2XS(F)2Y | XLPE | Longitudinal (F) | Cu wire + Al tape | PE | 64/110 kV (123 kV) |
| A2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 26/45 kV (52 kV) |
| A2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 36/60 kV (72.5 kV) |
| A2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 64/110 kV (123 kV) |
| A2XS(FL)2Y HDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | HDPE | 76/132 kV (145 kV) |
| A2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 26/45 kV (52 kV) |
| A2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 36/60 kV (72.5 kV) |
| A2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 64/110 kV (123 kV) |
| A2XS(FL)2Y MDPE | XLPE | Long. + Radial (FL) | Cu wire + Al laminate | MDPE | 76/132 kV (145 kV) |
Type Code Designation System
| Code Element | Meaning | Options |
|---|---|---|
| Prefix (none) | Copper conductor | Default for copper |
| A | Aluminium conductor | Prefix A indicates aluminium |
| 2X | XLPE insulation | Cross-linked polyethylene |
| S | Copper wire screen | Metallic screening layer |
| (F) | Longitudinal water blocking | Swellable tapes/powders |
| (FL) | Longitudinal + Radial water blocking | Complete water sealing |
| 2Y | PE outer sheath | Polyethylene oversheath |
| HDPE | High Density Polyethylene sheath | Enhanced abrasion resistance |
| MDPE | Medium Density Polyethylene sheath | Enhanced flexibility |
Source: Eland Cables IEC 60840 Products, ZMS IEC 60840 Cable
Test Requirements & Compliance
IEC 60840 specifies comprehensive test requirements to ensure cable systems meet the demanding performance standards for high voltage transmission. The testing regime includes routine tests performed on every manufactured cable length, sample tests on representative samples, type tests to verify design compliance, and prequalification tests to demonstrate long-term reliability.
Test Categories
| Test Category | Purpose | Frequency | Key Tests |
|---|---|---|---|
| Routine Tests | Production quality verification | Every cable length | Partial discharge, voltage test, conductor resistance |
| Sample Tests | Material compliance verification | Per batch/lot | Hot set test, thickness measurement, capacitance |
| Type Tests | Design validation (30-year simulation) | Initial + changes | Bending test, heating cycle, lightning impulse, water penetration |
| Prequalification Tests | Long-term reliability demonstration | New designs | Extended heating cycles, high electrical stress validation |
IEC 60840:2020 Technical Updates
| Update Area | Description | Reference |
|---|---|---|
| Gas-immersed terminations | Required to meet IEC 62271-209 for voltages above 52 kV | IEC 62271-209 |
| Composite insulators | New requirements for composite outdoor termination insulators | IEC 60840:2020 |
| Bending test cylinders | Modified diameters per IEC TR 61901:2016 | IEC TR 61901 |
| ST12 oversheath | New low smoke halogen-free material designation | IEC 60840:2020 |
| Fire performance tests | Vertical flame spread, smoke density, acidity, conductivity | IEC 60332 |
| Water penetration test | New test for water ingress into conductor | IEC 60840:2020 |
| Screen sectionalizing | Type tests on joint screen sectionalizing insulation | IEC 60840:2020 |
Source: IEC 60840:2020 Standard Document, Document Center IEC 60840
Applications & Installation
IEC 60840 cables are designed for fixed installations in high voltage power transmission networks, serving as the primary means of distributing electrical power over extended distances. These cables are suitable for both underground buried installations and overhead line applications where robustly sheathed.
| Application | Recommended Cable Types | Voltage Range | Key Requirements |
|---|---|---|---|
| Grid Transmission | 2XS(FL)2Y, A2XS(FL)2Y | 64/110 – 87/150 kV | High current capacity, FL water blocking |
| Direct Burial | 2XS(FL)2Y HDPE, A2XS(FL)2Y HDPE | 26/45 – 76/132 kV | HDPE sheath, complete water blocking |
| Cable Tunnels | ST12 (LSZH) variants | All voltages | Low smoke, halogen-free sheath |
| Substation Links | 2XS(F)2Y, A2XS(F)2Y | 64/110 kV | Longitudinal water blocking |
| Industrial Plants | 2XS(FL)2Y MDPE | 36/60 – 64/110 kV | MDPE for flexibility |
| Renewable Energy | A2XS(FL)2Y HDPE | 26/45 – 76/132 kV | Al conductor for cost efficiency |
IEC 60840 does not extend to special applications such as submarine cables and their associated accessories, mining cables, or installations where modified tests or unique conditions may be required. For such applications, specific standards like IEC 63026 (submarine power cables) should be referenced, or cables should be specified as manufactured “generally to IEC 60840” with additional project-specific requirements.
Source: Tratos Group IEC 60840 Applications, Power and Cables IEC 60840
📚 Authoritative References & Standards
- IEC 60840:2020 — Power cables 30kV to 150kV with extruded insulation | IEC Standard Document
- IEC 60840 Overview — High voltage cable standard guide | Eland Cables
- Tratos IEC 60840 — Standard scope and applications | Tratos Group
- IEC 62067 — Cables above 150kV up to 500kV (companion standard) | Document Center
- IEC 60228 — Conductor specifications for cables | ZMS Cable
- EHV XLPE Cable Construction — Technical construction guide | Circuit Masterclass
- Alfanar HV Cables — Technical catalogue | Alfanar
- Power & Cables IEC 60840 — Standards and accessories guide | Power and Cables
Contact Anhui Feichun Special Cable
For technical inquiries regarding IEC 60840 high voltage power cables, XLPE insulated transmission cable specifications, or quotation requests for power grid and industrial transmission projects, please contact our engineering team.
