1. Introduction to 18/30kV Medium Voltage Cables

With a voltage rating of 18/30kV, these unarmoured cables with copper or aluminium conductors represent an essential category of European standard medium voltage cables. The 18/30kV rating signifies that these cables are designed for systems where the phase-to-earth voltage is 18kV and the phase-to-phase voltage is 30kV, with a maximum system voltage (Um) of 36kV. This voltage class is frequently deployed in power distribution grid networks, connecting sub-stations or feeding directly into industrial installations where transformers step down the voltage as required.

The range of 18/30kV cables is generally referenced according to their construction, with the most common cable nomenclature using the German/Austrian naming codes. In this system, N identifies copper cores and NA designates aluminium cores. These cables are manufactured in accordance with IEC 60502-2, the international standard for medium voltage cables, as well as regional standards including DIN VDE 0276-620 and HD620.

2. German/Austrian DIN VDE Cable Nomenclature

Understanding the German/Austrian naming system is essential for specifying 18/30kV cables correctly. The nomenclature follows a systematic pattern that identifies conductor material, insulation type, screening, and sheath material. This standardized approach ensures consistent specification across international projects and simplifies cross-referencing between different regional standards.

Example Cable Designations

Applying this nomenclature system, you can decode any 18/30kV cable designation. For instance, N2XS2Y indicates a copper conductor (N), XLPE insulated (2X), copper wire screened (S), with PE sheath (2Y). The aluminium equivalent would be NA2XS2Y, where the conductor is aluminium instead of copper. Adding waterblocking notation such as (F) or (FL) indicates additional moisture protection for wet installation environments.

3. PVC Sheathed 18/30kV Cables (N2XSY / NA2XSY)

The N2XSY and NA2XSY cables represent the PVC-sheathed variants of the 18/30kV medium voltage cable family. These cables feature XLPE insulation with a PVC outer sheath, making them suitable for indoor and outdoor fixed installations. The PVC sheathing provides good resistance to oils, acids, and alkalis, along with flame retardancy to IEC/EN 60332-1.

NA2XSY Aluminium Variant

The NA2XSY cable shares the same construction as the copper N2XSY but uses a Class 2 stranded aluminium conductor. This variant offers a cost-efficient alternative where space is not an issue, as aluminium cables have larger overall diameters for equivalent current-carrying capacity. The aluminium version is particularly advantageous for long cable runs where the weight saving can significantly reduce installation complexity and cost.

4. PE/MDPE Sheathed 18/30kV Cables (N2XS2Y / NA2XS2Y)

The N2XS2Y and NA2XS2Y cables feature a polyethylene outer sheath, typically medium density polyethylene (MDPE) or high density polyethylene (HDPE). This construction provides superior UV resistance and mechanical robustness compared to PVC, making these cables ideally suited for fixed outdoor installations where there may be an element of mechanical stress and sunlight exposure. The PE sheath also offers excellent moisture resistance for direct burial applications.

NA2XS2Y Aluminium PE Sheathed Cable

The NA2XS2Y is the aluminium conductor equivalent, manufactured in accordance with IEC 60502-2 and DIN EN 60228. Other than its aluminium conductor, the NA2XS2Y shares the same cable construction as its copper variant. This cable is a cost-efficient alternative on installations where space is not an issue due to the larger overall diameter of aluminium cables.

Source: Eland Cables – NA2XS2Y Cable

5. Waterblocked 18/30kV Cables — (F) and (FL) Variants

Waterblocking layers are commonly specified on 30kV cables where the installation environment may see them in cable ducts liable to flooding or in waterlogged ground. These protective measures prevent water ingress from damaging the underlying insulation and conductor, significantly extending cable service life in challenging environments. Two levels of waterblocking protection are available: longitudinal (F) and dual longitudinal plus radial (FL).

N2XS(F)2Y — Longitudinal Waterblocked Copper Cable

The N2XS(F)2Y cable incorporates longitudinal waterblocking tapes applied either side of the metallic screen. These swellable tapes expand when in contact with moisture, blocking water propagation along the cable length. This construction is also available with PVC (N2XS(F)Y) and LSZH (N2XS(F)H) sheathing options to meet different installation requirements.

NA2XS(FL)2Y — Dual Waterblocked Aluminium Cable

The NA2XS(FL)2Y provides the highest level of water protection with both longitudinal and radial waterblocking. The radial barrier consists of an aluminium/polyethylene terephthalate (Al/PET) laminate applied under the sheathing, preventing moisture from penetrating radially through the sheath. This construction is essential for cables installed in flooded cable ducts or waterlogged ground conditions.

Source: Power & Cables – NA2XS(F)2Y RM 18/30kV Cable

6. Dutch Standard YMz1Krvasdlwd 18/30kV Cables

The YMz1Krvasdlwd cables are designed specifically for the Dutch market and manufactured in accordance with HD 620-10J and NEN 3620 standards. These cables feature a distinctive red LSZH sheath and incorporate both radial and longitudinal waterblocking for comprehensive moisture protection. The Dutch nomenclature follows a different pattern from the German DIN VDE system but provides equivalent technical performance.

YMz1Krvasdlwd-AL Aluminium Variant

The YMz1Krvasdlwd-AL cable is the aluminium conductor version, available in the same 18/30kV voltage rating. This cable offers the same LSZH UV-resistant sheathing with underlying radial and longitudinal waterblocking properties, making it suitable for grid networks buried directly or in cable ducts. The aluminium variant provides significant weight savings for long cable runs while maintaining equivalent electrical performance.

Source: Eland Cables – YMz1Krvasdlwd-AL Cables

7. Portuguese Standard XHIOE/LXHIOE 18/30kV Cables

The XHIOE and LXHIOE cables use Portuguese nomenclature but are manufactured in accordance with IEC 60502-2 and HD620 international standards. These cables are designed for power transmission and distribution, supporting both grid networks and industrial equipment. The Portuguese naming system uses X to indicate copper conductor and LX for aluminium conductor, with additional codes specifying waterblocking levels.

XHIOE 18/30kV Series — Copper PE Sheathed

Source: Eland Cables – XHIOE and LXHIOE Cables

8. Technical Specifications

Comprehensive Electrical Parameters

Sources: Tratos Group – 30kV Cables, Eland Cables – Medium Voltage Cable

9. Complete 18/30kV Cable Model Comparison

10. Applications & Installation Environments

30kV medium voltage cables are typically used in large medium voltage power distribution networks, between substations, local transformer stations, and industrial installations, over transmission distances up to 30 km. Many European countries use this voltage rating, making these cables essential for international grid interconnections and cross-border power distribution projects.

Installation Methods