33kV Cables – Medium Voltage Power Cables by Tratos

Tratos 33kV Cable Range: BS 7870, BS 6622 and IEC 60502-2

Our 33kV range is manufactured to both British Standards (BS 7870-4.10, BS 6622, BS 7835) and the international IEC 60502-2 standard, covering the 19/33 (36) kV voltage rating. In the UK, our cables carry DNO approval across all major distribution network operators, including UKPN, SSE, NGED, Northern Power Grid, Scottish Power Energy Networks, and Electricity Northwest.

The range covers single-core, three-core, and triplex formation cables with copper and aluminium conductors, and XLPE or EPR insulation and sheathing in MDPE, PVC, or Low Smoke Zero Halogen (LSZH). Standard and bespoke specifications are available. As the manufacturer — not a distributor — we have direct control over cable design, materials, and quality at every stage of production.

Contact our medium voltage specialists for cable selection guidance, specification support, or bespoke requirements.

33kV Cable Construction and Specifications

Tratos manufactures standard and bespoke 33kV cables to customer requirements. The following summarises the key construction options.

Conductors: Copper and Aluminium

Copper and aluminium conductors are available up to 1000 mm². Copper is the most widely used conductor material for 33 kV cables, offering high electrical conductivity and proven performance. Aluminium provides a cost-effective alternative, particularly suited to larger conductor cross-sections where weight is a consideration. All Tratos Class 2 stranded conductors are supplied water blocked as standard.

Insulation: XLPE and EPR

Both XLPE and EPR are cross-linked insulation materials with excellent dielectric properties, high mechanical strength, and stable performance across a wide temperature range. Both are rated at 90°C and specified in BS 6622, BS 7835, BS 7870-4.10, and IEC 60502-2. XLPE is the most widely specified insulation for 33 kV distribution cables. EPR is preferred in subsea applications and where flexibility under repeated bending is required.

Metallic Screen

Individual core screens ensure uniform electrostatic stress distribution within the insulation and provide a path for fault current. Screen configurations available from Tratos include copper wire screens, copper tape screens, and aluminium laminate tape, selected according to the applicable standard and the installation’s fault level requirements.

Assembly, Armouring and Sheath Options

• Single core unarmoured: light and flexible, for installations where mechanical protection is not required.
• Single core armoured: aluminium wire armour, for installations requiring mechanical protection.
• Three core unarmoured: individually screened cores laid up with non-hygroscopic fillers.
• Three core armoured: galvanised steel wire armour with individual or collective screen.
• Triplex formation: three individually sheathed single core cables laid up together — the standard DNO configuration in the UK and used internationally for medium voltage distribution.

Sheathing options: MDPE (preferred for direct burial and cable duct installation), PVC, and Low Smoke Zero Halogen (LSZH — required in occupied buildings, tunnels, public spaces, and other fire-sensitive environments). Radial and longitudinal water blocking is available on all constructions.

Where maximum resistance to radial water ingress is required, Tratos can supply cables with the Glover Barrier — an aluminium foil laminate bonded to an MDPE sheath.

Technical Characteristics — 33kV Cable Data

Voltage rating: Uo/U (Um) 19/33 (36) kV
Temperature rating: –20°C to +90°C (fixed); +250°C (short circuit)
Conductor sizes: 70 mm² to 1000 mm² (copper and aluminium)
Test voltage (BS 7870-4.10): 4 × Uo
Test voltage (BS 6622 / 7835): 76 kV
Min. bending radius:

• 20 × OD (BS 7870-4.10)
• 15 × OD single core / 12 × OD three core (BS 6622 / 7835)

Installation methods: Direct burial, cable duct, indoor, outdoor

For full technical specifications, conductor size tables, and current ratings, refer to our detailed product data sheets or contact our technical team.

 33kV Cable Standards: BS 7870, BS 6622, BS 7835 and IEC 60502-2

Tratos 33kV cables are manufactured to the following British and international standards. The choice of standard is determined by the buyer’s market, network operator specification, and installation requirements.

BS 7870-4.10

The primary distribution cable standard for UK DNOs. Covers single core and triplex formation cables at 19/33 (36) kV, typically with MDPE or LSZH sheathing. Specified by UKPN, SSE, NGED, Northern Power Grid, Scottish Power Energy Networks, and Electricity Northwest. Also used by Independent Distribution Network Operators (iDNOs) and contractors working on UK grid connections.

BS 6622

Armoured cables with thermosetting insulation (XLPE or EPR) for rated voltages from 3.8/6.6 kV up to 19/33 kV. Covers single core and three core constructions with aluminium or steel wire armour. Used in industrial installations, oil & gas, and other applications where robust mechanical protection is required alongside UK BS compliance.

BS 7835

The fire performance variant of BS 6622, specifying low smoke emission and halogen-free gas emission in fire. Required for installations in occupied buildings, tunnels, public transport infrastructure, and other environments where fire safety is a primary concern.

IEC 60502-2

The international equivalent standard covering power cables from 6 kV up to 30 kV, widely specified across continental Europe, the Middle East, Asia, Africa, and the Americas. The 19/33 (36) kV voltage rating in IEC 60502-2 corresponds directly to the 33kV rating used in BS standards. Tratos IEC 60502-2 cables are manufactured at our facilities in Italy, Spain, and Germany, and are supplied to grid operators, EPCs, and industrial buyers operating to international specifications worldwide.

For projects requiring compliance with multiple standards, Tratos can advise on cable selection and provide documentation supporting both BS and IEC requirements.