UK Medium Voltage Cables 11Kv To 33Kv
What Is Medium Voltage Cable?
Cleveland Cable Company is the UK's largest supplier of medium voltage (MV) cables. These are electrical power cables designed to operate between low voltage (LV) distribution and high voltage (HV) transmission systems.
MV cables are used to move electrical energy in bulk between substations, between substations and large users, and within large industrial or renewable energy sites. They bridge the gap between:
- LV systems (up to 1kV): Used for final distribution to homes and small businesses.
- HV and EHV systems (above approximately 36kV): Used for long-distance transmission.
In the UK distribution network, the most common MV system voltages are 11kV, 22kV and 33kV, alongside similar intermediate voltage levels used in some legacy areas and private networks.
Standards, Construction and Selection Basics
BS 6622, BS 7835 & BS 7870
- BS 6622: Covers armoured power cables designed for medium voltage applications, typically up to 19/33 (36)kV. They are suitable for fixed installations across electricity distribution networks, power stations and industrial applications. These cables are XLPE insulated and usually feature PVC or MDPE outer sheaths.
- BS 7835: Covers medium voltage power cables featuring LSZH (Low Smoke Zero Halogen) sheaths to reduce smoke and corrosive gas emissions in the event of a fire. For increased protection against mechanical stress, these cables are armoured with either SWA (Steel Wire Armour) for multicore cables or AWA (Aluminium Wire Armour) for single-core cables.
- BS 7870: Covers medium voltage power cables, including 11kV and 33kV designs. These MV cables are typically XLPE insulated and finished with an MDPE sheath, although LSZH sheath options may also be available. They are engineered for underground and ducted power distribution in utility, industrial and infrastructure projects.
Medium Voltage Cable Construction
Typical MV cables for 11kV, 22kV and 33kV applications use similar layered construction. A common design for modern 33kV cables, also mirrored in 11kV and 22kV cables, includes:
- Conductor: Copper or aluminium conductor, stranded and often compacted.
- Conductor Screen: Extruded semiconducting layer.
- Main Insulation: XLPE (cross-linked polyethylene) insulation.
- Insulation Screen: Semiconducting layer.
- Metallic Screen: Copper wires or tape.
- Bedding and Armour: Provides mechanical protection where required. Many BS 7870 cable designs are unarmoured.
- Outer Sheath: Often MDPE (medium-density polyethylene).
The exact dimensions of each layer depend on the rated voltage. For example, 33kV cables generally require thicker insulation than equivalent 11kV designs.
Factors That Influence Voltage Choice
Choosing between 11kV, 22kV and 33kV medium voltage cables depends on several factors:
- Circuit Length and Losses: Higher voltages reduce current for the same power transfer, helping to minimise electrical losses and voltage drop.
- Power Level: Higher voltages can support greater power transfer, particularly over longer transmission distances.
- Existing Network Voltage: In the UK, distribution network operators (DNOs) largely standardise on 11kV and 33kV. Private networks may also adopt these voltage levels for compatibility.
- Future Expansion: Selecting 22kV or 33kV can provide additional capacity for future load growth or renewable generation.
From a practical standpoint, 11kV MV cables are often used where cable runs are shorter and electrical loads are moderate, while 22kV and 33kV circuits can support longer distances and higher power transfer requirements.
Our 11kV Medium Voltage Cable
11kV Medium Voltage Cable Applications
- Local Distribution Networks: Connecting primary substations to secondary substations within local electricity distribution networks.
- Industrial Plants and Large Facilities: Supplying local transformers that provide low voltage electricity for industrial plant loads.
- Renewable Energy and Substation Links: Connecting solar farms, battery energy storage systems and smaller wind projects to nearby 11kV feeders.
Our 22kV Medium Voltage Cable
22kV Medium Voltage Cable Applications
- Industrial Plants and Large Facilities: Interconnecting central substations with process-area substations over longer internal distances. These cables can also support campus-wide networks where 11kV would result in excessive current or unacceptable voltage drop.
- Renewable Energy and Substation Links: Supporting wind and solar farms extending over wider geographical areas where using 11kV cables could result in higher electrical losses.
Our 33kV Medium Voltage Cable
- BS 6622 33kV Cable
- BS 7835 33kV Cable
- BS 7870 Copper Service Cable
- BS 7870 Aluminium Renewable Cable
- SSE DNO Cable
- SPEN DNO Cable
- ENW DNO Cable
- NPG DNO Cable
- UKPN DNO Cable
- NGED DNO Cable
Typical 33kV Medium Voltage Cable Applications
- Longer Feeders and Collection Circuits in DNO Infrastructure: Connecting primary substations to higher-voltage network nodes and supporting long rural feeders where 11kV circuits could experience excessive voltage drop.
- Industrial Plants and Large Facilities: Supplying very large industrial complexes, refineries and data centres that may use 33kV internal networks, particularly where site import capacity is high.
- Renewable Energy and Substation Links: Supporting large onshore renewable energy projects across the UK, including wind farms, wind turbine collection networks and solar parks.
Overall, 11kV, 22kV and 33kV medium voltage cables each serve specific purposes in the UK and international power distribution landscape. Understanding their typical applications, construction and governing standards allows engineers and technical buyers to specify the most appropriate MV cables for reliable, efficient electrical power distribution.
Why Choose Cleveland Cable?
- UK's largest stockist of UK medium voltage cable.
- Cables for utility, industrial and infrastructure applications.
- Competitive prices with fast UK and international delivery.
- Expert technical support for power network requirements.
- In-house UKAS-accredited testing facilities supporting quality control.
- BASEC Approved where applicable.
Browse cables by type | Contact Cleveland Cable for technical advice and bulk pricing on UK Medium Voltage Cable
