Oct. 14, 2026
A medium voltage unarmoured cable carries power at medium voltage without a metallic armour layer. It can be suitable for installations where the cable is supported and protected by the route design, such as ducts, cable trays, or controlled indoor environments. Selecting the right cable depends on system voltage, insulation, conductor material and size, installation conditions, fault requirements, and applicable standards. I recommend confirming these details with the project engineer and cable supplier before ordering, because an unarmoured construction is not a substitute for mechanical protection where the route is exposed to damage.
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This guide is for electrical contractors, distributors, consultants, procurement teams, and project owners evaluating medium voltage (MV) power cable. It is intended to support early product selection and supplier discussions, not replace engineering calculations or local electrical rules. Requirements can differ by country, utility, project specification, and installation environment. Confirm the final design with the responsible electrical professional.
Medium voltage unarmoured cable is an insulated power cable designed for MV distribution, but without the steel wire, steel tape, or other armour used in some cable constructions. “Unarmoured” describes the lack of that armour layer; it does not mean the cable has no outer sheath or screening. Many MV designs include a conductor screen, insulation screen, metallic screen, and protective outer sheath, with the exact construction determined by the specification.
As one standards reference, IEC 60502-2 covers extruded-insulation power cables for rated voltages from 6 kV (Um 7.2 kV) up to 30 kV (Um 36 kV). A designation such as 12/20 (24) kV identifies a cable voltage class; it should not be selected by matching only the first number to a system label. The project’s nominal voltage, highest system voltage, earthing arrangement, and applicable standard must all be considered.
MV conductors are commonly made from copper or aluminium. Copper offers higher electrical conductivity for a given cross-sectional area, while aluminium may be considered where project cost, weight, and termination requirements support its use. The conductor size must be established through load, voltage-drop, short-circuit, and installation calculations rather than a general rule of thumb.
Cross-linked polyethylene (XLPE) is a widely used MV insulation option. For many XLPE cable designs, a 90°C maximum conductor temperature is specified for normal continuous operation, but the applicable value must be verified against the product standard and datasheet. Other operating conditions, such as emergency loading and short-circuit temperature limits, are also design-specific.
MV cables commonly use semiconductive screens around the conductor and insulation to manage the electric field, along with a metallic screen that provides an electrical path for fault current and grounding as designed. The outer sheath protects the cable from environmental exposure; it does not provide the same mechanical protection as armour. Depending on the project, buyers may specify single-core or three-core construction, sheath material, fire performance, water resistance, or other properties.
Unarmoured cable can be appropriate when the cable route is enclosed or otherwise protected from impact, crushing, and other mechanical hazards. Potential applications include cable ducts, protected trenches, substations, industrial facilities, and installations on trays or supports where the design and local rules permit. Suitability depends on the actual route, access, surrounding equipment, and maintenance conditions—not simply the type of facility.
For direct-buried routes, exposed outdoor runs, or areas subject to excavation, vehicle movement, or physical impact, the project team should assess whether additional protection is necessary. That protection may be provided by the cable construction, conduit, ducting, barriers, or another engineered method. If the installation specification requires armour, an unarmoured cable should not be treated as an interchangeable option without formal approval.
Record the nominal and highest system voltage, frequency, earthing method, expected load, and fault level. Confirm the required voltage designation and the governing cable standard with the designer or utility. These inputs affect insulation selection, screen design, conductor sizing, and accessories.
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Document whether the cable will be installed in a duct, trench, tray, building, or outdoor route. Include ambient conditions, grouping with other circuits, soil conditions where relevant, exposure to water or chemicals, and potential mechanical hazards. These factors influence current-carrying capacity and the suitability of the sheath and installation method.
State conductor material and cross-sectional area, number of cores, insulation, metallic screen requirements, outer sheath, and any project-specific performance requirements. Also identify the cable length, drum or delivery constraints, and compatible termination and jointing accessories. Ask the supplier to provide the applicable technical datasheet and construction details for review.
Before installation, confirm the manufacturer’s minimum bending radius, pulling tension, sidewall pressure limits where applicable, and recommended handling conditions. These values depend on cable design and installation method, so do not apply a generic figure in place of the product instructions. Ensure the installation team has compatible tools, accessories, and the required inspection and testing plan.
Pricing for MV cable depends on voltage class, conductor material and size, core count, screen and sheath construction, specified standards, total quantity, and delivery requirements. A quote based only on “medium voltage unarmoured cable” may not be comparable with another supplier’s offer if the constructions differ. Provide a complete specification and request clarification for any deviations.
Minimum order quantity and lead time can vary with the requested design, raw material availability, production scheduling, and shipping destination. I recommend confirming these points during quotation rather than assuming a standard production window. For projects with phased deliveries or non-standard requirements, share the schedule early so the supplier can assess feasibility.
At Zhongdong Cable, we encourage buyers to share the system voltage, cable route, conductor requirements, applicable specification, quantity, and delivery destination when requesting a quotation. This information helps us review the requested construction and identify details that need confirmation. Product suitability should be assessed against the project documents and the technical information supplied for the specific cable.
A frequent mistake is choosing a cable by voltage designation alone while overlooking the installation route and mechanical risk. Another is assuming that an outer sheath makes an unarmoured cable suitable for direct burial or exposed locations without additional protection. Buyers can also overlook screen grounding, accessory compatibility, or the impact of cable grouping on ampacity.
To reduce these risks, align the purchase specification, installation design, and accessory schedule before placing an order. Ask the cable supplier to identify any missing information, and have the responsible engineer review the final datasheet. Keep the approved technical documents available to the installation and commissioning teams.
Medium voltage unarmoured cable is a viable option when its electrical construction matches the system and the route provides adequate mechanical protection. Start by confirming voltage class, load and fault requirements, installation conditions, applicable standards, and cable accessories. Then compare suppliers using a complete, like-for-like technical specification rather than price alone.
For a project-specific assessment or quotation from Zhongdong Cable, prepare your voltage designation, conductor and core requirements, installation method, applicable standard, quantity, and target delivery schedule. We can review the requested configuration and clarify the technical and commercial information needed to move your sourcing decision forward.
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