🔧 Huanghe Cable | Products & Technical Guides | Underground Armoured Power Cable | Power Cable Procurement
⏱️ Estimated reading time: 17 minutes
Ordering an underground armoured power cable is more complicated than specifying a voltage rating and cable size. For an accurate quotation and a technically suitable cable, the manufacturer needs to understand the complete cable construction, electrical requirements, installation conditions and applicable standards.
This is particularly important for projects where cables will be installed by direct burial, inside ducts, in cable trenches or in other underground systems. The same conductor size may have different design considerations depending on how and where the cable will be installed.
For procurement teams, an incomplete cable specification can also create another problem: different manufacturers may quote technically different cables. A lower price does not necessarily mean a better commercial offer if the proposed cable construction does not match the project requirement.
This guide explains the 10 details to confirm before ordering underground armoured power cables. It is written for electrical engineers, EPC contractors, project procurement teams, distributors and contractors who need to prepare a clear cable specification or request quotations from manufacturers.
The objective is simple: give the cable manufacturer enough information to understand the application, provide a comparable quotation and manufacture the cable according to the agreed technical requirements.
| Specification Parameter | Standard Options & Standards | Critical Engineering Risk if Omitted |
|---|---|---|
| 1. Voltage Rating | LV (0.6/1kV) or MV (6/10kV to 18/30kV) per IEC 60502 | Insulation breakdown under system overvoltage |
| 2. Core Configuration | Single-core vs Multicore (3-core, 4-core, 3+1, etc.) | Incorrect grounding and higher installation spacing cost |
| 3. Conductor Type | Copper (Cu) or Aluminium (Al) Class 2 stranded (IEC 60228) | Inadequate ampacity leading to conductor overheating |
| 4. Armour Type | SWA (Steel Wire), STA/DSTA (Tape), or AWA (Aluminium Wire) | Eddy current losses if ferromagnetic armour is used on 1-core AC |
| 5. Underground Method | Direct burial, underground duct/pipe, or concrete trench | Derating factor misalignment causing premature insulation aging |
The first item in an underground armoured power cable specification should be the required voltage rating. The cable voltage designation needs to be compatible with the electrical system and the applicable project standard.
For low-voltage distribution, a common cable designation is 0.6/1kV. Medium-voltage systems use different voltage levels, such as 3.6/6kV, 6/10kV, 8.7/15kV, 12/20kV or other ratings depending on the electrical network and applicable standard.
The exact designation should not be selected simply because it appears frequently in a supplier catalogue. The project electrical system, equipment ratings and applicable standard should determine the required cable voltage.
Voltage rating affects more than the number printed in the cable description. It can influence the insulation system, insulation thickness, screening requirements, testing and overall cable construction.
This becomes particularly important when purchasing medium-voltage armoured power cables. According to IEC 60502-2 and Huanghe Cable engineering standards, medium-voltage underground cables require an integrated triple-extrusion screening system (conductor screen, high-grade XLPE insulation, and an insulation screen) along with a metallic screen (copper tape or copper wires) to control radial electrical stress and safely carry capacitive charging currents and fault currents.
Procurement check: Do not write only “MV armoured cable” in an RFQ. State the required system voltage and cable voltage designation whenever the project specification has already defined them.
The second important detail is the number of cores. Depending on the electrical system and application, an underground power cable may be specified as single-core or multicore.
Typical low-voltage configurations can include 1-core, 2-core, 3-core, 4-core and 5-core cables. The appropriate arrangement depends on the distribution system, earthing arrangement, neutral requirements and project design.
For medium-voltage systems, single-core cables are commonly used in applications where the three phases are installed as separate cables. Multicore constructions may also be used depending on the system design and applicable cable specification.
The number of cores should be determined by the electrical system rather than by a general preference for a particular cable construction.
For example, changing from a multicore cable to several single-core cables can affect installation arrangement, cable spacing, current-carrying capacity, termination requirements and installation cost. These factors should be considered together.
For procurement, the safest approach is to state the required number of cores clearly in the RFQ and provide the relevant single-line diagram or project specification when available.
Conductor selection is one of the most important parts of an armoured power cable specification. The two common conductor materials are copper and aluminum, and both are widely used in power distribution applications.
The required conductor cross-section should be based on the electrical design rather than selected solely from a standard catalogue size. Depending on the project, the calculation may need to consider continuous current, voltage drop, installation conditions, ambient temperature and short-circuit requirements.
Copper has higher electrical conductivity than aluminum, which means a copper conductor can achieve a required electrical performance with a different cross-section from an aluminum conductor. Aluminum, however, has a lower density and is widely used where its electrical and economic characteristics suit the project.
For large cable projects, conductor material can have a substantial effect on the overall cable weight, dimensions, transportation and material cost. Therefore, a quotation should clearly state whether the proposed cable uses copper or aluminum conductors.
A common procurement mistake is to compare two quotations based only on conductor cross-section. For example, a lower-priced 240mm² cable is not necessarily equivalent to another 240mm² cable if the conductor material, construction, insulation, armour or sheath differs.
When comparing quotations, confirm the complete cable construction before comparing the unit price.
After defining the conductor, the insulation system needs to be specified. For many power cable applications, XLPE and PVC are the two insulation materials most commonly considered.
The appropriate material depends on the cable voltage, operating conditions, applicable standard and project specification. It should not be selected solely according to the lowest material cost.
XLPE is widely used in low-voltage and medium-voltage power cable systems where its electrical and thermal characteristics are appropriate for the application. PVC is also widely used, particularly in suitable low-voltage cable constructions.
If the engineering team has already completed the insulation selection, the RFQ should state it clearly. If the insulation material has not yet been finalized, the manufacturer should be given enough information about the operating conditions to recommend a suitable construction.
Related engineering question: If your project is still deciding between XLPE and PVC, see our guide on XLPE vs PVC power cable selection for a more detailed comparison of thermal and application considerations.
The word “armoured” does not by itself define the complete construction of an underground armoured power cable. The armour type needs to be considered according to the cable design, number of cores, mechanical protection requirements and applicable standard.
Common cable armour constructions include steel wire armour (SWA), aluminum wire armour (AWA) and certain steel tape or other metallic armour arrangements used for specific cable designs.
The appropriate armour construction is not determined simply by whether a cable is installed underground. Engineers should consider the required mechanical protection, cable construction, electrical characteristics and the project specification.
While metallic armour (such as SWA) can contribute to the earth fault loop path, it should not be automatically assumed to serve as the sole protective earth (PE) conductor, especially for high fault-current or medium-voltage applications. System designers must verify whether an independent earth core or separate protective conductor is required to satisfy short-circuit loop impedance and safety standards.
For this reason, procurement teams should avoid writing only “armoured cable required” without further technical information when the project specification has already defined the armour construction.
For multicore low-voltage cables, SWA is a common construction in many markets. For single-core AC cables, non-magnetic armouring (such as Aluminium Wire Armour – AWA) must be specified instead of Steel Wire Armour (SWA). Using ferromagnetic materials (like steel) on single-core AC conductors creates alternating magnetic fields that lead to severe eddy currents, excessive hysteresis losses, and dangerous overheating of the cable.
The outer sheath is the final protective layer of an underground armoured power cable. It protects the cable construction from the surrounding environment and should therefore be selected according to the actual installation conditions rather than treated as a secondary specification.
For many standard power cable applications, PVC is used as the outer sheath material. Other sheath materials, including PE or low-smoke zero-halogen compounds, may be specified when the project requires particular environmental, fire or installation characteristics.
The correct sheath specification depends on factors such as moisture, UV exposure, mechanical conditions, chemical exposure, installation location and applicable project requirements.
A cable intended for direct burial may be exposed to moisture, soil movement, mechanical stress and other environmental conditions for many years. The complete cable construction should therefore be considered, including the conductor, insulation, metallic components and outer sheath.
This does not mean that every underground installation requires a special sheath. The correct approach is to identify the actual site conditions and then confirm whether the proposed cable construction meets the relevant requirements.
When the project has a specific sheath requirement, include it directly in the RFQ. This prevents suppliers from making different assumptions and makes the resulting quotations easier to compare.
One of the most frequently overlooked details in an underground cable specification is the actual installation method. Telling a manufacturer that the cable will be installed “underground” is useful, but it may not provide enough information for a proper engineering assessment.
Underground cables may be installed by direct burial, in ducts, in cable trenches or in other engineered underground systems. These arrangements can create different thermal and mechanical conditions.
With direct burial, the cable is installed directly in the ground according to the project’s trench, bedding, depth and protection requirements.
Soil thermal performance is critical for continuous load calculation. Beyond burial depth and cable spacing, buyers and engineers must specify the Soil Thermal Resistivity (typically expressed in K·m/W) and maximum ground ambient temperature. High soil thermal resistivity significantly restricts heat dissipation, requiring substantial derating of the conductor ampacity. If the cable is part of a larger underground network, the spacing between circuits should also be considered.
Cables installed in ducts have different heat-transfer conditions from cables installed directly in soil. The duct material, number of cables, spacing and surrounding conditions may all influence the thermal calculation.
A cable supplier should therefore know when the cable will be installed in ducts, particularly when the manufacturer is being asked to confirm current-carrying capacity or recommend a conductor size.
Where several power circuits are installed in the same trench or underground system, the thermal interaction between circuits can affect the allowable current. The number of circuits and their relative spacing should therefore be included in the engineering information provided to the cable manufacturer.
Procurement check: Instead of writing only “for underground use,” specify whether the cable will be installed by direct burial, duct, trench or another method. If available, provide the installation depth, number of circuits and approximate cable spacing.
Selecting the conductor size is not simply a matter of matching the cable to the connected load. For an underground armoured power cable, the electrical design may need to consider continuous current, voltage drop, short-circuit withstand and the actual installation conditions.
The cable must be capable of carrying the required load under the specified installation conditions. The allowable current is influenced by the conductor, insulation system and the surrounding thermal environment.
For underground installations, soil thermal resistivity, burial depth, cable spacing and grouping can become important factors. The cable size should therefore not be selected from a catalogue current rating without checking whether the rating applies to the project’s actual installation conditions.
For longer cable runs, voltage drop can become an important design consideration. A conductor with sufficient ampacity may still require a larger cross-section if the project has a specific voltage-drop limit.
This is particularly relevant to long underground feeders connecting substations, distribution equipment, industrial facilities or remote loads.
The conductor and relevant metallic components may also need to withstand the thermal and mechanical effects associated with a short circuit for the specified fault-clearing time.
The required short-circuit withstand should be confirmed against the project protection design and applicable cable standard. For medium-voltage cables, the metallic screen or other metallic components may also have specific fault-current requirements.
Cable length is a commercial specification, but it also has a direct relationship with installation planning. When ordering an underground armoured power cable, the buyer should provide both the total required quantity and, where relevant, the preferred cable length per drum.
For example, a project may require several kilometres of cable but have a preferred maximum drum length because of transportation restrictions, pulling equipment or the planned position of cable joints.
Drum length can affect the number of cable joints, installation planning, transportation and handling. A quotation that assumes a different drum length from the project requirement may therefore create additional work later.
However, the maximum practical drum length depends on the cable’s construction, outside diameter, weight, drum dimensions, transportation method and manufacturer capability. It should be confirmed with the supplier rather than assumed in advance.
For large infrastructure projects, it is also useful to provide the cable route or installation schedule when requesting a quotation. This gives the manufacturer a better understanding of the required delivery arrangement.
The final part of an armoured cable specification is the applicable standard and required documentation. This is particularly important when quotations are being requested from manufacturers in different countries.
For many power cable applications, the project may specify an IEC standard or another recognized national or project-specific standard. The exact standard should be confirmed according to the voltage level, cable construction and intended application.
For example, IEC 60502-1 covers power cables with extruded insulation for rated voltages of 1kV and 3kV, while IEC 60502-2 covers cables with extruded insulation for rated voltages above 1kV up to and including 30kV in the scope defined by the standard.
The standard should therefore be stated clearly in the RFQ rather than leaving the manufacturer to decide which standard to apply.
The project may require routine tests, test reports, certificates or other manufacturing documentation. The exact requirements should be agreed before production begins.
Depending on the project and applicable standard, buyers may request documentation such as factory test reports, certificates of conformity, technical datasheets, inspection records and packing information.
Where a project requires third-party inspection, this should also be communicated during the quotation stage. The inspection organization, inspection scope and timing should be agreed between the buyer, manufacturer and relevant project parties.
Important: Avoid asking several manufacturers to quote “according to IEC” without specifying the relevant cable standard. A clear standard reference helps ensure that the quotations are based on a comparable technical specification.
Once the technical requirements have been confirmed, the next step is to prepare a clear request for quotation. A well-structured underground armoured cable RFQ reduces unnecessary clarification between the buyer and manufacturer and makes it easier to compare quotations on the same technical basis.
The following checklist can be used as a practical starting point. Not every project will require every item, but the more complete the information is, the less room there is for different suppliers to make different assumptions.
| RFQ Item | Information to Confirm |
|---|---|
| Cable type | Underground armoured power cable and required construction |
| Voltage rating | System voltage and required cable voltage designation |
| Number of cores | Single-core or multicore; number of cores where applicable |
| Conductor | Copper or aluminum, conductor size and required construction |
| Insulation | XLPE, PVC or other specified insulation system |
| Screen / Shield | Required metallic screen / shield or other screening /shielding arrangement, where applicable |
| Armour | SWA, AWA, steel tape or other specified armour construction |
| Outer sheath | PVC, PE, LSZH or other specified sheath material |
| Installation | Direct burial, duct, trench or other installation method |
| Electrical requirements | Load current, voltage drop and short-circuit requirements where applicable |
| Applicable standard | IEC or other project-specified standard |
| Quantity | Total required cable length |
| Drum requirement | Preferred drum length, dimensions or packaging requirements where applicable |
| Testing | Required routine tests, inspection and test documentation |
| Delivery | Destination, required delivery schedule and shipping requirements |
If some information has not yet been finalized, it is better to identify it as “to be confirmed” than to leave the requirement ambiguous. The manufacturer can then identify which parts of the cable design require clarification before issuing the final quotation.
Project: [Project name]
Cable type: [Underground armoured power cable]
Voltage rating: [Required voltage]
Number of cores: [1C / 2C / 3C / 4C / 5C]
Conductor: [Copper / Aluminum]
Conductor size: [mm²]
Insulation: [XLPE / PVC / Other]
Screen Shield (For MV Cables): [Not Required / Copper Tape Screen (CTS) / Copper Wire Screen (CWS) (area in mm2） for MV / Braided or Foil Shield for LV/VFD]
Armour: [STA / SWA for Multicore AC/DC; AWA for Single-Core AC]
Outer sheath: [PVC / PE / LSZH / Other]
Installation method: [Direct burial / Duct / Trench / Other]
Installation conditions: [Depth / grouping / relevant site information]
Quantity: [Total length]
Drum length: [Required / Preferred]
Applicable standard: [IEC / Other]
Testing: [Required tests / inspection]
Delivery destination: [Country / Port / Site]
Once the cable specification has been prepared, the next step is to find a manufacturer capable of producing the required construction consistently and providing the technical documentation needed by the project.
For buyers sourcing from overseas manufacturers, the manufacturer’s production experience, quality management, applicable certifications and ability to handle project-specific requirements can be just as important as the quoted cable price.
Huanghe Cable has been engaged in cable manufacturing since 1980. The company manufactures a range of power and electrical cables, including low-voltage and medium-voltage power cables, control cables, rubber cables, photovoltaic cables, overhead cables and building wires.
Huanghe Cable operates with a manufacturing background that dates back to 1980 and has experience supplying cables for international markets. The company supports customized cable requirements when the requested construction can be produced according to the applicable technical specification.
For projects requiring recognized standards, Huanghe Cable manufactures products according to applicable IEC requirements and has IEC/CB certification, together with relevant CCC and ISO qualifications. The company has also worked with third-party inspection requirements, including SGS factory inspection.
These qualifications should not replace the buyer’s own technical evaluation. For a project-specific order, the final cable construction, standard, testing requirements and documentation should always be confirmed before production.
Yes. Huanghe Cable can discuss customized cable constructions according to project requirements, including conductor material and size, insulation, screening, armour, sheath, drum length and specified testing or documentation requirements.
The final cable design should be confirmed against the applicable project specification, engineering requirements and manufacturing standard before an order is placed.
If your cable specification is ready, you can send the requirements directly to Huanghe Cable for review. If some technical details are still being finalized, you can also share the available project information and discuss the remaining requirements with our team.
Choose whichever contact method is most convenient:
Email: sales@huanghecables.com
Huanghe Cable — Cable Manufacturing Since 1980.
At minimum, provide the voltage rating, number of cores, conductor material, conductor size, insulation, armour, outer sheath, cable quantity and applicable standard. Installation method and electrical requirements should also be provided when they are relevant to cable sizing or construction.
Not necessarily. The need for armour depends on the project’s mechanical protection requirements, installation arrangement, applicable regulations and cable specification. An underground cable should not be specified as armoured simply because it is buried; the actual installation conditions should be evaluated.
SWA refers to steel wire armour, while AWA refers to aluminum wire armour. The appropriate construction depends on the cable design and application. For certain single-core AC cable applications, the choice of metallic armour requires particular engineering consideration because of electromagnetic effects.
If the project specification has already selected the insulation system, state it clearly in the RFQ. If it has not been finalized, provide the voltage level, operating conditions and installation requirements so that the manufacturer can evaluate an appropriate cable construction.
Drum length can affect transportation, cable handling, installation planning and the number of joints required. The practical drum length should be discussed with the manufacturer based on cable diameter, weight, drum dimensions and transportation conditions.
Yes. Huanghe Cable supports customized cable requirements subject to the applicable technical specification and manufacturing requirements. Buyers can discuss conductor material and size, insulation, screening, armour, sheath, drum length and specified testing or documentation requirements with the manufacturer before production.
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