A direct-burial power cable is selected for the conditions it will face below ground, not by a cable name alone. Electrical duty, soil thermal behaviour, water exposure, mechanical risk, installation method, and project requirements all affect the final construction. At GENGU CABLE, we work with project teams to develop power-cable proposals for underground routes.
Quick Takeaway: If you have a cable specification, send it with the route and installation details. If the project is still being developed, provide the electrical duty, ground conditions, mechanical risks, applicable requirements, and documentation needed for approval. We will review the information and prepare a cable proposal and quotation for your team’s evaluation.
1. Confirm the Installation Route
Direct burial means placing cable in an excavated trench and completing the installation with appropriate bedding, backfill, and route protection. It does not mean that every metre of the route uses the same installation arrangement.
A buried circuit may pass through open ground, wet areas, road crossings, building entries, rail crossings, or congested utility corridors. These conditions should be established before the cable construction is finalised.
Confirm:
- Soil type, stone content, and backfill material
- Groundwater level, drainage conditions, and flood exposure
- Chemical exposure from soil, hydrocarbons, salts, or industrial activity
- Road crossings, vehicle loads, and future excavation risk
- Nearby power circuits, pipelines, and underground services
- Pulling length, bends, joint bays, and maintenance access
The route determines whether the cable needs enhanced sheath performance, water protection, armor, local mechanical protection, or a combination of these measures.
2. Confirm the Electrical and Thermal Duty
The electrical design provides the basis for conductor size, insulation system, cable configuration, metallic components, and test scope.
Include the following in the project requirement:
- System voltage and frequency
- AC or DC service
- Continuous load and expected load profile
- Route length and allowable voltage drop
- Short-circuit level and duration
- Earthing arrangement
- Single-core or multicore configuration
- Number and spacing of circuits
- Future load-growth allowance
For direct-buried circuits, conductor size alone does not establish the final current rating. Soil thermal resistivity, ground temperature, burial depth, backfill, circuit spacing, the number of loaded circuits, and load profile all affect heat dissipation and cable ampacity.
Where a circuit will operate close to its thermal limit, site-specific soil data is preferable to a generic assumption. Cable heating can cause moisture migration and soil dry-out around the route, significantly reducing heat dissipation over time.
Final cable sizing, route design, burial depth, thermal calculations, bonding and earthing design, and code compliance should be confirmed by the project engineer and the relevant authority.
3. Match the Cable Construction to the Route
Conductor and Insulation System
Select conductor material and cross-sectional area for the electrical duty, termination arrangement, installation constraints, applicable requirements, and project priorities. The insulation system must suit the required voltage designation and operating conditions.
XLPE is widely used in power-cable systems. In typical XLPE cable designs, the maximum continuous conductor temperature is 90°C; comparable PVC-insulated designs are commonly based on a 70°C limit.
For applicable medium-voltage and high-voltage XLPE cables, long-term electrical performance depends on properly controlled conductor-screen, insulation, and insulation-screen interfaces, together with the required routine tests.
Water Protection and Outer Sheath
For applicable underground XLPE cable systems, wet soil, poor drainage, high groundwater, flood exposure, or a risk of sheath damage may justify additional water protection.
Depending on the route and project requirements, the construction may include:
- Moisture-resistant outer sheaths
- Longitudinal water-blocking tapes, yarns, or powders
- A radial moisture barrier
- Water-resistant conductor or metallic-screen arrangements
PE and HDPE sheaths are commonly selected where the route calls for enhanced resistance to moisture or particular soil chemicals. The final sheath material should be selected against the project environment and applicable requirements.
Water protection does not replace correct trench preparation, bedding, backfill, or route protection. It is one part of the overall cable system.
Armor and Mechanical Protection
Armor can protect against crushing, impact, tensile force, stones, and accidental external damage. Depending on the project, protection may involve steel tape armor, steel wire armor, aluminum wire armor, local civil protection, or a combination of these measures.
The right approach depends on:
- Single-core or multicore cable construction
- Pulling forces during installation
- Soil, stone content, and backfill control
- Road crossings and external-load exposure
- Required bending radius
- AC-system magnetic considerations
For single-core AC circuits, do not use steel wire armor (SWA). Where armor is required, use a non-magnetic solution such as aluminum wire armor (AWA) to avoid induced heating and magnetic losses.
Cable construction, trench preparation, bedding, backfill, route protection, pulling procedures, joints, terminations, and grounding components should be considered as one installation system.
4. Confirm Project Requirements and Documentation
Identify the project specification, owner or utility requirements, local installation rules, market approvals, and test requirements before finalising a quotation. These documents serve different purposes and should not be treated as interchangeable.
State the following where applicable:
- Required cable standard and edition
- Required market approvals or listings
- Installation and route-protection requirements
- Flame-retardant, fire-resistant, low-smoke, or halogen requirements
- Environmental-resistance requirements, such as moisture, chemical exposure, rodents, or termites, where relevant to the route
- Water-blocking or moisture-barrier requirements
- Type-test, routine-test, inspection, and traceability requirements
- Drum length, packing, delivery location, and delivery date
The required evidence should match the cable actually offered, including its construction, voltage designation, conductor-size range, and applicable requirement.
5. Prepare a Complete RFQ
A complete request reduces clarification cycles and makes technical and commercial quotations easier to compare.
| Information | What to provide |
| Project and location | Project type, country, site conditions, and delivery destination |
| Applicable requirements | Owner, EPC, utility, local-code, approval, and cable-standard requirements |
| Electrical duty | Voltage, frequency, load, fault level, earthing, route length, and circuit arrangement |
| Installation route | Burial depth, soil, backfill, groundwater, crossings, bends, and pulling conditions |
| Construction requirements | Conductor, insulation, screens, sheath, water protection, armor, and fire performance |
| Documentation | Drawings, datasheets, test reports, inspection plan, certificates, marking, and traceability |
| Supply requirements | Quantity, drum lengths, packaging, required delivery date, and destination |
If you have a BOQ, cable schedule, tender specification, construction drawing, cable marking, or a previous supplier’s datasheet, include it with your inquiry. These documents provide a useful starting point, while the final construction must be checked against the new route and project requirements.
Request a Project Quote
At GENGU CABLE, we supply power cables for land-based grid, renewable-energy, rail, industrial, and infrastructure projects. We can work from your cable schedule, BOQ, tender specification, route drawing, existing cable reference, or project brief.
Send us the available project information. Our team will review the information provided, identify any clarification points, and prepare a project-specific quotation with the proposed cable construction and documentation scope.
Request a Project Quote for Your Direct-Burial Power Cable Requirement >>
