Cable Sizing
Power cable sizing calculations ensure that medium-voltage and low-voltage underground cables operate reliably without thermal breakdown, excessive voltage drop, or short-circuit thermal damage. MEPCO calculates cable conductor sizes in accordance with IEC 60287, IEC 60364-5-52, and IEEE standards, accounting for soil thermal resistivity, grouping derating, and installation methods.
Figure 1: Heavy power cables installed in trenched sand bedding with verified thermal derating.
Technical Scope & Engineering Capabilities
MEPCO Engineering Projects brings specialized domain knowledge, rigorous modeling standards, and practical site experience to every assignment. Our scope covers:
- Continuous Current Carrying Capacity (Ampacity): Calculating base ampacity and applying derating factors for ambient temperature, grouping, burial depth, and soil thermal resistivity.
- Steady-State Voltage Drop: Verifying voltage drop limits along feeder runs under full continuous operating load.
- Motor Starting Voltage Drop: Calculating dynamic voltage dip along cable conductors during motor acceleration to verify minimum motor terminal starting voltage.
- Short-Circuit Thermal Withstand: Sizing cable phase and neutral conductors against adiabatic and non-adiabatic short-circuit temperature rise.
- Metallic Sheath / Screen Sizing: Sizing copper wire or tape screens to carry earth fault currents without exceeding insulation damage limits.
- Underground Duct Bank Thermal Modeling: Analyzing mutual heating in grouped underground cable ducts and backfill materials.
Software Platforms & Computational Tools
Primary Tool: ETAP Underground Cable Sizing & Thermal Analysis Module.
Standards Solvers: IEC 60287 rigorous thermal solver and IEC 60364-5-52 tabulated rating calculators.
Applicable Standards & Grid Codes
Thermal Sizing: IEC 60287 (Electric cables – Calculation of the current rating), IEC 60364-5-52.
Short-Circuit Withstand: IEC 60949 (Calculation of thermally permissible short-circuit currents), IEEE 399.
Methodology & Project Delivery Workflow
Our engineering delivery aligns with MEPCO’s structured 6-stage project execution framework, ensuring quality throughout input verification, design modeling, and client handover:
- Stage 01 — Scope & Criteria Definition: Establish study boundaries, utility tie-in data, single-line diagrams, and client objectives.
- Stage 02 — Data Audit & Modeling Assumptions: Collect, verify, and validate manufacturer datasheets, impedance tolerances, and site operating configurations.
- Stage 03 — Simulation Model Development: Build detailed, validated mathematical digital models in specialized power software.
- Stage 04 — Computational Analysis & Verification: Execute base-case and contingency scenarios, conducting rigorous internal peer reviews.
- Stage 05 — Client Review & Approval: Present study findings, address technical comments, and participate in technical clarification sessions.
- Stage 06 — Final Handover: Deliver formal certified engineering reports, executive summaries, and native simulation model files.
Figure 2: Medium-voltage cable terminations verified for short-circuit withstand and thermal capacity.
Completed Project References (From MEPCO Profile)
Selected project assignments delivered by MEPCO demonstrating our technical execution and regional client trust:
| Project Name | Client / Authority | Location | Tools / Mode | Scope Executed |
|---|---|---|---|---|
| Lekela 250 MW Wind Farm Project | Egyptian Electricity Transmission Company (EETC) | Egypt | ETAP | MV Collector Cable Sizing Calculations, Ampacity Derating, and Voltage Drop Analysis. |
| Municipal Infrastructure Networks | Housing & Military Engineering Authorities | Egypt | ETAP | Underground Distribution Feeder Cable Sizing and Short-Circuit Verification. |
Key Engineering Deliverables & Outputs:
- Comprehensive Cable Sizing Engineering Report detailing calculations across all feeders.
- Consolidated Cable Schedule including conductor cross-sections, insulation types, lengths, and derated ampacities.
- Voltage Drop Summary Tables under normal and motor starting conditions.
- Short-Circuit Thermal Withstand Calculation Sheets.
- Native ETAP study model file.
Inquire About This Service
Contact MEPCO’s engineering team for technical proposals, study scope definition, or project consultations:
Email: m.khaled@mepco-tds.com | Phone: +20 11 2696 7082 | HQ: 5 Al-Ibrahimia Street, Cairo, Egypt