Mv Cable Sizing Calculation Excel May 2026

Recommendation message: "Cable size XX mm² is acceptable for continuous current, voltage drop, and short circuit conditions per IEC 60502-2 / IEC 60364-5-52." OR "Increase cable size to YY mm² – voltage drop exceeds limit." | Feature | Purpose | | :--- | :--- | | Data Validation Dropdowns | For insulation type, material, grounding, etc. | | Conditional Formatting | Turn cells RED for FAIL, GREEN for PASS. | | Named Ranges | For lookup tables (e.g., CableData , TempDerating ). | | Protection (unlocked cells only) | Prevent accidental formula deletion. | | Chart: VD vs Length | Dynamic chart showing % drop for different sizes. | | Macro (optional) | "Auto-select smallest pass size" button. | Formulas Reference (to embed in cells) | Calculation | Excel Formula Example | | :--- | :--- | | Derated ampacity | =VLOOKUP(B5,CableData,3,FALSE) * k1 * k2 * k3 * k4 | | Voltage drop % | =(SQRT(3)*I_load*Length_m/1000)*(R_ac*COSφ + X*SINφ) / (U*10) | | Short circuit min area | =(I_k * SQRT(t)) / 143 (k=143 for Cu XLPE, 94 for Al) | | Utilization | = (I_FL / parallel) / I_derated |

| Conductor (mm²) | Material | Insulation | Ampacity (Air 40°C) | Ampacity (Ground 25°C) | Resistance (DC 20°C) | Reactance (Ω/km) | Short circuit rating (kA for 1s) | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | 50 | Cu | XLPE | 185 | 170 | 0.387 | 0.098 | 6.2 | | 70 | Cu | XLPE | 235 | 215 | 0.268 | 0.092 | 8.7 | | 95 | Cu | XLPE | 285 | 260 | 0.193 | 0.087 | 11.8 | | 120 | Cu | XLPE | 330 | 300 | 0.153 | 0.083 | 15.0 | | 150 | Cu | XLPE | 375 | 340 | 0.124 | 0.080 | 18.7 | | ... | ... | ... | ... | ... | ... | ... | ... | Step 1: Current Carrying Capacity Check | Calculation | Formula / Reference | Result | | :--- | :--- | :--- | | Base ampacity (from table) | =VLOOKUP(...) | A | | Derated ampacity (Id) | = A × k1 × k2 × k3 × k4 | A | | Required load current per run | = I_FL / (No. of parallel runs) | A | | Utilization | = Required / Derated | % | | Pass/Fail | =IF(Utilization ≤ 100%,"PASS","FAIL") | | Step 2: Voltage Drop Calculation | Parameter | Value | Unit | | :--- | :--- | :--- | | Length (L) | [User input] | m | | Load current (I) | A | | | Power factor (cos φ) | [User input] | | | AC Resistance (R_ac) | = R_dc × (1+ temp coeff) | Ω/km | | Reactance (X) | from table | Ω/km | | Voltage drop (ΔV) | = √3 × I × L × (R cosφ + X sinφ) / 1000 | V | | ΔV as % of U | = (ΔV / (U×1000)) × 100 | % | | Pass/Fail (≤5% or ≤10% for motors) | Logic | | Step 3: Short Circuit Temperature Rise (Adiabatic) | Parameter | Formula | Result | | :--- | :--- | :--- | | Fault current (I_k) | from input | A | | Clearing time (t) | from input | s | | Conductor area required | = (I_k × √t) / k (k from IEC 60364-5-54) | mm² | | Selected area | from trial | mm² | | Pass/Fail | =IF(Selected ≥ Required, "PASS", "FAIL") | | Step 4: Earth Fault Loop (for solid grounding) | Parameter | Value | | :--- | :--- | | Earth fault current | A | | Armor / earth conductor resistance | Ω/km | | Loop impedance | Ω | | Touch voltage | V | | Pass/Fail (≤ 430V for 0.5s) | | Sheet 5: Summary & Report | Parameter | Value | Status | | :--- | :--- | :--- | | Selected Cable Size | [Result from Sheet 4] | | | Derated Ampacity | [Value] A | | | Load Current per run | [Value] A | PASS/FAIL | | Voltage Drop (%) | [Value] % | PASS/FAIL | | Short Circuit Withstand | [Value] mm² required | PASS/FAIL | | Final Recommendation | USE / RE-SIZE | | mv cable sizing calculation excel