HT/LT Cable Ampacity & Voltage Drop Screening Engine

Calculates 3-phase full load operating current, applies AC resistance and inductive reactance, and evaluates compliance against internal industrial distribution limits (feeder ≤3%, branch ≤5% per NBC 2016 SP 30).

✔ 1. Formula Verified → ⚡ 2. Engineering Screening → 📐 3. Standards Referenced (IS 7098) → ⚖ 4. Engineer Review Required

⚡ Cable Run Specifications

Load Active Power kW

System Voltage (Line-to-Line) Volts

Operating Power Factor (cos φ) Lag

One-Way Route Cable Length Meters

Select Standard Conductor Size (IS 7098) XLPE

📊 Voltage Drop Audit Sheet

IS 7098 / SP 30

Percentage Voltage Drop (%Vd)
3.22 %
Line-to-Line Drop: 13.38 V at 415 V

Operating Load Current

245.51 A

Thermal Ampacity Check

PASS (≤ 310A)

Feeder Design Criterion (≤ 3.0%)

FAIL (3.22% > 3%)

Branch Design Criterion (≤ 5.0%)

PASS (≤ 5.0%)

⚠️ Engineering Recommendation: Cable passes thermal ampacity, but exceeds the recommended 3.0% feeder limit for 180m run. Upsize to 240 mm² or run parallel cables to maintain feeder voltage within optimal 3.0% threshold.

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Governing Standards & Voltage Drop Methodology

Standards & Design Attributions

IS 7098 (Parts 1 & 2): Specifications for XLPE Insulated Cables up to 1100V and 33kV.
Design Criteria ($\le 3\%$ Feeder, $\le 5\%$ Branch): Derived from National Electrical Code of India (SP 30: 2011, Section 3), National Building Code (NBC 2016 Part 8), and IEEE Std 141.
CEA Regulation 35 Role: Governs statutory supplier grid voltage variation at consumer point of supply; the 3% and 5% limits are internal premises distribution design targets.

Governing Equations

I_load = (P_kW × 1000) / (√3 × V_L × cosφ)
V_drop = √3 × I_load × (L / 1000) × (R×cosφ + X×sinφ)
%V_drop = (V_drop / V_L) × 100

⚖ Statutory Notice & Engineering Disclaimer (Tier D Integration)

This calculation provides preliminary engineering screening. Project-specific cable procurement requires verification of site grouping derating factors ($K_{\text{group}}$), burial depth ($K_{\text{depth}}$), soil thermal resistivity ($K_{\text{soil}}$), and short-circuit thermal withstand duration ($I^2t$) per IS 7098 Appendix A.