Advanced Cable & Wire Calculators | Earthing, Short Circuit, Tray Fill – CircuitSecrets

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CircuitSecrets Professional Electrical Engineering

PHASE 2 — ADVANCED

Cable & Wire Calculators — Phase 2

Industrial-grade cable calculations for field engineers, consultants and EPC contractors. Safety-critical sizing per international standards.

IEC 60364 IEC 60949 IEC 60287 BS 7671 NEC

🔩 Earth / Ground Wire Size Calculator

Determines the minimum protective earth (PE) conductor size per IEC 60364-5-54, Table 54.7. Used in TN, TT and IT earthing systems for equipment bonding and fault protection.

📥 Input Parameters

Phase Conductor Size 1.5 mm² 2.5 mm² 4 mm² 6 mm² 10 mm² 16 mm² 25 mm² 35 mm² 50 mm² 70 mm² 95 mm² 120 mm² 150 mm² 185 mm² 240 mm² 300 mm² 400 mm² 500 mm² 630 mm² Standard IEC cable sizes

Conductor Material Copper (Cu) Aluminium (Al)

System Earthing Type TN (TN-S / TN-C-S) TT IT

📊 Calculation Results

Phase Conductor

—

mm²

Min. Earth (PE) Size

—

mm²

Material

—

IEC 60364-5-54, Table 54.7 — PE Sizing Rule:
If S ≤ 16 mm² → PE = S
If 16 < S ≤ 35 mm² → PE = 16 mm²
If S > 35 mm² → PE = S / 2 (rounded to nearest standard size)

⚠️ Cable Short Circuit Withstand Calculator

Calculates the maximum short-circuit current a cable can withstand for a given fault duration per IEC 60949. Critical for protection coordination and cable thermal damage prevention.

📥 Input Parameters

Cable Cross-Section 1.5 mm² 2.5 mm² 4 mm² 6 mm² 10 mm² 16 mm² 25 mm² 35 mm² 50 mm² 70 mm² 95 mm² 120 mm² 150 mm² 185 mm² 240 mm² 300 mm² 400 mm² 500 mm² 630 mm²

Conductor Material Copper (Cu) Aluminium (Al)

Fault Duration Seconds (0.01 – 5 s)

Insulation Type PVC (70 °C) XLPE / EPR (90 °C)

📊 Calculation Results

Cable Size

—

mm²

Withstand Current (I_sc)

—

kA

Fault Duration

—

seconds

k Factor Used

—

IEC 60949 — Adiabatic Equation:
I = k × S / √t

Where:
  I = short-circuit withstand current (A)
  k = material/insulation constant
  S = conductor cross-section (mm²)
  t = fault duration (s)

k values:
  Cu + PVC = 115  |  Cu + XLPE = 143
  Al + PVC = 76   |  Al + XLPE = 94

🔌 Parallel Cable Sizing Calculator

Determines the number of parallel cable runs required to carry a given load current, applying a 125% safety margin per run as recommended by IEC installation practice. Ensures equal load sharing.

📥 Input Parameters

Total Load Current Amperes (A)

Single Cable Rated Capacity Amperes per cable (A)

Cable Size 25 mm² 35 mm² 50 mm² 70 mm² 95 mm² 120 mm² 150 mm² 185 mm² 240 mm² 300 mm² 400 mm² 500 mm²

Number of Parallel Runs (optional) Leave blank for auto

📊 Calculation Results

Required Parallel Cables

—

runs

Cable Size Per Run

—

mm²

Current Per Cable

—

A

Total System Capacity

—

A

Utilisation

—

%

Spare Capacity

—

A

📐 Cable Tray Fill Calculator

Checks cable tray fill ratio against the industry limit of 40% maximum fill (IEC / NEC standard). Overfilling causes heat build-up, derating and potential cable damage.

📥 Input Parameters

Tray Width mm (internal usable)

Tray Depth / Height mm (internal usable)

Number of Cables

Cable Outer Diameter mm (per cable)

📊 Calculation Results

Tray Cross-Section

—

mm²

Total Cable Area

—

mm²

Fill Percentage

—

%

Allowable Fill

40

% (IEC/NEC max)

Max Cables Allowed

—

cables

Remaining Capacity

—

cables

VISUAL FILL INDICATOR

40% limit

⚖️ Cable Weight & Cost Estimator

Estimates cable weight based on conductor material density and provides a rough cost figure for procurement planning. Uses standard densities: Copper 8,890 kg/m³, Aluminium 2,700 kg/m³.

📥 Input Parameters

Cable Cross-Section 1.5 mm² 2.5 mm² 4 mm² 6 mm² 10 mm² 16 mm² 25 mm² 35 mm² 50 mm² 70 mm² 95 mm² 120 mm² 150 mm² 185 mm² 240 mm² 300 mm² 400 mm² 500 mm² 630 mm²

Conductor Material Copper (Cu) Aluminium (Al)

Cable Length Metres (m)

Number of Cores 1 Core (1C) 2 Core (2C) 3 Core (3C) 4 Core (4C) 3C + E (3+1) 3C + N + E (5C)

Price per kg (optional) Local currency per kg

Insulation / Armour Overhead Unarmoured PVC (~30%) SWA / Armoured (~50%) Heavy Duty / LSZH (~70%) Weight factor over bare conductor

📊 Calculation Results

Conductor Weight

—

kg

Total Cable Weight

—

kg

Weight per Metre

—

kg/m

Estimated Cost

—

Cable Specification

—

Drum Weight (est.)

—

kg (cable + drum)

Weight Calculation:
Conductor Weight = Cross-section (m²) × Length (m) × Density (kg/m³) × Cores
Total Weight = Conductor Weight × Overhead Factor

Densities: Cu = 8,890 kg/m³  |  Al = 2,700 kg/m³

⚠️ Professional Disclaimer

This calculator is for estimation purposes only. Always verify with manufacturer data and local electrical codes. CircuitSecrets accepts no liability for design decisions based solely on these calculations. Engage a qualified electrical engineer for safety-critical designs.

CircuitSecrets — Cable & Wire Calculators Phase 2

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