Electrical Engineering Calculators
A set of practical engineering tools based on professional standards. The interface automatically adapts to your browser language.
🔌 Transformer & Electrical Load
Compute design loads P30/Q30/S30/I30 from equipment groups, reactive compensation capacity and transformer selection.
→📘 Power Load Calculation Book
Complete LV design-load sheet: per-group loads, simultaneity, average loads, reactive compensation and transformer selection.
→🔗 Cable Sizing & Voltage Drop
Load current, ampacity check, normal/starting voltage drop and short-circuit thermal check for LV cables.
→🌪 Motor Starting
Checks motor terminal voltage during across-the-line starting using transformer and cable voltage drop.
→⛨ Grounding (Earthing)
Vertical rod, horizontal strip and composite grid resistance, with contact & step voltage check.
→🛡 Protection Relay Setting
Overload, instantaneous and earth-fault settings and inverse-time curve trip time.
→🕳 Cable Tray Sizing
Cable tray / wireway fill calculation with standard size suggestion.
→📊 Electrical Design Data
Demand coefficients Kx, power factors, building load indices and electrical installation quotas.
→🔋 Transformer Losses
Active/reactive no-load and load losses with annual energy-loss estimate (S9-M).
→💡 Lighting Design (Illuminance)
Utilization-factor, specific power density and road lighting with a built-in lamp and room database.
→⚡ Lightning Protection
Annual expected lightning strike frequency (GB50057) and single air-rod rolling-sphere protection radius.
→⚡ Reactive Power Compensation
Load power-factor correction capacity and detuned (harmonic-tuned) filter bank sizing.
→🏗 Conductor Mechanical (Sag & Tension)
Overhead line conductor sag and tension under ice, wind and temperature using the equation of state.
→💥 Short-Circuit Current
Symmetrical and peak short-circuit current at a fault point by impedance / per-unit method.
→📐 Materials & Hardware Manual
Reference tables: steel, copper, aluminium, wires, pipes, angles and shapes with theoretical weights.
→⚡ Electrician Quick Calculator
Rated current of 3-phase motors, transformer capacity-to-current conversion and copper/aluminium busbar mass & cost.
→🔢 Current Estimation (Rule of Thumb)
Transformers, motors, capacitors and fuses: rated current by the practical field-handbook coefficients with exact formulas.
→🔵 Series Reactor (Detuning)
Capacitor-bank series reactor sizing: rated current, inductance, terminal voltage and detuning resonance check.
→🧵 Wire & Conduit Sizing
Size copper conductors in PVC/steel conduit by load current, select ground conductor and check conduit occupancy.
→🗄 Distribution Box Load Calculation
Per-circuit demand load sheet of an LV distribution panel: phase balancing, design current, conductor and breaker selection, and main infeed with simultaneity.
→🛢 Capacitor Unbalance Protection
Open-delta unbalanced voltage protection setting for wye-connected capacitor banks (external-fuse method).
→⚡ Line Voltage Drop (mV/A·m)
Voltage-loss coefficient (mV/A·m) lookup and feeder voltage drop for DC, single-phase and three-phase circuits.
→🧶 Structured Cabling Estimate
Average cable run per outlet, cables per box and total boxes required for a horizontal cabling project.
→🏃 Motor Starting Voltage Drop
Empirical bus and motor-terminal voltage drop during across-the-line starting.
→🌀 Straight Tower Swing Angle
Wind-induced swing angle of suspension insulator string on straight towers under working voltage, internal and external overvoltage.
→🔌 Transformer Protection Setting
Overcurrent and instantaneous (速断) protection trip-current setting and sensitivity check for power transformers.
→⚙ Transformer Parameters & Current
Transformer winding rated/operating current, CT selection, and reference tables for model type and standard capacity levels.
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