Free AI-Powered Electrical Calculators – Size Equipment & Forecast Energy Costs

Calculate DC and AC voltage from current, resistance, power, impedance, or power factor. Supports Ohm’s Law, real/reactive power, and RMS values for engineers, technicians, and students. Known Parameters Formula Circuit Type Notes Current (I), Resistance (R) V = I × R DC / AC resistive Ohm’s Law; valid for heaters, incandescent lamps Active Power (P), Current (I) V = P / I DC / AC (with real power) Ensure P is active power (W), not apparent (VA) Active Power (P), Resistance (R) V = √(P × R) DC / AC resistive Derived from P = V²/R Current (I), Impedance (Z) V = I × Z AC (inductive/capacitive) Z includes resistance + reactance; use RMS values P, I, Power Factor (PF) V = P / (I × PF) General AC PF = cosφ; critical for motors, transformers How to Choose the Right Formula Your choice depends on what you can measure or know: Working with batteries or simple electronics? Use Ohm’s Law (I and R). Reading a wattmeter or nameplate? Use V = P / I (ensure it’s active power in watts). Dealing with motors, SMPS, or fluorescent lighting? You must account for power factor or impedance—use the AC-specific rows. Why Voltage Matters in Practice Voltage Drop in Wiring Excessive drop (>3%) causes motors to overheat and lights to dim. Calculate using cable resistance and load current. Power Supply Validation A 12 V solar charge controller delivering only 10.5 V may fail to charge a lead-acid battery properly. Equipment Compatibility Applying 240 V to a 230 V-rated appliance may shorten its lifespan due to increased core losses. Key Concepts Clarified DC Circuits: Voltage is constant. Only resistance matters. AC Circuits: Voltage oscillates. What matters is the RMS value (e.g., 230 V AC means 230 V RMS, ~325 V peak). Reactive components shift current relative to voltage, requiring impedance (Z) and power factor (PF) for accurate calculation. Common Mistakes Using apparent power (S in VA) instead of active power (P in W) in V = P / I Assuming PF = 1 for non-resistive loads Ignoring that multimeters report RMS for AC by default (true for sine waves only) Applying DC formulas to variable-frequency drives or LED drivers Note: For three-phase systems, this calculator handles per-phase voltage. Total system analysis requires additional considerations (e.g., line vs. phase voltage).

Calculate voltage drop in DC and AC circuits using IEC 60364-5-52 and NEC standards. Supports wire size, length, material, temperature, and parallel conductors for engineers, electricians, and designers. Parameter Purpose Typical Values Impact on Voltage Drop Current Type DC or AC — affects resistance and reactance modeling DC, AC (50/60 Hz) AC includes inductive reactance; DC uses pure resistance Voltage Supply voltage (phase-to-neutral or phase-to-phase) 120 V, 230 V, 400 V Higher supply voltage → lower % drop for same current Load Power demand of the circuit (VA or W) 1000 VA, 5 kW Higher load → higher current → greater voltage drop Wire Size Cross-sectional area of conductor (mm² or AWG) 1 mm², 14 AWG, 6 mm² Larger size → lower resistance → less drop Phase Conductors in Parallel Number of identical conductors used in parallel 1, 2, 3 More parallel wires → reduced total resistance → lower drop Line Length One-way distance from source to load 1 m, 100 ft, 50 m Longer lines → higher resistance → more drop Conductor Material Material affecting resistivity (e.g., copper vs aluminum) Copper, Aluminum Copper has ~40% lower resistivity than aluminum Cable Type Number of conductors per cable (affects impedance) Unipolar, Bipolar, Tripolar Multi-conductor cables may have higher inductance Operating Temperature Maximum allowable temperature of insulation 70°C, 90°C, 105°C Higher temp → increased resistance → higher drop Why Voltage Drop Matters Excessive voltage drop leads to: Dim lighting — incandescent bulbs lose brightness at low voltage Motor overheating — motors draw more current to compensate, risking failure Reduced efficiency — power electronics operate outside optimal range Non-compliance — violates IEC 60364-5-52 (max 3% for lighting, 5% for other loads) Key Standards & Guidelines IEC 60364-5-52 Annex G Specifies maximum permissible voltage drop in final circuits: Lights: ≤ 3% of supply voltage Other loads: ≤ 5% Total system: ≤ 10% NEC Article 215 Requires voltage drop consideration for feeder and branch circuits: Recommended limit: 3% for feeders + 3% for branch circuits = 6% total Must be considered in design, not just troubleshooting How This Calculator Works The tool calculates voltage drop using the following principles: For DC: VD = I × R × L / 1000 (R in Ω/km, L in m) For AC: VD = √(3) × I × (R × cosφ + X × sinφ) × L / 1000 Resistance (R): R = ρ × L / A, where ρ is resistivity (Ω·mm²/m), L is length, A is cross-section Temperature correction: Resistance increases by ~0.4% per °C for copper Parallel conductors: Total resistance reduced proportionally to number of wires Common Design Mistakes Using too small wire size for long runs without checking drop Ignoring temperature effects in hot environments (e.g., motor rooms) Assuming all loads are purely resistive (ignoring PF) Not accounting for multiple conductors in parallel Applying single-phase formulas to three-phase systems incorrectly Real-World Use Cases Solar PV Systems: Ensure voltage drop from panels to inverter is within 2–3% Industrial Motors: Avoid under-voltage startup that causes high inrush current Commercial Lighting: Prevent flickering in long corridors EV Charging Stations: Verify voltage at vehicle end meets charging specs Renewable Energy Installations: Optimize cable sizing for cost and performance Note: This calculator assumes balanced three-phase loads and sinusoidal waveforms. For non-linear or unbalanced systems, consult a full-load analysis tool.

Calculate protective device ratings (circuit breakers/fuses) according to IEC 60364-4-43. Supports DC/AC, conductor derating, ambient temperature, harmonic distortion, and installation methods for engineers and electricians. Parameter Purpose Typical Values Impact on Protection Rating Current Type DC or AC — affects thermal and magnetic tripping behavior DC, AC (50/60 Hz) DC requires higher breaking capacity due to no natural current zero-crossing Voltage Supply voltage (phase-to-neutral or phase-to-phase) 230 V, 400 V, 120 V Higher voltage increases arc energy during fault — impacts breaker interrupting rating Load Continuous current demand of the circuit 10 A, 50 A, 100 A Protection device must be ≥ load current × 1.25 (for continuous loads) Power Factor Ratio of active to apparent power (cosφ) 0.8, 0.9, 1.0 Low PF increases reactive current — affects conductor heating and protection coordination Method of Installation How cables are installed (affects heat dissipation) Free air, In conduit, Underground Conduit reduces cooling → lower allowable current → affects breaker selection Ambient Temperature Temperature of surrounding environment 30°C, 40°C, 50°C Higher ambient → reduced cable ampacity → requires derating Conductor Material Material of the wire (resistivity and thermal properties) Copper, Aluminum Copper has better conductivity and thermal stability than aluminum Insulation Temperature rating of insulation material PVC (70°C), XLPE (90°C) Higher temperature rating allows higher continuous current Wire Size Cross-sectional area of conductor 1.5 mm², 6 mm², 25 mm² Larger size → higher ampacity → larger protection device possible Phase Conductors in Parallel Number of identical conductors per phase 1, 2, 3 More parallel wires → higher total current capacity → higher protection rating Circuits in Same Conduit Number of separate circuits sharing one duct 1, 2, 3, 4+ More circuits → reduced cooling → derating factor applied Total Harmonic Distortion (THD) Percentage of harmonic current (especially 3n harmonics) 5%, 10%, 20% High THD increases neutral current → may require larger neutral and protection Protection Device Type Type of protective device used Circuit-breaker, Fuse Breakers offer resettable protection; fuses are sacrificial Why Proper Protection Matters Incorrectly sized protective devices can lead to: Overheating of conductors — risk of fire and insulation degradation Frequent tripping — nuisance shutdowns in industrial processes Inadequate fault clearing — prolonged short-circuit arcs cause damage Non-compliance — violates IEC 60364-4-43 and local regulations Key Standards & Requirements IEC 60364-4-43 Defines requirements for protection against: Overload (thermal protection) Short-circuit (magnetic protection) Coordination between devices Requires that the rated current of the protection device be equal to or greater than the design current of the circuit, but not exceed the conductor's maximum allowable current. Derating Factors Applied when: Multiple circuits in one conduit High ambient temperature Cables installed in confined spaces Based on IEC 60364-5-52 Table B.52.17 and Annex G. How This Calculator Works The tool determines the required protection device rating using the following logic: Step 1: Calculate conductor’s maximum allowable current based on: Wire size Installation method Ambient temperature Number of circuits in conduit Insulation type Step 2: Apply derating factors from IEC 60364-5-52 Step 3: Determine design current (Id) = Load / (PF × √3) for three-phase Step 4: Select protection device such that: In ≥ Id (rated current ≥ design current) In ≤ Ic (rated current ≤ conductor carrying capacity) Step 5: Account for THD effects on neutral and harmonic loading Common Design Mistakes Using a 16 A breaker on a 10 mm² cable without checking derating Ignoring high ambient temperatures in motor control centers Not accounting for multiple circuits in a single conduit Assuming all loads are purely resistive (ignoring PF and harmonics) Using standard breakers for DC circuits without verifying interrupting capacity Real-World Applications Industrial Control Panels: Protect motors, drives, and PLCs Commercial Buildings: Size breakers for lighting, HVAC, and outlets Renewable Energy Systems: Protect PV inverters and battery banks Electrical Distribution Boards: Ensure coordination between upstream and downstream devices Data Centers: Handle high harmonic content from servers and UPS Note: This calculator assumes balanced three-phase systems and sinusoidal waveforms. For unbalanced or non-linear loads, consult detailed harmonic analysis tools.

Determine the minimum conduit diameter for a given cable bundle using IEC 60076 fill rules. Supports PVC, steel, and raceway types. Ensures pullability and regulatory compliance. This tool calculates the minimum required conduit external diameter to safely accommodate a cable bundle, based on the maximum allowed fill percentage for different conduit types (e.g., flexible PVC, rigid PVC, steel, or raceway). The calculation ensures cables can be easily inserted and extracted during installation and maintenance. How It Works The calculator uses the formula: Dconduit = Dcable_bundle / √(Fill Percentage) Where: Dcable_bundle = overall diameter of the cable bundle (mm) Fill Percentage = maximum allowed cross-sectional fill (e.g., 40% for 3+ cables) Dconduit = internal diameter of the conduit (mm) The result is then converted to the nearest standard external diameter based on the selected conduit type. Supported Conduit Types & Fill Limits Conduit Type Max Fill (%) – 1 Cable Max Fill (%) – 2 Cables Max Fill (%) – 3+ Cables Flexible PVC 53% 31% 40% Rigid PVC 53% 31% 40% Steel (EMT/RMC) 53% 31% 40% Raceway / Trunking — — ≤50% (typical) Note: Fill percentages are based on IEC 60364-5-52 and common international practices. Always verify local electrical codes. Why This Matters Safety: Overfilled conduits cause overheating and damage to insulation. Maintenance: Allows future cable pulling without damaging existing wires. Compliance: Meets IEC, NEC, and other national wiring regulations. Cost Efficiency: Prevents rework due to undersized conduit selection. Example Calculation If your cable bundle has an overall diameter of 20 mm and you’re installing 4 cables in rigid PVC conduit: Max fill = 40% → 0.40 Required internal diameter = 20 / √0.40 ≈ 20 / 0.632 ≈ 31.6 mm Select the next standard conduit size with internal diameter ≥ 31.6 mm (e.g., 32 mm or 40 mm external, depending on wall thickness). Frequently Asked Questions What is conduit fill percentage? It’s the maximum allowable cross-sectional area that cables can occupy inside a conduit. Higher fill increases friction and heat buildup. Can I use this for fiber optic or data cables? Yes, but note that some standards recommend lower fill rates (e.g., 30%) for delicate or high-count fiber bundles. Does the calculator account for conduit wall thickness? Yes. After computing the required internal diameter, it maps to the standard external diameter using typical wall thicknesses for each material type.