Operating Current Calculator for AC Systems

Calculate AC/DC current in amps from voltage, power (watts/kW), power factor, or resistance. Supports single-phase, three-phase, and Ohm’s Law. Supports: Single-phase and three-phase systems Active power → current Apparent power → current Resistance/impedance → current Bilingual support Key Formulas Single-phase: I = P / (V × cosφ) Three-phase: I = P / (√3 × V × cosφ) Single-phase: I = S / V Three-phase: I = S / (√3 × V) Single-phase: I = V / R Three-phase: I = V / (√3 × Z) Example Three-phase system, 400V, 10kW, PF=0.85 → Current ≈ 17.5 A Typical Equipment Current Reference Equipment Power Voltage Power Factor Estimated Current Household Refrigerator 150 W 230 V 0.95 ≈ 0.69 A LED Lighting (Total Load) 200 W 230 V 0.98 ≈ 0.89 A Electric Kettle 2.2 kW 230 V 1.0 ≈ 9.6 A Air Conditioner (1.5 HP) 1.1 kW 230 V 0.85 ≈ 5.6 A Three-Phase Water Pump 7.5 kW 400 V 0.88 ≈ 12.3 A Industrial Motor (15 kW) 15 kW 400 V 0.9 ≈ 24.1 A Solar Inverter (DC Output) 5 kW 48 V — ≈ 104 A Frequently Asked Questions (FAQ) Can this calculator handle both AC and DC circuits? Yes! It supports DC (using I = P/V or I = V/R) and AC single-phase/three-phase systems (with power factor and impedance). What if I don’t know the power factor? For resistive loads (heaters, incandescent lamps), use PF = 1.0. For motors, a typical value is 0.8–0.9. You can adjust it to see how current changes. Is this suitable for motor full-load current (FLC) estimation? This tool calculates theoretical current using formulas. For NEC-compliant FLC values, refer to standard tables—but this is excellent for preliminary sizing and understanding. Why does three-phase current use √3 in the formula? In balanced three-phase systems, line voltage is √3 times the phase voltage, which reduces the current per conductor for the same power—improving efficiency. Applications Home Electrical Projects: Size breakers, wiring, and outlets based on appliance current draw. Solar & Battery Systems: Calculate DC current for inverters, charge controllers, and battery banks. Industrial Maintenance: Estimate motor or pump operating current before installation. Education & Training: Visualize how voltage, power, and power factor affect current in real time. Energy Audits: Convert equipment nameplate data (kW, V, PF) into actual current for load analysis. Who Should Use This Tool? Electrical engineers and designers Electricians and maintenance technicians Students of physics or electrical engineering DIY homeowners installing EV chargers, solar panels, or workshops Renewable energy professionals

Calculates the neutral current in a three-phase, four-wire system based on phase currents. Supports: Any three-phase current values Real-time neutral current calculation Bilingual support (Chinese/English) Key Formula I_N = √(I_A² + I_B² + I_C² - I_A×I_B - I_B×I_C - I_C×I_A) Where: I_A, I_B, I_C: Phase currents I_N: Neutral current Example Phase A: 10A, Phase B: 10A, Phase C: 5A → Neutral current ≈ 5.0A

Maximum short-circuit current

Calculate the minimum short-circuit current (fault current) at the end of a low-voltage circuit — essential for verifying protective device sensitivity and ensuring safe electrical system design. This tool helps engineers, electricians, and designers determine how much current flows during a short circuit in single-phase, two-phase, or three-phase systems using copper or aluminum conductors. Supports mm²/AWG units, meters/feet/yards length units, and parallel conductors. Key Features: Single-phase, two-phase, three-phase systems support Copper/Aluminum conductors with adjustable cross-sections mm²/AWG unit compatibility for international use Parallel conductors support for complex circuits Accurate calculations based on line resistance and reactance Formula Used The calculation is based on the following formula: I sc,min = U / (√3 × (R L + X L )) Where: U: System voltage R L : Line resistance X L : Line reactance Example For a three-phase system with a voltage of 400 V, a length of 50 m, and a copper conductor of 16 mm², the calculated minimum short-circuit current is approximately 8.5 kA. Applications Residential wiring projects: Ensuring circuit breakers can handle potential faults. Commercial buildings: Verifying protection coordination for safety compliance. Industrial installations: Designing robust electrical systems that meet rigorous standards. Educational purposes: Teaching students about electrical engineering principles and fault analysis. Frequently Asked Questions (FAQ) Q: What is a short circuit? A: A short circuit occurs when there is an abnormal low-resistance connection between two points of an electrical circuit that are normally at different voltages. Q: How do I find a short circuit? A: Use diagnostic tools like multimeters or specialized equipment to detect unusual voltage drops or high currents indicating a fault. Q: Does a short circuit always trip a breaker? A: Not necessarily. If the fault current is too low due to long wire runs or high impedance, the breaker may not trip. This is why calculating minimum fault current is crucial. Q: How to calculate current in a short circuit? A: The calculator automates this process using the standard formula provided above, taking into account system voltage, conductor material, length, and size. Why Choose Our Calculator? Our Minimum Short-Circuit Current Calculator provides accurate results for professionals needing to ensure the reliability and safety of their electrical designs. With support for multiple system types, conductor materials, and units, it’s a versatile tool for any project.