Electrical calculators
Electrical calculators for wiring, panels, and low-voltage circuits. Results are estimates: verify against the current NEC and your local code.
- Conduit Fill CalculatorAdd up the cross-sectional area of every conductor and pick the smallest conduit whose allowed fill (53%, 31%, or 40% by wire count) is at least that big.Inputs: Conduit type, Installation, Conductor size and type, group 1
- Electrical Box Fill CalculatorEach conductor, device, clamp set, and ground set takes a volume allowance from NEC Table 314.16(B); add them up and compare to the volume stamped on the box.Inputs: Conductor size, Conductors that start outside the box and end in it, Devices
- Inductive and Capacitive Reactance CalculatorInductive reactance is X_L = 2πfL and capacitive reactance is X_C = 1 ÷ (2πfC), both in ohms; they cancel at the resonant frequency.Inputs: Frequency, Inductance, Inductance unit
- Power Factor Correction CalculatorRequired capacitor kVAR = real power (kW) × (tan of the present power-factor angle − tan of the target angle).Inputs: Real power, Present power factor, Target power factor
- RC Time Constant CalculatorThe RC time constant τ equals resistance in ohms times capacitance in farads, and a capacitor reaches about 63% of full charge in one τ.Inputs: Resistance, Resistance unit, Capacitance
- RL Time Constant CalculatorThe RL time constant τ equals inductance in henries divided by resistance in ohms, and inductor current reaches about 63% of its final value in one τ.Inputs: Inductance, Inductance unit, Total series resistance
- Solar Panel and Battery Bank Sizing CalculatorArray size = daily energy use ÷ (peak sun hours × (1 − system losses)), and battery capacity = daily use × days of autonomy ÷ depth of discharge.Inputs: Daily energy use, Peak sun hours per day, System losses
- Voltage Drop CalculatorVoltage drop = 2 × K × current × one-way length ÷ circular mils for single-phase (K = 12.9 for copper, 21.2 for aluminum).Inputs: Source voltage, Load current, One-way length
In the works
- Generator sizing
- Ohm's law and power