Electrical Pro Toolkit

Twelve electrical calculators for electricians, solar installers and engineers. Built to be quick on site, and honest about what it assumes.

CABLE SIZING, DONE PROPERLY

Most voltage drop tools tell you half the story. A cable has to satisfy two independent limits: it must not drop too many volts, and it must not overheat. Electrical Pro Toolkit computes both — voltage drop across the run, and current-carrying capacity after derating for ambient temperature, circuit grouping, insulation and installation method — then sizes to whichever constraint governs and tells you which one it was.

THE TOOLS

• Voltage Drop & Cable Sizing — single-phase, three-phase and DC
• Cable Ampacity & Derating — ambient, grouping, PVC/XLPE, methods B1/B2/C/E
• Motor Sizing — full load amps and inverse-time breaker selection
• Short Circuit — available fault current at a transformer secondary
• Conduit Fill — maximum conductors for a given conduit
• Earth Conductor — protective conductor by table and adiabatic equation
• Power Factor Correction — capacitor bank sizing, with before and after
• Lighting — fixture count by the lumen method, adjustable UF and MF
• PV String Sizing — modules per string inside the inverter's DC window
• Solar Yield — monthly and yearly production estimates via PVGIS
• Battery Bank — off-grid capacity from load, autonomy and depth of discharge
• Ohm's Law — solve voltage, current, resistance and power from any two

BUILT FOR REAL WORK

Every calculator states its assumptions rather than hiding them. Where a standard method has limits — the infinite-bus assumption in short circuit, the 5-second bound on the adiabatic equation, typical utilisation factors in lighting — the app says so on screen.

Enter numbers the way your keyboard types them. Comma and point decimals both work, so 2,5 and 2.5 mean the same thing.

Works offline. Only the solar yield estimator needs a connection, to reach the PVGIS service.

No account. No sign-up.

FOUR LANGUAGES

English, Spanish, French and German, including every unit label and result note.

A NOTE ON STANDARDS

Cable sizing, ampacity and earthing follow IEC 60364 practice. Conduit fill and breaker selection follow NEC tables. Check that the convention matches your jurisdiction.

Results are estimates for planning. Verify against the applicable standard, the manufacturer's data and local regulations before installing.