VoltageBoard: Electrical Tools

VoltageBoard is a set of tools for people who work with electrical installations: electricians, technicians, students and engineers who need a number on site and want to know where it came from.

Every calculator shows its working. You get the result, the formula it used, the intermediate values with their units, and a plain sentence saying whether the result is inside the limit that applies. If a voltage drop comes out at 3.65 V, you can see it is 0.91 % of 400 V and that the lighting limit is 3 %. Nothing is a black box.

THE CALCULATORS

Voltage drop, cable size, short-circuit current, earth fault loop impedance, cable weight, conduit fill, cable tray fill, active/reactive/apparent power, power factor correction, transformer current, motor current, battery runtime, lighting (lumen method), solar string sizing, neutral current with harmonics, energy cost, protective device selectivity, motor starting voltage dip, harmonics and THD, and EV charging circuits.

Each one opens with worked examples you can load with a tap, so you can see what a sensible input looks like before you type your own. Voltage, frequency, ambient temperature, cable material and installation method are set once in Settings and used everywhere.

NAMEPLATE READER

Point the camera at a motor or transformer nameplate and the app reads the rated values off it into the calculator fields. Photos are processed on the device and are not stored or uploaded.

THEORY

24 topics, from Ohm's law to resonance and three-phase power, each with a circuit diagram, the derivation, the conditions under which the formula holds, and questions you can answer to check yourself. This is the part of the app meant to be read, not just used.

REFERENCE

Tables and notes you would otherwise look up in a standard or a catalogue: current-carrying capacity, cable colours, IP ratings, breaker curves, RCD types, earthing systems, disconnection times, standard voltages and more. Every table names the standard or source it was taken from, with the edition.

PROJECTS

Describe a distribution board once, then add circuits one at a time. For each circuit the app sizes the conductor, picks the protective device and checks the voltage drop against the board's supply. Pro users can export the whole schedule as a PDF.

FORUM

A place to ask other people in the trade. Reading needs no account; posting does. You can report and block.

OFFLINE, AND IN 12 LANGUAGES

Everything except the forum works with no connection. The app is available in English, Turkish, German, Spanish, French, Italian, Dutch, Polish, Portuguese, Russian, Indonesian and Vietnamese, and the language can be changed inside the app.

WHAT COSTS MONEY

The calculators, the reference tables, the glossary, most of the theory and the forum are free with no adverts. VoltageBoard Pro is a single one-time purchase, not a subscription. It unlocks PDF export of any calculation and of a project schedule, and the advanced theory topics.

PRIVACY

There is no analytics, no advertising and no tracking. Nothing you type into a calculator leaves your phone. The only data the app sends anywhere is what you post to the forum, and error reports you choose to send.

A WORD OF CAUTION

The content and the app were produced with the help of AI tools and checked by hand, but mistakes are possible. Results are for information only. Check anything you rely on against the applicable standard, and do not use this app as the basis for scientific, academic or engineering work. If you find something wrong, every page has a button to tell us.