Cable Size Calc — VoltPro

Cable size, voltage drop, breaker rating and electrical panel: VoltPro is the electrical calculator for electricians, built for the French NF C 15-100 standard (2024 edition) and the Belgian RGIE (Book 1). 100% offline, no ads, no account.

YOUR STANDARD, YOUR COUNTRY
Pick your standard at first launch or in the settings: NF C 15-100 or RGIE. It is pre-selected from your phone's country and shown on every screen ("NF C 15-100 · FR", "RGIE · BE"). Calculations, panel checks, guide and PDF report all follow the active standard. Interface available in Dutch for Flanders.

CABLE SIZE CALCULATOR
Pick the circuit — lighting, sockets, cooktop, oven, dishwasher, tumble dryer, water heater, EV charging point — and set the cable run length, with the slider or the keyboard: the cable cross-section, the breaker rating and the voltage drop are shown live. If the length requires an upsized cross-section, VoltPro explains why, with the reference in the standard.

VOLTAGE DROP
Voltage drop calculator in single-phase 230 V and three-phase 400 V, copper or aluminium: immediate compliance verdict (3% lighting, 5% other uses) and suggested fix.

SHORT-CIRCUIT CURRENT
End-of-line short-circuit current (conventional method) and check of the breaker's magnetic trip according to its curve (B, C or D).

ELECTRICAL PANEL: LAYOUT AND LABELS (PRO)
Build your panel rows: type A or AC RCD, circuits per RCD, spare capacity — compliance is checked live against the active standard (20% spare capacity under NF C 15-100; 30 mA type A RCDs and max 8 circuits per RCD under RGIE). Export the full report as a PDF: row diagram, circuit table, compliance and signature block, standard in the footer, and the panel label strip at the real size of Legrand, Schneider and Hager modules, ready to cut.

NF C 15-100 AND RGIE GUIDE, ROOM BY ROOM
Kitchen, bathroom with zone diagram (0, 1, 2), living room, bedrooms, outdoors, garage with EV charger: mandatory or dedicated circuits, sockets per circuit, required protections, according to the chosen standard. Browsable and filterable cross-sections and protections table. Also ideal for apprentice electricians and home renovation.

SITE MODE (PRO)
Save your electrical panels per worksite, with the standard they were built under, and find them again offline, on any site.

WHY VOLTPRO
— 100% offline: works in the basement, on every site
— No account, no data collection, no ads
— PRO key as a one-time, lifetime purchase: no subscription
— Interface in French, English, Dutch, Portuguese and Romanian, for every crew
— Two standards to choose from: NF C 15-100 (France) and RGIE (Belgium), each worksite keeps its own
— Every result cites its reference in the active standard

Professional electrician, apprentice or renovating homeowner: VoltPro replaces the calculator, paper tables and back-and-forth with the design office for everyday sizing.

VoltPro is a sizing aid: it does not replace the study of a qualified professional, nor the checks of Consuel in France or of the accredited inspection body in Belgium.