Electrician Math: Ohm's Law, Load Calculations, Voltage Drop & Conduit Fill
Ohm's law and the power wheel, series and parallel circuits, single- and three-phase power with √3 and power factor, a dwelling load calculation with demand factors, conductor sizing with temperature and bundling factors, voltage drop with a 3 % size pick, conduit and box fill, and motor overload and breaker sizing with a chart: 8 graded labs for apprentices and license-exam practice. Illustrative tables, not affiliated with NFPA or any code body; your local code applies.
The first lesson is free — no account needed.
About this course
An electrician math course that works through the jobs of one fictional contractor, Copperline Electric, in a spreadsheet, for electrical apprentices, students preparing for a license exam and working electricians. You turn nameplate watts into amps and ohms with Ohm's law and the power wheel, solve series and parallel circuits, calculate kVA, kW and line current for single- and three-phase loads with √3 and the power factor, build a dwelling load calculation with demand factors and a service size, size conductors with temperature and bundling factors, calculate voltage drop with VD = 2·K·I·L ÷ CM and pick a size for 3%, check conduit and box fill, and size motor overloads and breakers with a chart. Illustrative tables, with no affiliation with the NFPA or any code body. Your local code (NEC, IEC-based or other) applies, and the course is no substitute for a licensed electrician. The first lab is free.
Lessons
- Ohm's Law & the Power Wheel: Volts, Amps, Ohms & WattsFree
- Series & Parallel Circuits: Total Resistance, Current & Voltage Drops Pro
- Single- vs Three-Phase Power: √3, Power Factor, kVA & kW Pro
- Dwelling Load Calculation: VA per ft², Demand Factors & Service Size Pro
- Conductor Sizing: Ampacity, Temperature Correction & Bundling Factors Pro
- Voltage Drop: VD = 2·K·I·L ÷ CM and Choosing a Size for 3 % Pro
- Conduit & Box Fill: Percent of Area and Conductor Counts Pro
- Motor Circuits: Full-Load Current, Overloads & Breaker Sizing (Chart) Pro