Electrician's Handbook — electrical wiring diagrams, theory and calculators for electricians, students and installers. Theory, diagrams and calculators work offline. No ads. No subscriptions. — Theory A variety of topics in electrical engineering: from basic concepts to grounding and lighting diagrams. Some topics include exercises with answers for self-check. — Diagrams Interactive electrical diagrams. You can interact with elements to better understand how they work. — Calculators A section with calculators, formulas, and useful reference tables. — Tests Built-in tests to check your knowledge. — Contents of the "Theory" section: Basic concepts • Voltage, current, resistance, power • Ohm’s Law, Kirchhoff’s rules • Parallel and series connections • Short circuits, safety precautions • Electrical engineering terms Electromechanical converters • Transformer, generator, electric motor • Connecting a three-phase motor using a capacitor Protection and automation devices • Circuit breaker, RCD, RCBO • Voltage monitoring relay, contactor, fuses • Surge protection devices Cables and wires • Wire connection methods • Selecting cross-section by current and power • Color coding • Electrical panel Power stations and substations • Nuclear, thermal, solar, hydro, wind, and geothermal power stations Measuring instruments • Voltmeter, ammeter, ohmmeter, multimeter • Clamp meter • Electricity meter Grounding • Types of grounding systems • Equipotential bonding system Lighting • Incandescent, LED, and other types of lamps • Lamp holders, bases, lumens, lux • Color temperature • LED strip Work execution • Socket repair • Installation of flush-mounted and surface-mounted sockets • Switch installation Additional information • Power supply categories • Surge overvoltages • IP protection rating • Electrician’s tools • Types of outlets and plugs, voltages in different countries • Joule’s Law, Coulomb’s Law • Right-hand and left-hand rules — Contents of the "Diagrams" section: • Switch (1 and 2 gang) • Three-gang switch • Two-way switch • Two-way switch with intermediate switch • Outlets and switch in one block • Lighting with dimmer • Motion sensor lighting • Relay with light sensor • Lighting with impulse relay • Fluorescent lamp wiring • Socket wiring diagrams • Magnetic starter for motor • Star and delta motor connection — Contents of the "Calculators" section: • Basic formula calculator • Electricity cost calculator • SI unit system and metric prefixes • Diameter ↔ cross-section table • AWG to mm and mm to AWG conversion • Electronic component symbols