Electrical Guides & Tutorials

Practical guides for electrical work, written for electricians and engineers.

How to Calculate Voltage Drop

The voltage drop formula, the NEC 3% rule and worked examples

Choosing conductor size from ampacity, voltage drop and conduit fill

How power, current and voltage relate, with conversions

kW, kVA, kVAR and the root-3 factor explained

Voltage, current, resistance and power relationships with examples

Sizing the circuit, wire and breaker for a Level 2 EV charger

Fast, free calculators for electricians and engineers