Electrical Engineering Reference & Sizing Articles
In-depth technical guides, formula derivations, code compliance explanations (NEC 2023 / IEC 60364 / IEEE), and step-by-step practical worked examples.
Hot Tub Wiring: 50 Amp GFCI Circuit, Wire Size and NEC 680 Rules
Wire a 240V hot tub safely: 50A GFCI protection per NEC 680.44, 6 AWG copper conductors, an insulated equipment ground, and a disconnect within sight of the tub.
EV Charger Circuit Sizing: Breaker, Wire and Outlet Guide
How to size a home EV charging circuit the NEC way: charging is a continuous load at 125%, so a 48A charger needs a 60A circuit. Includes the NM-B trap that fails inspections.
Wire Size for a 100 Amp Service: Copper, Aluminum and Distance
The exact conductors for a 100A residential service: 4 AWG copper or 2 AWG aluminum under NEC 310.12, plus grounding sizes and voltage-drop checks for long runs.
Grounding vs. Bonding: NEC Article 250 Principles & Conductor Sizing
Comprehensive engineering reference on the vital distinctions between grounding (connecting to earth) and bonding (joining metallic parts to create a low-impedance fault clearing path) under NEC Article 250.
Conduit Fill Percentage and Jam Ratio Calculation Guide
Learn how to calculate conduit fill capacity per NEC Chapter 9 (Tables 1, 4, and 5), avoid cable jamming on multi-conductor pulls, and size pull boxes.
Solar Battery Bank Sizing Guide: Depth of Discharge & Peukert Derating
Comprehensive engineering sizing guide for off-grid and backup solar battery banks, incorporating daily Watt-hour audits, Depth of Discharge limits, temperature derating, and Peukert factor effects.
Transformer Sizing and Full-Load Current Calculation Guide
Learn how to calculate primary and secondary full-load amps for single-phase and three-phase transformers, determine required kVA capacity, and size overcurrent protection per NEC Article 450.
How to Calculate Three-Phase Motor Full-Load Amps (FLA) & Sizing
Step-by-step engineering guide to calculating three-phase induction motor full-load current, starting inrush, branch conductor sizing (125%), and overcurrent protection per NEC Article 430.
Battery Engineering Fundamentals: Ah, Wh, C-Rate & Chemistry
Essential technical reference covering battery capacity metrics (Ah vs. Wh), Depth of Discharge (DoD), State of Charge (SoC), C-rates, cycle life, and Lead-Acid vs. Lithium comparison.
Power Factor in AC Circuits: Theory, Triangle & Correction
Complete guide to AC power factor, the power triangle (kW, kVA, kVAR), leading vs. lagging power factor, utility penalties, and power factor correction capacitors.
Understanding Voltage Drop: Formulas, Consequences & Mitigation
Learn what causes voltage drop in electrical wiring, how to calculate resistance losses over long distances, code recommendations, and how to prevent brownouts.
Electrical Wire Sizing: Engineering Principles & Code Considerations
In-depth guide to properly sizing electrical conductors based on thermal ampacity, voltage drop limits, ambient temperature correction, and conduit bundling factors.
Ohm's Law: Theory, Formula Wheel, and Practical Engineering
A comprehensive guide to understanding Georg Ohm's fundamental electrical law, the Ohm's law circle formula wheel, limitations, and practical circuit examples.
Master Electrical Formulas & Equations Cheat Sheet
Complete engineering reference cheat sheet covering DC circuits, AC single-phase & three-phase formulas, Ohm's law, power, impedance, reactance, and transformer ratios.
How to Size Electrical Wire Properly: NEC Ampacity & Voltage Drop
Complete practical guide to sizing copper and aluminum electrical wire using ampacity tables, temperature correction, conduit fill derating, and voltage drop formulas.
How to Size a Power Inverter for Off-Grid, RV & Backup Systems
Learn how to calculate continuous wattage, surge startup wattage, waveform selection (Pure Sine Wave vs. Modified), and DC cable sizing.
How to Size a Battery Bank for Solar, RV & Backup Power
Complete step-by-step sizing guide for calculating required battery capacity (Ah and Wh), Depth of Discharge, and temperature derating.
How to Calculate Voltage Drop: Step-by-Step Engineering Guide
Learn how to calculate cable voltage drop for long wire runs, apply NEC 3% and 5% rules, and select correct conductor sizes.
How to Calculate Electrical Power: Step-by-Step Guide
Master calculating Watts, Kilowatts, VA, and Horsepower for DC and AC circuits with clear worked formulas and practical examples.