NEC / NFPA 70 (National Electrical Code)
US national standard for electrical installations. Covers conductor sizing per Article 310, ampacity tables, conduit fill, and the terminal temperature rating rule.
NEC 2026 Conductor Sizing — Article 310 Changes & Key Requirements
NEC 2026 conductor sizing changes explained. Article 310 ampacity tables, terminal temperature rules & installation methods. Free reference guide.
NEC Table 310.16 Ampacity Chart Explained [2026]
NEC Table 310.16 ampacity chart for conductors in raceways and cables. Copper and aluminium, 60/75/90°C columns. Free calculator included.
NEC Voltage Drop Calculator & Guide — Free [2026]
NEC voltage drop calculation guide. 3% branch circuit, 5% total recommendation. Chapter 9 Table 9. Free calculator included — no signup.
NEC Conduit Fill Calculator & Guide — Chapter 9 [2026]
NEC conduit fill rules explained. Chapter 9 Tables 1, 4, 5. Maximum conductors per conduit for EMT, PVC, rigid. Free calculator — no signup.
NEC Table 310.15(B)(1): Temperature Correction Factors
NEC Table 310.15(B)(1) explained — ambient temperature correction factors for 60°C, 75°C, and 90°C conductor columns. How to apply temperature derating per NFPA 70.
NEC Table 310.15(C)(1): Conduit Fill Adjustment Factors
NEC Table 310.15(C)(1) explained — conduit fill adjustment factors for 4-6, 7-9, 10-20, 21-30, and 41+ conductors. How to count current-carrying conductors.
NEC Article 220: Branch Circuit & Feeder Load Calculations
NEC Article 220 explained — general lighting loads, demand factors, dwelling unit calculations, commercial load calculations. Table 220.12 and Table 220.42 reference.