NEC Quick Reference

Essential electrical formulas, NEC tables, and reference charts at your fingertips. 13 categories with 84+ reference items.

Electrical Formulas

Essential DC, AC single-phase, three-phase, power factor, and impedance formulas.

Copper and aluminum conductor ampacity tables with derating and correction factors.

AWG conductor physical properties, resistance values, and insulation type ratings.

Maximum conductor counts for EMT, RMC, and PVC conduit with fill percentage rules.

Offset multipliers, shrinkage values, stub-up deducts, and common bend types.

Conductor volume allowances, standard box sizes, and box fill calculation examples.

Single-phase and three-phase voltage drop formulas, lookup tables, and max distance charts.

Straight blade and locking (twist-lock) receptacle configurations with specs and wiring.

Full-load current tables, branch circuit sizing, OCPD sizing, and NEMA starter sizes.

EGC and GEC sizing tables, grounding electrode types, and requirements.

Transformer formulas, delta-wye connections, full-load currents, and OCPD sizing.

Blueprint symbols for receptacles, switches, lighting, panels, wiring, and motor controls.

AWG to metric, temperature, length, electrical unit, and fraction-to-decimal conversions.

Use our NEC calculators to run the numbers based on these reference tables.

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