THHN / THWN-2 Wire Explained: Ratings, Uses & Where It’s Allowed
THHN wire meaning, THHN vs THWN vs THWN-2 ratings, ampacity from NEC Table 310.16, and exactly where the Code allows it. A field guide for electricians.
Type W Cable Explained: Portable Power Cable Ratings, Uses & NEC 400 Rules
Type W is a 2000 V portable power cable under NEC Article 400 — not a wet-location suffix. Ratings, construction, ampacity from Table 400.5(B), and where the Code permits and prohibits it.
NFPA 70E 2026 Updates: Arc Flash Code Changes & What’s New
What's changed in arc flash safety in 2026 - the 2024 NFPA 70E current edition, the 2026 NEC arc flash labeling mandate, November 2024 OSHA guidance, NFPA 70B updates, and what to audit now.
Bare Copper Ground Wire: NEC Sizing & Code Rules Explained
Complete NEC guide to bare copper ground wire: EGC sizing from Table 250.122, the 250.122(B) upsizing rule, GEC rules under 250.64, and where bare copper is required.
NEC 2026 Code Book: Key Changes, New Rules & What Electricians Need to Know
NEC 2026 changes explained for electricians: arc flash labels, AFCI in bathrooms & garages, EV charging rules, 2 VA/ft2 load calc, and the structural reorganization.
Electrical Gutters (Auxiliary Gutters): NEC Article 366 Rules & Sizing Guide
Complete guide to electrical gutters (auxiliary gutters) under NEC Article 366 — permitted uses, the 20% fill rule, conductor sizing, ampacity adjustment, vs wireways, and a worked sizing example.
Branch Circuit Types Explained: General Purpose, Appliance & Individual
Complete guide to branch circuit types — general purpose, appliance, individual, and multiwire. NEC 210.23 permissible loads, the 80% and 50% rules, ratings, and worked examples.
Transformer Sizing Chart: How to Size a Transformer by kVA
Complete transformer sizing guide — kVA formulas for single-phase and three-phase, standard kVA sizes chart, NEC 450.3 OCPD sizing, power factor, K-factor, and 6 worked examples.
NEC Code Book Editions: 2017 vs 2020 vs 2023 vs 2026 Differences
Complete comparison of NEC 2017, 2020, 2023, and 2026 editions. Key changes between editions, state adoption map, which edition to use for your exam, and what changed when.
Electrical Room Signage: NEC & NFPA Requirements for Panels & Equipment
Complete guide to required electrical room signage — NEC 110.21, arc flash labels (110.16), fault current marking, available fault current, working clearance signs, and OSHA requirements.
GFCI vs Arc Fault (AFCI): Differences, Requirements & Where Each Is Required
Complete guide to GFCI vs AFCI — how each works, the hazard each prevents, every NEC 2023 required location, dual-function devices, and how they differ from regular breakers.
Intersystem Bonding Termination: What It Is & NEC Requirements
Complete guide to intersystem bonding terminations (IBT) under NEC 250.94 — the six IBT conditions, other means option, where to install, which systems require bonding, and 2023 changes.
