Lesson 1NEC 2020+ requirements for services and service disconnects (Articles 230, 230.70)This section covers NEC service requirements, including service entrance conductors, service disconnect locations, grouping, labeling, and emergency access. It emphasizes 230.70 rules and common field violations in commercial buildings.
Service entrance conductors and routingService disconnect location and accessibilityNumber, grouping, and identification of disconnectsService equipment working space and clearancesLabeling, signage, and utility coordinationLesson 2Wiring methods and installation requirements for conduit, cable, flexible cords (Articles 330, 340, 348, 400)This section reviews NEC rules for MC, UF, flexible metal conduit, and flexible cords in commercial work. It covers permitted uses, securing and supporting, fittings, terminations, and common inspection issues for these wiring methods.
Uses and limits of MC and UF cablesFlexible metal conduit routing and supportProtection at terminations and fittingsFlexible cord types and permitted usesBox fill, derating, and cable assembliesLesson 3Grounding and bonding fundamentals and NEC requirements (Articles 250)This section presents grounding and bonding fundamentals under NEC 250, including objectives, permitted methods, and key rules for commercial services, feeders, and separately derived systems, with emphasis on safe fault clearing and touch voltage control.
Objectives of grounding and bonding systemsGrounding of services and main disconnectsGrounding separately derived systemsBonding of metal piping and structural steelGrounding and bonding documentation reviewLesson 4Key definitions and scope: premises wiring, services, feeders, branch circuits, equipmentThis section clarifies NEC definitions for premises wiring, services, feeders, branch circuits, and equipment. It helps inspectors correctly identify system parts, apply scope limits, and distinguish utility equipment from customer-owned wiring.
Premises wiring versus utility supplyService conductors and service equipmentFeeders and feeder tap conductorsBranch circuits and utilization equipmentSeparately derived systems and transformersLesson 5Equipment grounding conductors, electrode systems, and bonding jumpers — details and sizingThis section focuses on equipment grounding conductors, grounding electrode systems, and bonding jumpers. It explains sizing from NEC tables, material choices, terminations, and inspection checks for continuity and fault current paths.
Grounding electrode conductors and electrodesEquipment grounding conductor types and sizingMain and system bonding jumper functionsBonding of raceways, enclosures, and fittingsTesting continuity of grounding pathsLesson 6Branch circuits and receptacles: ratings, allowed loads, multiwire branch circuits (Article 210)This section explains NEC branch circuit rules for receptacles in commercial spaces, including ratings, load calculations, multiwire branch circuits, required receptacle locations, and inspection checks for overloading and improper sharing of neutrals.
General branch circuit ratings and typesReceptacle placement in commercial areasContinuous and noncontinuous load sizingMultiwire branch circuits and handle tiesGFCI and AFCI protection for receptaclesLesson 7Special location rules: damp, wet, and dry locations; outdoor equipment; corrosion and mechanical protection (Articles 110, 300, 314)This section addresses NEC rules for damp, wet, and dry locations, outdoor equipment, and corrosion and mechanical protection. It guides inspectors on enclosure ratings, fittings, sealing, and physical protection for raceways and cables.
Classifying damp, wet, and dry locationsEnclosure and raceway ratings for outdoorsCorrosion protection for metallic systemsMechanical protection for cables and conduitsSealing fittings and condensation controlLesson 8NEC requirements for emergency systems, signage, and disconnecting means for equipment (Articles 700–705, 750)This section explains NEC rules for emergency systems, legally required standby, optional standby, and interconnected power sources. It covers transfer equipment, signage, disconnecting means, and inspection focus for Articles 700 through 705 and 750.
Emergency versus standby system categoriesTransfer switches and source interconnectionsRequired signage and identification markingsDisconnecting means for generators and invertersEmergency circuit wiring and separation rulesLesson 9Structure and organization of the National Electrical Code (NEC) — how to find applicable articles and tablesThis section shows how the NEC is structured, from chapters and articles to parts, sections, and tables. It trains inspectors to quickly locate applicable rules, exceptions, and annexes for commercial and light industrial installations.
NEC chapters, articles, and parts layoutMandatory rules, permissive rules, and notesFinding applicable tables and calculation rulesUsing annexes, fine print notes, and indexesCross-referencing articles for complex systemsLesson 10Overcurrent protection and conductor ampacity: NEC tables, adjustment and correction factors (Articles 240, 310)This section details NEC overcurrent protection and conductor ampacity rules, including use of Tables 240.6 and 310.16, adjustment and correction factors, tap rules, and coordination concerns for commercial and light industrial feeders and branch circuits.
Standard overcurrent device ratings and typesSelecting OCPD for feeders and branch circuitsUsing ampacity tables and temperature ratingsAdjustment and correction factor applicationTap conductors and transformer secondary rules
