Lesson 1NEC 2020+ requirements for services and service disconnects (Articles 230, 230.70)This lesson covers NEC service rules, including service entrance conductors, disconnect positions, grouping, labelling, and emergency access. It highlights 230.70 guidelines and frequent violations observed in commercial buildings in Namibia.
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 lesson examines NEC provisions for MC, UF, flexible metal conduit, and flexible cords in commercial projects. It addresses allowed applications, securing and supporting, fittings, terminations, and typical inspection problems for these wiring methods in Namibian contexts.
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 lesson introduces grounding and bonding basics under NEC 250, covering goals, approved methods, and crucial rules for commercial services, feeders, and separately derived systems, with focus on safe fault clearing and touch voltage management in Namibia.
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 lesson clarifies NEC definitions for premises wiring, services, feeders, branch circuits, and equipment. It assists inspectors in accurately identifying system components, applying scope boundaries, and differentiating utility equipment from customer-owned wiring in Namibian installations.
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 lesson concentrates on equipment grounding conductors, grounding electrode systems, and bonding jumpers. It describes sizing using NEC tables, material options, terminations, and inspection verifications for continuity and fault current paths in Namibian environments.
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 lesson outlines NEC branch circuit rules for receptacles in commercial areas, covering ratings, load computations, multiwire branch circuits, required receptacle positions, and checks for overloading and improper neutral sharing in Namibian commercial spaces.
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 lesson tackles NEC rules for damp, wet, and dry locations, outdoor equipment, and corrosion and mechanical safeguards. It directs inspectors on enclosure ratings, fittings, sealing, and physical protection for raceways and cables in Namibian conditions.
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 lesson describes NEC rules for emergency systems, legally required standby, optional standby, and interconnected power sources. It includes transfer equipment, signage, disconnecting means, and inspection priorities for Articles 700 through 705 and 750 in Namibia.
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 lesson demonstrates the NEC structure, from chapters and articles to parts, sections, and tables. It equips inspectors to swiftly find relevant rules, exceptions, and annexes for commercial and light industrial setups in Namibian facilities.
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 lesson elaborates on NEC overcurrent protection and conductor ampacity rules, including Tables 240.6 and 310.16, adjustment and correction factors, tap rules, and coordination issues for commercial and light industrial feeders and branch circuits in Namibia.
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
