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HI Electrician: National Electrical Code (NEC) Requirements

HI Electrician · Work through your exam, one topic at a time.

All guide sections

National Electrical Code (NEC) Requirements

This domain tests how well you can find and apply Code rules, not just recall isolated numbers. The exam draws heavily from Articles 210, 220, 230, 240, 250, 300, 310, 314, 334, 404, 406, and 430, and it expects you to know which article governs a given installation.

How the Code is organized

Chapters 1 through 4 are general rules; Chapter 5 covers special occupancies; Chapter 6 special equipment; Chapter 7 special conditions; Chapter 8 communications; Chapter 9 tables. Article 90 gives scope, Article 100 definitions, and Article 110 general installation requirements. When two rules conflict, the more specific article usually controls.

High-yield rules

  • 210.8 GFCI protection: dwelling bathrooms, garages, outdoors, kitchens, laundry areas, and receptacles near sinks, with expansions in recent editions.
  • 210.12 AFCI protection for dwelling branch circuits in bedrooms, kitchens, laundry, and similar areas.
  • 210.52 receptacle spacing: no point along the floor line more than 6 ft from a receptacle; wall spaces 2 ft or wider need coverage.
  • 210.70 lighting outlets for dwelling rooms, stairs, and equipment spaces.
  • 220.42 demand factors; 240.4 protection; 240.6 standard ratings; 250 grounding; 300.4 physical protection; 314.16 box fill.

Worked example

A 2,000 ft² dwelling: general lighting at 3 VA/ft² = 6,000 VA; two small-appliance circuits at 1,500 VA = 3,000 VA; laundry = 1,500 VA; total = 10,500 VA. Table 220.42 applies 100% to the first 3,000 VA and 35% to the remaining 7,500 VA = 2,625 VA, giving 5,625 VA. At 240 V that is 23.4 A. A one-family dwelling service is not permitted below 100 A under 230.79(C). The reasoning: demand factors apply after the general lighting, small-appliance, and laundry loads are summed.

Traps that cost marks

  • Applying the 35% demand factor to the entire load instead of only the portion above 3,000 VA.
  • Confusing GFCI and AFCI locations.
  • Measuring the 6 ft receptacle rule from the receptacle instead of along the wall line.
  • Forgetting the 125% continuous-load factor.
  • Applying Table 310.16 ampacity without checking termination temperature and 240.4(D).
  • Ignoring wall space interrupted by doorways and similar openings.