ICC G18 Residential Electrician Exam (2017 NEC)

Key Concepts

• Purpose of the Code. "The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or an instruction manual for untrained persons" (90.1(A)).
• Scope — covered. The Code covers "the installation and removal of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables and raceways" for public/private premises, yards and lots, connections to the supply of electricity, and utility office buildings, warehouses, garages, machine shops, and recreational buildings not integral to a generating plant, substation, or control center (90.2(A)).
• Scope — not covered. Installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles; underground mine installations; railway power/signaling installations; communications utility installations; and installations under exclusive control of an electric utility (90.2(B); the verified question on this point is cited as Article 90.2(D)).
• Code arrangement. Nine chapters. Chapters 1–4 apply generally; Chapters 5, 6, and 7 "may supplement or modify the requirements in Chapters 1 through 7"; Chapter 8 is not subject to Chapters 1–7…

Key Concepts

Service placement and clearances - Service conductors supplying a building or other structure shall not pass through the interior of another building or other structure (230.3). - Conductors are considered outside a building when installed under not less than 2 in. of concrete beneath the building or structure (230.6). - Open conductors or multiconductor cable without an overall outer jacket need 3 ft (900 mm) clearance from openable windows, doors, porches, balconies, ladders, stairs, and fire escapes; conductors run above the top level of a window may be less than 3 ft (230.9(A) and Exception). - Overhead service conductors need 10 ft (3.0 m) vertical clearance above finished grade, sidewalks, or platforms where limited to pedestrian traffic only (230.24(B)(1)); 8 ft above a roof surface (230.24(A)). - Overhead conductors, minimum size 8 AWG copper or 6 AWG aluminum/copper-clad aluminum (230.23(B)). Vegetation shall not support service conductors or equipment (230.10). - Service-entrance cable support: within 12 in. (300 mm) of every service head, gooseneck, or connection to a raceway/enclosure and at intervals not exceeding 30 in. (750 mm) (230.51(A)). Where locating the service head above the point of attachment is impracticable, it may be **not farther than 24…

Key Concepts

Feeder minimum size and ampacity (Article 215) - Feeder conductors must have ampacity not less than required to supply the load calculated in Parts III, IV, and V of Article 220, sized to the larger of 215.2(A)(1)(a) or (b) [215.2(A)(1)]. - 215.2(A)(1)(a): with continuous loads, or any combination of continuous and noncontinuous loads, minimum conductor ampacity = noncontinuous load + 125 percent of the continuous load. Exception No. 1 allows 100 percent sizing where the assembly, including the overcurrent devices, is listed for operation at 100 percent of its rating. Exception No. 3 permits grounded conductors not connected to an overcurrent device to be sized at 100 percent. - 215.2(A)(1)(b): not less than the maximum load after applying adjustment or correction factors. - 215.2(A)(2): feeder grounded conductor not smaller than required by 250.122, except 250.122(F) does not apply where grounded conductors run in parallel. - 215.2(A)(3): feeder conductor ampacity shall not be less than that of the service conductors where the feeder conductors carry the total load supplied by service conductors with an ampacity of 55 amperes or less. Commentary: 310.15(B)(7) permits 83 percent of service rating for a 3-wire single-phase dwelling — 2/0 AWG THW copper…

Key Concepts

Overcurrent protection of conductors - Conductors other than flexible cords, flexible cables, and fixture wires must be protected against overcurrent in accordance with their ampacities specified in 310.15, unless otherwise permitted in 240.4(A) through (G) (240.4). - 240.4(B) — The next higher standard overcurrent device rating above conductor ampacity is permitted only if all three conditions are met: (1) the conductors are not part of a branch circuit supplying more than one receptacle for cord-and-plug-connected portable loads; (2) the conductor ampacity does not correspond with a standard fuse/breaker rating; (3) the next higher standard rating selected does not exceed 800 amperes (Handbook Pages 149–150). - 240.4(C) — Where the overcurrent device is rated over 800 amperes, conductor ampacity must be equal to or greater than the device rating. - 240.4(D) Small Conductors — Limits apply after correction factors for ambient temperature and number of conductors: 18 AWG Cu = 7 A (continuous loads ≤ 5.6 A, with breakers/fuses listed and marked for 18 AWG Cu, or Class CC, J, or T fuses) per 240.4(D)(1); 16 AWG Cu = 10 A (continuous ≤ 8 A) per 240.4(D)(2); 14 AWG Cu = 15 A per 240.4(D)(3) (Page 150). -…

Key Concepts

General limitations - Wiring methods in Chapter 3 shall be used for 1000 volts, nominal, or less where not specifically limited; permitted over 1000 volts where specifically permitted elsewhere in the Code — 300.2(A).

Conductor protection against physical damage (300.4) - Cables/raceways laid in notches in wood studs, joists, or rafters shall be protected against nails or screws by a steel plate at least 1.6 mm (1/16 in.) thick, installed before the building finish is applied — 300.4(A)(2). - Installed parallel to framing members or furring strips, the nearest outside surface must be not less than 32 mm (1-1/4 in.) from the nearest edge of the framing member where nails or screws are likely to penetrate — 300.4(D). Where that distance cannot be maintained, use a steel plate/sleeve at least 1/16 in. thick. Steel plates are not required for RMC, IMC, rigid nonmetallic conduit, or EMT (Exception No. 1). - Under metal-corrugated sheet roof decking, not less than 38 mm (1-1/2 in.) from the lowest surface of the decking to the top of the cable, raceway, or box — 300.4(E) (RMC and IMC excepted).

Key Concepts

Luminaire location — bathtub/shower zone. No parts of cord-connected luminaires, chain-, cable-, or cord-suspended luminaires, lighting track, pendants, or ceiling-suspended (paddle) fans may be located within a zone measured 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the top of the bathtub rim or shower stall threshold; the zone includes the space directly over the tub or stall. Luminaires inside the actual outside dimension of the tub/shower up to 8 ft must be marked for damp locations, or wet locations where subject to shower spray — 410.10(D) (Handbook pp. 449–450). Lighting track is also prohibited "where prohibited by 410.10(D)" — 410.151(C)(9).

Luminaires near/over combustible material. Luminaires must be constructed, installed, or equipped with shades or guards so combustible material is not subjected to temperatures above 90°C (194°F) — 410.11 (p. 449); same limit for flush/recessed construction, 410.118. Lampholders over highly combustible material must be unswitched and, unless an individual switch is provided per luminaire, located at least 2.5 m (8 ft) above the floor or guarded — 410.12.

Key Concepts

Swimming pools (Article 680) - At a permanently installed pool, at least one 125-volt, 15- or 20-ampere receptacle on a general-purpose branch circuit must be not less than 6 ft and not more than 20 ft from the inside wall, and not more than 6 ft 6 in. above the floor, platform, or grade [680.22(A)(1)]. Other receptacles: not less than 6 ft [680.22(A)(3)]; circulation/sanitation receptacles at least 6 ft, GFCI-protected, grounding type [680.22(A)(2)]. All 15- and 20-ampere, single-phase, 125-volt receptacles within 20 ft require GFCI [680.22(A)(4)]. - Outdoor luminaires, lighting outlets, and paddle fans above the pool or within 5 ft horizontally: not less than 12 ft above maximum water level [680.22(B)(1)]. Indoors with GFCI protection, totally enclosed luminaires and identified paddle fans may be at 7 ft 6 in. [680.22(B)(2)]. Switching devices: at least 5 ft horizontally unless separated by a solid barrier or listed for closer use [680.22(C)]. Other outlets: not less than 10 ft [680.22(D)]. - Communications, radio, and television coaxial cables within Articles 800–820 are permitted not less than 10 ft above pools, diving structures, and observation stands [680.9(B)]. - Electric pool water heaters: elements subdivided into loads **not exceeding 48 amperes, protected…