ICC R17 Journeyman Electrician Exam (2023 NEC)
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Every practice exam shows your time per question against the real exam's clock (3:00 here), and each topic lands in one of these:
What's on the exam
Questions per topic, out of 80Topics
General Knowledge
2023 NEC · Ugly's Electrical References
Key Concepts
NEC Purpose, Scope, and Arrangement (Article 90) - 90.1 Scope: Article 90 covers use and application, arrangement, and enforcement of the Code; the expression of mandatory, permissive, and nonmandatory text; examination of equipment; wiring planning; and use and expression of measurements. - 90.2(A): The purpose of the Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. It is not a design specification or instruction manual for untrained persons. - 90.2(C) Installations Covered: public and private premises including buildings, structures, mobile homes, recreational vehicles, and floating buildings; yards, lots, parking lots, carnivals, industrial substations; shore power to ships and watercraft in marinas and boatyards. - 90.2(D) Installations 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 and self-propelled mobile surface mining…
Services and Service Equipment
Based on the 2023 NEC
Key Concepts
Service disconnecting means rating. For a one-family dwelling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-wire (230.79(C)). The minimum ampacity for ungrounded service conductors shall not be less than the rating of the service disconnecting means specified in 230.79(A) through (D) (230.42(B)).
Overhead service conductor clearances (not over 1000 volts, nominal) — 230.24: - Above roofs: not less than 2.6 m (8 ft 6 in.), maintained not less than 900 mm (3 ft) in all directions from the roof edge (230.24(A)). - Vertical clearance from final grade (230.24(B)): 3.0 m (10 ft) at the service entrance / drip loop and above areas or sidewalks accessible only to pedestrians (conditions apply); 3.7 m (12 ft) over residential property and driveways and commercial areas not subject to truck traffic ≤300 V to ground; 4.5 m (15 ft) for those areas where voltage…
Feeders
2023 NEC — Article 215 (Feeders), Article 220 (load calculations), Article 225 (outside branch circuits and feeders)
Key Concepts
Feeder conductor sizing (215.2(A)(1)). Where a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum feeder conductor size shall have an ampacity not less than the noncontinuous load plus 125 percent of the continuous load. Exception No. 1: if the assembly, including the overcurrent devices protecting the feeder(s), is listed for operation at 100 percent of its rating, the ampacity may be not less than the sum of the continuous plus noncontinuous load. Exception No. 3: grounded conductors not connected to an overcurrent device may be sized at 100 percent of the continuous and noncontinuous load. Feeder conductors must have an ampacity not less than the larger of 215.2(A)(1) or (A)(2) and comply with 110.14(C).
Branch Circuits and Conductors
Key Concepts
Conductor basics (Article 310) - Minimum conductor size for voltage ratings up to and including 2000 volts: 14 AWG copper or 12 AWG aluminum/copper-clad aluminum, except as permitted elsewhere — 310.3(A). - Conductors 8 AWG and larger installed in raceways shall be stranded, unless permitted or required elsewhere to be solid — 310.3(C). - Conductors may be paralleled only in sizes 1/0 AWG and larger — 310.10(G)(1). Paralleled conductors must be the same length, same material, same circular mil size, same insulation type, and terminated in the same manner. - AWG size or circular mil area shall be repeated at intervals not exceeding 610 mm (24 in.) on surface-marked wire and cable; all other markings not exceeding 1.0 m (40 in.) — 310.8(B)(1).
Wiring Methods and Materials
Key Concepts
Protection from physical damage (300.4) - Bored holes in wood members: edge of hole not less than 32 mm (1¼ in.) from the edge of the member; otherwise protect with a steel plate at least 1.6 mm (1/16 in.) thick — NEC 300.4(A)(1). - Notches in wood members: protect with a steel plate at least 1.6 mm (1/16 in.) thick, of appropriate length and width — NEC 300.4(A)(2). - Cables/raceways parallel to framing members or furring strips: nearest outside surface not less than 32 mm (1¼ in.) from the nearest edge where nails or screws are likely to penetrate — NEC 300.4(D). - Under metal-corrugated sheet roof decking: not less than 38 mm (1½ in.) from the lowest surface of the decking to the top of the cable, raceway, or box — NEC 300.4(E).
Equipment and Devices
Key Concepts
Luminaires — clearances and temperature - Luminaires shall be constructed, installed, or equipped with shades or guards so combustible material is not subjected to temperatures above 90°C (194°F) — 410.11 (also 410.115(A), 410.120, 410.97 for lampholders). - Lampholders over highly combustible material: at least 2.5 m (8 ft) above the floor, or located/guarded so lamps cannot be readily removed or damaged, unless an individual switch is provided for each luminaire — 410.12. - Bathtub/shower zone: no cord-connected luminaires, chain-/cable-/cord-suspended luminaires, lighting track, pendants, or paddle fans with light kits within 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically of the bathtub rim or shower threshold — 410.10(D). Air-conditioning and refrigeration equipment is barred from the same zone — 440.8. - Clothes closets: 300 mm (12 in.) clearance for surface-mounted incandescent or LED luminaires with completely enclosed light sources; 150 mm (6 in.) for surface-mounted fluorescent — 410.16(D). Storage space…
Control Devices
2023 NEC — Articles 404, 409, and 430
Key Concepts
Switches (Article 404) - An ac general-use snap switch may control motor loads not exceeding 80 percent of the ampere rating of the switch at its rated voltage [404.14(A)]. It may also control resistive and inductive loads not exceeding the switch's ampere rating at the applied voltage. - An ac–dc general-use snap switch may control inductive loads not exceeding 50 percent of the switch's ampere rating at the applied voltage; switches rated in horsepower are suitable for motor loads within their rating [404.14(B)]. - Switches shall be listed and marked with their ratings [404.14].
Controllers and their ratings/markings - A general-use switch may serve as the controller for stationary motors rated 2 hp or less and 300 volts or less where the switch has an ampere rating not less than twice the motor full-load current [430.83(C)]. - **Combination motor controllers employing adjustable instantaneous trip…
Motors and Generators
Key Concepts
Use table FLC, not nameplate. Per 430.6(A)(1), the values in Table 430.247, 430.248, 430.249 and 430.250 are used instead of nameplate current to determine conductor ampacity, current ratings of switches, and branch-circuit short-circuit and ground-fault (SC/GF) protection ratings. Nameplate current is used for separate motor overload protection and for motors built for low speeds (less than 1200 RPM), high torques, canned pumps, or multispeed motors [430.6(A)(2)]. A verified question confirms it is false that nameplate amperes may be used to size an inverse time breaker (430.52(B)). Ugly's "General Motor Rules" (Page 41) restates: "Use full-load current from tables instead of nameplate."
Branch-circuit conductors — 125%. Conductors supplying a single continuous-duty motor shall have an ampacity not less than 125 percent of the motor full-load current rating as determined by 430.6(A)(1) [430.22, 430.22(A); Ugly's Pages 41–42].
Special Occupancies, Equipment, and Conditions
Key Concepts
Hazardous location classification - Class I, Division 1 = ignitible gas/vapor present under normal conditions — 500.5(B)(1). - Group D covers flammable gas/vapor with MESG greater than 0.75 mm or MIC ratio greater than 0.80; a typical Group D material is propane — 500.6(A)(4). - Zone Group IIIC = combustible metal dust, including combustible metal fibers/flyings (IIIB = non-metal dust; IIIA = fibers/flyings) — 506.6. - Conduit seals in Class I, Division 1 shall be within 450 mm (18 in.) of the enclosure; only threaded couplings or explosionproof fittings between the seal and the enclosure — 501.15(A)(1). - Zone 22: Type MC or Type MI cable with listed termination fittings is a permitted wiring method — 506.15(C). Types NM and UF are never permitted in hazardous (classified) locations.