ICC G17 Journeyman Electrician Exam (2017 NEC)

Key Concepts

NEC Article 90 – Structure, Scope, and Enforcement

• Purpose (90.1): The NEC exists for practical safeguarding of persons and property from electrical hazards. It is not a design spec or instruction manual.
• Scope (90.2): Covers installation/removal of conductors, equipment, raceways, signaling/communications conductors, and optical fiber cables on public/private premises. Does not cover utility generation plants, transmission lines, or utility-owned substations that are integral to generation.
• Code Arrangement (90.3): Chapter 1–4 apply generally; Chapters 5–7 supplement or modify Chapters 1–4; Chapter 8 (communications) is independent.
• Enforcement (90.4): The AHJ (Authority Having Jurisdiction) interprets and enforces the NEC.
• Mandatory vs. Permissive Rules (90.5): "Shall" = mandatory; "Shall not" = prohibition; "Should" = advisory; "May" / "Permitted" = permissive.

Key Concepts

Arc-Flash Hazard Warning (110.16) - All switchboards, switchgear, panelboards, industrial control panels, meter socket enclosures, and motor control centers in other than dwelling units must be field-marked to warn of arc-flash hazards. - 110.16(B) — Service equipment in other than dwelling units must be legibly field-marked with the available fault current AND the date the calculation was performed. This marking must be visible during inspection.

Available Fault Current Marking (110.24) - 110.24(A): Service equipment must be marked with the available fault current. Required in other than dwelling units. - 110.24(B): If modifications are made to the electrical system, the fault current data must be recalculated and the marking updated.

Key Concepts

Scope (215.1): Article 215 covers installation requirements, overcurrent protection, minimum size, and ampacity of feeder conductors. Load calculations are governed by Article 220, Parts III, IV, and V.

Minimum Ampacity (215.2(A)(1)(a)): Feeder conductors must have an allowable ampacity not less than: - 100% of noncontinuous load + 125% of continuous load - Exception: If the assembly (including OCPD) is listed for 100% operation, conductors may be sized at 100% of continuous + noncontinuous load combined. - Grounded (neutral) conductors not connected to an OCPD may be sized at 100% of continuous and noncontinuous load (Exception No. 3).

Overcurrent Protection (215.3): Feeder OCPDs must be sized to protect the feeder conductors per Article 240. The OCPD rating must not exceed the conductor's allowable ampacity unless standard ratings apply.

Key Concepts

Branch Circuit Basics (Article 210) - Branch circuits are rated by the overcurrent protective device: 15A, 20A, 30A, 40A, and 50A are standard ratings. - A 15A receptacle is permitted on a 20A circuit; a 20A receptacle requires a 20A circuit. - Small appliance branch circuits (210.11(C)(1)): minimum two 20A circuits required for kitchen receptacles. - Bathroom circuits: at least one 20A circuit required; may serve multiple bathrooms (210.11(C)(3)).

Grounded Conductor Identification (Article 200) - Sizes 6 AWG or smaller: white or gray insulation, or three continuous white/gray stripes (200.6(A)). - Sizes 4 AWG or larger: white/gray color, white/gray stripe, or other approved marking (200.6(B)). - A white conductor used as an ungrounded conductor must be re-identified with tape, paint, or markings at all visible points (200.7(C)). - Grounded conductor continuity shall NOT depend on connection to a metallic enclosure, raceway, or cable armor (200.2(B)).

(2017 NEC | 21 questions | 26% of exam)

Key Concepts

Article 300 — General Wiring Requirements

• 300.3(B): All conductors of the same circuit must be in the same raceway, cable, or trench — prevents inductive heating in metal raceways.
• 300.4: Physical protection rules are critical:
• Cables/raceways through wood members: drill hole must be ≥1-1/4 in. from edge, or install a 1/16 in. steel plate (nail plate).
• Cables parallel to framing members must be kept ≥1-1/4 in. from the edge of the framing.
• Cables in shallow grooves in masonry or concrete require a 1/16 in. steel plate or sleeve.
• 300.5: Underground cover requirements — memorize Table 300.5. Key depths: direct burial cable (UF/USE) = 24 in. general; 12 in. under a residential driveway; RMC/IMC = 6 in.; GFCI-protected or listed ≤30V = 12 in.
• 300.7(A): Raceways running between areas of different temperatures must be sealed…

(2017 NEC | 10 questions, 12% of exam)

Key Concepts

Fixture Wires (Article 402) - Minimum size: 18 AWG (402.6). No smaller, period. - All fixture wire types are rated for 600V unless otherwise noted — KF-1, KFF-1, SF-1, SFF-1, and RFH-1 are limited to 300V (Table 402.3). - Conduit fill follows Chapter 9, Table 1 percentages; use Tables 4 and 5 for area calculations (402.7). - Temperature ratings vary widely: TF = 60°C, FFH-2/RFH = 75°C, RFHH-2 = 90°C, SF-2/KF-2/PF = 200°C, PAF/PTF = 250°C.

Luminaires & Recessed Lighting (Article 410) - Recessed luminaires must maintain clearance from thermal insulation unless IC-rated (insulation-contact rated). - Non-IC-rated fixtures require 3 inches minimum clearance from insulation and ½ inch from combustible materials. - Conductors in luminaire raceways must be rated for the operating temperature at that location (often 90°C minimum near lamp). - Luminaires in clothes closets: surface-mounted fluorescent or LED luminaires are permitted;…

(3 questions, 4% of exam | NEC 2017)

Key Concepts

Motor Controller Ratings & Marking (Article 430, Part VII)

• Every motor controller must be marked with horsepower (HP) rating, voltage, current rating, and short-circuit current rating (SCCR).
• Controllers must be rated for the motor they control — not necessarily the same ampacity as the branch-circuit conductors.
• A branch-circuit protective device (OCPD) may serve as the controller for motors 1/8 HP and under (430.81).

Motor Control Circuit Overcurrent Protection (Article 430, Part VI)

• Control circuits tapped from the load side of the motor branch-circuit OCPD must have their own overcurrent protection unless the conductors are protected by the motor branch-circuit OCPD (430.72).
• Class 1 control circuit conductors (14 AWG and larger) are protected per Table 310.15(B)(16); 18 AWG and 16 AWG fixture wire types are permitted (430.72(B)).
• If control circuit conductors leave the controller enclosure, they…

2017 NEC | Article 430 | ~5 questions, 6% of exam

Key Concepts

Branch-Circuit Conductor Sizing (430.22) Single motor conductors must be sized at 125% of the motor's full-load current (FLC) from NEC Table 430.247–430.250 — not the nameplate current. Always use the table values unless specifically directed otherwise.

Branch-Circuit Short-Circuit and Ground-Fault Protection (430.52) Protection devices are selected using Table 430.52, which gives maximum ratings as a percentage of FLC for each device type and motor type. If the calculated value doesn't match a standard rating, you may round up to the next standard size — with caps: - Non-time-delay fuse: 300% max - Dual-element (time-delay) fuse: 175% max - Inverse-time circuit breaker: 250% max - Instantaneous-trip (MCP) breaker: 800% or 1300% (listed) max

Key Concepts

Hazardous Location Classification (Articles 500–503)

• Class I (Article 501): Flammable gases or vapors (e.g., gasoline, hydrogen). Division 1 = hazard present under normal conditions. Division 2 = hazard present only under abnormal conditions.
• Class II (Article 502): Combustible dust (e.g., grain, coal, metal dust). Groups E, F, G. Division 1 = dust in suspension normally. Division 2 = dust accumulations only.
• Class III (Article 503): Ignitible fibers/flyings (e.g., textile mills, sawmills). No groups assigned. Division 1 = fibers handled/manufactured. Division 2 = fibers stored.
• Zone system (Articles 505/506): Alternative to Division system. Zones 0/1/2 for gases; Zones 20/21/22 for dust. Zone 0 is more restrictive than Division 1.

Protection Techniques (500.7)