Alabama NASCLA Journey-level Electrician Exam

Key Concepts

Switch outlet symbols — Ugly's Electrical References 2023, Page 125 (Electrical Symbols). Switch outlets are the letter S with a subscript: - S (no subscript) = single-pole switch - S₂ = double-pole switch - S₃ = three-way switch - S₄ = four-way switch - S_D = door switch - S_F = fused switch; S_WPF = weather-proof fused switch

Other listed subscripts include S_E (electrolier), S_P (switch and pilot lamp), S_K (key-operated), S_CB (circuit breaker), S_WCB (weather-proof circuit breaker), S_MC (momentary-contact), S_RC (remote-control), and S_WP (weather-proof switch).

Wiring symbols — Page 126. On a home run, the number of arrows equals the number of circuits. Conductor quantity is shown separately by cross (tick) marks on the wiring line. Page 126 also shows transformers (iron core, air, dual voltage, auto, current), AC and DC motors, resistors (fixed, adjustable by…

Key Concepts

Arc flash - The arc flash boundary is the distance at which incident energy equals 1.2 cal/cm² (5 J/cm²) — NFPA 70E 130.5(E)(1). That same value is the threshold incident energy for a second-degree burn [130.7(C)(6)]. - Arc flash PPE is selected by either the incident energy analysis method or the arc flash PPE category method — "Either, but not both, methods shall be permitted to be used on the same piece of equipment" [130.5(F)]. - The incident energy analysis must be updated when distribution system changes could affect results, and reviewed for accuracy at intervals not to exceed 5 years [130.5(G)]. Label data is likewise reviewed at intervals not to exceed 5 years [130.5(H)]. - Equipment labels must show nominal system voltage, arc flash boundary, and at least one of: available incident energy with working distance…

Key Concepts

Ohm's Law. Current is directly proportional to voltage and inversely proportional to resistance (Theory 12.6(A)). The three transpositions are I = E/R, E = I × R, and R = E/I (Theory 12.6(B) and 12.7, Ohm's Law Formula Circle; Ugly's Electrical References, 2023 ed., Ohm's Law, Page 1). To use the Formula Circle, place your finger on the unknown; the two remaining variables show the formula.

Proportionality. Current increases in direct proportion to a voltage increase if resistance stays the same (12.6(A)(1)). Current decreases in direct proportion to a resistance increase if voltage stays the same (12.6(A)(2)).

Utilization voltages. Residential lights and receptacles operate at 120V; ranges, dryers, and air-conditioning equipment at 120/240V or 240V (12.3(A)(1)). In commercial and industrial occupancies the voltage is often 277V for lighting and 480V for motors and air-conditioning units (12.3(A)(2)).

Key Concepts

Verifying absence of voltage - Test instruments used to test for absence of voltage on conductors or circuit parts operating at 50 volts or more must be verified on a known voltage source both before and after the test — NFPA 70E 110.6(E). - The process for establishing and verifying an electrically safe work condition has steps that must be performed in the order presented, if feasible — 120.6. Step (7) requires an adequately rated portable test instrument at each point of work, testing each phase conductor both phase-to-phase and phase-to-ground. - Exception No. 1 to (7): an adequately rated permanently mounted absence of voltage tester, listed and labeled for the purpose, may be used. Exception No. 2 to (7): noncontact capacitive test instruments are permitted to test each phase conductor **only on electrical systems over 1000…

Key Concepts

Purpose, scope, arrangement (Article 90). The Code's purpose 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(A)). Chapters 1–4 apply generally; Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions and may supplement or modify the requirements in Chapters 1 through 7; Chapter 8 (communications) is not subject to Chapters 1–7 except where specifically referenced; Chapter 9 is tables applicable as referenced (90.3). The AHJ interprets the rules, approves equipment, and grants special permission (90.4(B)), and may waive requirements or permit alternative methods by special permission (90.4(C)). Mandatory rules use shall/shall not; permissive rules use shall be permitted / shall not be required (90.5(A), (B)). Limiting the number of circuits in…

Key Concepts

Branch circuits (Article 210) - Where a branch circuit supplies continuous loads, the OCPD rating shall be not less than 125 percent of the continuous load — 210.20(A). - Informational Note to 210.19: conductors sized to prevent a voltage drop exceeding 3 percent at the farthest outlet; maximum total drop on feeders and branch circuits should not exceed 5 percent. - AFCI protection applies to 120-volt, single-phase, 10-, 15-, and 20-ampere branch circuits supplying outlets or devices in kitchens, bedrooms, family rooms, living rooms and similar areas of dwelling units — 210.12(B). - Table 210.3 points to 440.6, 440.31, and 440.32 for air-conditioning and refrigerating equipment branch circuits.

Key Concepts

• Box fill is a volume calculation. Add the volumes from 314.16(B)(1) through (B)(6); no allowance is required for small fittings such as locknuts and bushings (NEC 2023, 314.16(B)).
• Conductor fill: each conductor originating outside and terminating/spliced in the box counts once; each pass-through conductor counts once (314.16(B)(1)).
• Clamps: one allowance total for all internal clamps, based on the largest conductor in the box (314.16(B)(2)).
• Luminaire studs/hickeys: a single allowance for each type of fitting, based on the largest conductor in the box (314.16(B)(3)).
• Devices: a double allowance for each yoke or strap, based on the largest conductor connected to that yoke (314.16(B)(4)).
• EGCs: one allowance for up to four; ¼ allowance for each additional EGC (314.16(B)(5)).
• Conduit bodies enclosing 6 AWG or smaller shall have a cross-sectional area **not less…

Key Concepts

Motor conductor sizing (Article 430, Part II) - A single continuous-duty motor's conductors: ampacity not less than 125% of the motor full-load current (FLC) determined by 430.6(A)(1) — 430.22. - Conductor ampacity, switch ratings, and branch-circuit short-circuit/ground-fault (SC/GF) device ratings come from Table 430.247–430.250 values, not nameplate; nameplate current is used for separate overload protection — 430.6(A)(1) and (A)(2). - Wye-start, delta-run: line side of controller 125%; conductors between controller and motor not less than 72% of FLC (58% × 1.25) — 430.22(C). Part-winding: 62.5% (50% × 1.25) — 430.22(D). - DC motor on rectified single-phase supply, rectifier output to motor: 190% (half-wave), 150% (full-wave); rectifier input conductors 125% of rated input current — 430.22(A). - Other than continuous duty: use Table 430.22(E) percentages of nameplate current (intermittent duty, 30- and 60-minute rated motor = 90%). -…

Key Concepts

Hazardous location classification (Art. 500) - Group D: flammable gas/vapor with MESG greater than 0.75 mm or MIC ratio greater than 0.80; typical material is propane [500.6(A)(4)]. Group C is MESG >0.45 mm and ≤0.75 mm (ethylene); Group B is MESG ≤0.45 mm (hydrogen); Group A is acetylene. - Group E: combustible metal dusts — aluminum, magnesium, and their commercial alloys [500.6(B)(1)]. Group F: carbonaceous dusts; Group G: flour, grain, wood, plastic, chemicals. - Locations where ignitible fibers/flyings are handled, manufactured, or used are Class III, Division 1 (cotton and other textile mills) [500.5(D)(1)(b)].

Key Concepts

Class 1 circuits (NEC Article 724) - Class 1 circuits shall be supplied from a source with a rated output of not more than 30 volts and 1000 volt-amperes (724.40). - Power sources other than transformers shall be protected by overcurrent devices rated not more than 167 percent of the volt-ampere rating of the source divided by the rated voltage; VAmax is limited to 2500 volt-amperes, and Imax × Vmax shall not exceed 10,000 volt-amperes (724.40(B)). - Overcurrent protection for 14 AWG and larger follows conductor ampacity without ampacity adjustment/correction factors; it shall not exceed 7 amperes for 18 AWG and 10 amperes for 16 AWG (724.43). - Conductor insulation shall be rated for system voltage and not less than 600 volts (724.49(B)).