Journeyman Electrician study guide
Journeyman Electrician · Work through your exam, one topic at a time.
The Journeyman Electrician credential is a state- or locally-issued license that certifies you to perform electrical installation work under the scope your jurisdiction defines, and it is usually the step between a trainee or apprentice classification and a master's license. It is aimed at electricians who have already accumulated the supervised field hours their licensing board requires and who can now demonstrate, on a written exam, that they can apply code rules to real installations. The Journeyman Electrician study guide has 10 sections and about 3,156 words.
01Electrical Theory, Ohm's Law, and Circuit Calculations
Nearly every calculation question reduces to Ohm's law (E = I × R) and the power wheel (P = E × I, P = I²R, P = E²/R), combined with the rules for series and parallel circuits. In series, current is identical everywhere and voltages add; in parallel, voltage is identical and branch currents add.
324 words, about 2 min02Wiring Methods and Materials
Chapter 3 of the NEC is organized one article per wiring method: 320 AC cable, 330 MC cable, 334 NM cable, 338 SE cable, 342 rigid metal conduit, 344 IMC, 348 FMC, 350 LFMC, 352 PVC, 358 EMT, 362 ENT. For each you must know three things: where it is permitted, where it is prohibited, and how it must be secured and supported.
312 words, about 2 min03Grounding, Bonding, and Ground-Fault Protection
Article 250 separates three ideas that questions deliberately blur. The grounded conductor (neutral) is a circuit conductor that carries current.
302 words, about 2 min04Overcurrent Protection and Short-Circuit Current Ratings
Overcurrent protective devices must have an ampere rating that protects the conductor, an interrupting rating at least equal to the available fault current, and a short-circuit current rating adequate for the equipment it protects. Standard device ratings (240.6) run 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200 A.
325 words, about 2 min05Branch Circuits, Feeders, and Service Load Calculations
Article 210 governs branch circuits, Article 215 feeders, Article 220 calculations, and Article 230 services. The single most tested rule is the continuous-load adder: branch-circuit and feeder conductors and overcurrent devices must be sized at 125 percent of the continuous load plus 100 percent of the noncontinuous load.
323 words, about 2 min06Conductors, Cables, Ampacities, and Derating
Ampacity comes from Table 310.16, which gives values in 60°C, 75°C, and 90°C columns for copper and aluminum. The column you may use is limited by 110.14(C): the lowest temperature rating of any terminating device in the circuit caps the usable ampacity, even when the conductor itself is rated higher.
312 words, about 2 min07Boxes, Raceways, Panelboards, and Equipment Installation
Box fill (314.16) is a volume calculation. Each conductor counts once; each cable clamp counts as one conductor of the largest size; each device or strap counts as two conductors of the largest size attached; one or more equipment grounding conductors count as a single conductor of the largest EGC.
386 words, about 2 min08Motors, Transformers, HVAC, and Control Circuits
Motor calculations use tables, not nameplate current. Article 430 gives full-load current from Tables 430.248 (single-phase) and 430.250 (three-phase).
272 words, about 1 min09Special Occupancies, Special Equipment, and Hazardous Locations
Articles 500 through 506 define classified locations. Class I is flammable gas or vapor, Class II is combustible dust, Class III is ignitable fibers.
292 words, about 1 min10Electrical Safety, Tools, and Jobsite Practices
NFPA 70E is the practical companion to the NEC. It establishes shock hazard approach boundaries - limited, restricted, and prohibited - measured from the live part, and the arc flash boundary based on incident energy.
308 words, about 2 min