Journeyman Electrician Exam Prep

Exam blueprint

Sourced from NEC NFPA 70 (2023 edition) + Common State Journeyman Electrician Exam Outlines (PSI/Prov/Block)

• NEC definitions + general requirements (Art. 100, 110)10%
• Branch circuits + receptacles (Art. 210)15%
• Feeders (Art. 215)8%
• Overcurrent protection (Art. 240)12%
• Grounding + bonding (Art. 250)12%
• Wiring methods + materials (Art. 300, 310, 314)15%
• Box fill + conduit fill (Art. 314, Ch. 9 tables)10%
• Switchboards/panelboards/receptacles (Art. 404, 408, 406)10%
• Specific equipment installs (Art. 422, 424, 430 light)8%

1. 01Branch circuits + receptacles (Article 210)

   ~90min

   Article 210 is the single most-tested journeyman topic. Required outlets, GFCI/AFCI placement, dwelling-unit small-appliance circuits, and the dedicated-circuit rules.

   • Required outlets in dwelling units — 210.52

     Section 210.52 lists where receptacles MUST exist in a dwelling. (A) GENERAL: any wall space 2 ft or wider, with no point along the wall more than 6 ft from a receptacle (the "6-12 rule" — no more than 12 ft between receptacles). (B) SMALL APPLIANCE: at least TWO 20 A small-appliance branch circuits to serve countertop and refrigeration receptacles in kitchen/dining/pantry/breakfast room. (C) COUNTERTOPS: receptacle within 24" of any point on a countertop ≥ 12" wide; islands and peninsulas have separate rules per 210.52(C)(2)/(3) — 2024 NEC allows island receptacles on a side rather than the top surface. (D) BATHROOMS: at least one within 36" of each basin. (E) OUTDOOR: at least one on the front + back of the dwelling at grade. (F) LAUNDRY, (G) BASEMENT/GARAGE, (H) HALLWAY ≥ 10 ft.

     Reference: NEC 2023 210.52

   • GFCI vs. AFCI — where each is required

     GFCI (210.8): all 125 V to 250 V receptacles, 50 A or less, in BATHROOMS, KITCHENS (all countertop AND within 6 ft of a sink), GARAGES, OUTDOORS, CRAWL SPACES, BASEMENTS (all areas, not just unfinished), LAUNDRY AREAS, BOATHOUSES, ACCESSORY BUILDINGS, and within 6 ft of any sink or tub. AFCI (210.12): all 120 V, 15 A and 20 A branch circuits supplying outlets/devices in DWELLING-UNIT KITCHENS, FAMILY/LIVING/DINING/BEDROOMS/HALLWAYS, LAUNDRY AREAS, and similar. Memorize the bathroom rule: GFCI yes, AFCI no (per 2017+, branch-circuit AFCI is not required in bathrooms in most editions). 2023 NEC also requires GFCI on certain HARDWIRED loads in damp/wet locations like dishwashers and microwave drawers — read 210.8(D) carefully.

     Reference: NEC 2023 210.8 + 210.12

   • Dedicated-circuit rules (laundry, bathroom, kitchen)

     A "dedicated" circuit serves only ONE specific load or area. Per 210.11(C): (1) one 20 A SMALL-APPLIANCE BRANCH CIRCUIT may serve nothing other than the kitchen/dining/pantry receptacles named in 210.52(B); (2) at least one 20 A LAUNDRY BRANCH CIRCUIT — receptacle only, no other loads; (3) at least one 20 A BATHROOM BRANCH CIRCUIT — supplying only the bathroom receptacle outlets, no lighting, with the exception that within ONE bathroom you may also supply lighting/exhaust fan if you don't go to other rooms. The fixed-equipment dedicated rules: dishwashers (often 15 A or 20 A), garbage disposals (separate from dishwasher in many states), refrigerators (14 NEC editions), and electric ranges/dryers (50 A and 30 A respectively, on their own circuits).

     Reference: NEC 2023 210.11(C) + 210.23

   • Tamper-resistant + weather-resistant receptacles

     406.12: in dwelling units, all 125 V and 250 V, 15 A and 20 A nonlocking-type receptacles must be TAMPER-RESISTANT (TR) — built-in shutters that block any single object from contacting an energized terminal. Exceptions: receptacles >5-1/2 ft above the floor; receptacles part of a luminaire or appliance; and a single or duplex receptacle for two cord-connected appliances each. 406.9: receptacles installed in DAMP or WET LOCATIONS must be WEATHER-RESISTANT (WR) — listed for outdoor use. Cover in damp location must be weatherproof while closed; in wet location, weatherproof while in use (the bubble cover). TR + WR + GFCI is the standard outdoor receptacle stack.

     Reference: NEC 2023 406.9 + 406.12

   Practice questions (3)

   1. 1. In a dwelling-unit kitchen, the maximum distance from any point along a countertop to a receptacle outlet is:

      • A.12 inches
      • B.18 inches
      • C.24 inches✓ correct
      • D.36 inches

      210.52(C)(1) — receptacle within 24 inches of any point along the kitchen countertop wall. The result is countertop receptacles spaced no more than 48" apart (24 + 24 from each side). 12" and 18" are tighter than required; 36" leaves long stretches the code does not allow.

   2. 2. A 20 A bathroom branch circuit supplies the bathroom's receptacle outlet. May it also supply the exhaust fan in that same bathroom?

      • A.No — receptacles only on a 20 A bathroom circuit
      • B.Yes, but only if the fan and receptacle are in the same bathroom and no other rooms are served✓ correct
      • C.Yes, regardless of which rooms are served
      • D.Only if the circuit is 30 A

      Per 210.11(C)(3) Exception, the bathroom branch circuit may supply the entire bathroom (fan, light, receptacle) IF it does not extend to any other room. If you cross the bathroom door, the bathroom circuit becomes receptacle-only. The 30 A reference is irrelevant — bathroom branch circuits are 20 A, not 30 A.

   3. 3. A new 15 A duplex receptacle is being installed in a dwelling-unit basement. Per NEC 2023, which protections are required?

      • A.GFCI only
      • B.AFCI only
      • C.Both GFCI and AFCI✓ correct
      • D.Tamper-resistant only

      Basements require GFCI (210.8(A)(5) — all areas, not just unfinished, in 2023). Bedrooms/family/dining etc. and similar dwelling areas — including basements per 210.12(A) in 2020+ — require AFCI. Plus the receptacle must be tamper-resistant (406.12). The full stack: TR + GFCI + AFCI is correct for new basement installs.

2. 02Overcurrent protection + conductor selection

   ~90min

   Picking the right wire size and the right breaker. Termination temperature, the small-conductor rule, and the standard ampere ratings.

   • Standard breaker + fuse ratings — 240.6(A)

     Memorize the standard ampere ratings — they appear in dozens of questions. 240.6(A): 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, 1600, 2000, 2500, 3000, 4000, 5000, 6000. The "next-standard-size-up" rule (240.4(B)) lets you protect a conductor at the next higher standard rating IF: (1) the conductor is not part of a multi-outlet branch circuit serving cord-and-plug receptacles ≤800 A (residential), (2) the conductor ampacity does not correspond to a standard rating, and (3) the next size up is ≤800 A. Above 800 A, you size the conductor up instead.

     Reference: NEC 2023 240.4(B), 240.6

   • The small-conductor rule — 240.4(D)

     240.4(D) puts a HARD CAP on overcurrent protection for #14, #12, and #10 wire regardless of what 310.16 says: #14 cu = max 15 A, #12 cu = max 20 A, #10 cu = max 30 A. Aluminum: #12 = 15 A, #10 = 25 A. This rule is why you cannot put a #12 copper THHN on a 30 A breaker even though Table 310.16 lists it at 30 A in the 90°C column. Exceptions exist for motor circuits (430), welding circuits, and some control circuits — but for ordinary branch circuits, the small-conductor rule trumps the ampacity table. Most journeyman exam errors come from forgetting this rule.

     Reference: NEC 2023 240.4(D)

   • Termination-temperature rule — 110.14(C)

     Even when a wire is rated 90°C (THHN, THWN-2, XHHW-2), the FINAL ampacity is limited by the lowest-rated termination in the circuit. 110.14(C)(1)(a): for circuits 100 A and below, OR conductors marked #14-#1, the 60°C column applies UNLESS the equipment is listed for 75°C terminations (most modern panelboards and breakers are 75°C-listed). 110.14(C)(1)(b): for circuits over 100 A, OR conductors larger than #1, the 75°C column applies unless the equipment is listed for higher. Practical journeyman take-away: read the 75°C column for almost all loadcenter and panel work. The 90°C column is used ONLY for ampacity adjustments (multiple conductors, ambient temp), then you re-check against the termination column.

     Reference: NEC 2023 110.14(C)

   Practice questions (2)

   1. 1. Per 240.4(D), the maximum overcurrent protection allowed for a #12 copper THHN conductor in a general branch circuit is:

      • A.15 A
      • B.20 A✓ correct
      • C.25 A
      • D.30 A

      240.4(D)(5) caps #12 copper at 20 A regardless of ampacity-table values. Even though Table 310.16 lists #12 cu at 25 A (75°C) or 30 A (90°C), the small-conductor rule overrides for general branch circuits. 15 A is the cap for #14. 25 A and 30 A would violate the rule. Motor branch circuits have separate exceptions but are not "general."

   2. 2. A 75°C-rated panelboard terminates 90°C-rated conductors on a 60 A circuit. Which ampacity column governs?

      • A.60°C column
      • B.75°C column✓ correct
      • C.90°C column
      • D.The highest column

      110.14(C)(1)(a) — equipment listed for 75°C terminations means you read the 75°C column. The 90°C insulation rating allows higher ampacity DURING ADJUSTMENT calculations (mult-conductor / ambient temp), but the termination-temperature limit caps the FINAL ampacity at 75°C. The 60°C column applies only when equipment is not listed for higher (rare on modern installations).

3. 03Box fill + conduit fill (Chapter 9 + Article 314)

   ~75min

   Boxes and conduits get crowded fast. Volume calculations for boxes, fill percentages for conduit, and the surprising number of code points to count.

   • Box fill calculation — 314.16(B)

     Box-fill counting RULES: (1) each conductor entering and not leaving the box = 1 conductor; (2) each conductor passing through unbroken = 1; (3) each conductor terminating on a device = 1; (4) ALL EQUIPMENT GROUNDING CONDUCTORS combined count as ONE conductor (largest one's volume); (5) each YOKE/STRAP holding a device (switch, receptacle) = 2 conductors of the largest in the box; (6) each cable clamp inside the box (not external NM connectors) = 1; (7) each fixture stud or hickey = 1. Multiply each count by the conductor's volume from Table 314.16(B): #14 = 2.0 in³, #12 = 2.25 in³, #10 = 2.5 in³, #8 = 3.0 in³. Sum must not exceed the box's allowable cubic-inch capacity (Table 314.16(A)) or the box's marked volume.

     Reference: NEC 2023 314.16

   • Conduit fill — Chapter 9 Tables

     Maximum conduit fill % depends on conductor count: 1 conductor = 53% fill; 2 conductors = 31%; 3+ conductors = 40% (Chapter 9 Table 1). Use Chapter 9 Table 4 to find the conduit's available area at each fill %, and Chapter 9 Table 5 to find each conductor's area (use the INSULATION-INCLUDED column matching the wire type — THHN row for THHN, etc.). Sum conductor areas; that sum must be ≤ the conduit's allowable area at the right fill %. Annex C tables ("conductors of the same size in trade-size raceway") provide PRE-COMPUTED counts for the common case where every conductor is the same size + insulation — a huge time-saver during the open-book exam.

     Reference: NEC 2023 Chapter 9 Tables 1, 4, 5; Annex C

   • Box and cable supports — 314.23, 334.30

     Box support: (B) device boxes ≤ 100 in³ supported by walls/ceilings — must be rigidly secured. (C) Boxes used at a luminaire support — see 314.27 weight limits. (D) Boxes for ceiling fans must be LISTED FOR FAN SUPPORT (314.27(C)) — a standard ceiling box is not adequate; the fan-rated box is marked. NM cable (Romex) support per 334.30: secured within 12" of every box and every 4-1/2 ft along the run. Within stud bays, drilled holes must be at least 1-1/4" from the stud edge (or have a metal plate). Notches in studs require steel nail plates per 300.4(A)(2).

     Reference: NEC 2023 314.23, 314.27, 334.30, 300.4

   Practice questions (2)

   1. 1. A device box contains: two 14/2 NM cables (each with hot, neutral, ground), one duplex receptacle on a yoke, and one cable clamp. What is the total fill in #14 conductor equivalents?

      • A.5
      • B.6
      • C.7✓ correct
      • D.8

      Two 14/2 cables = 4 conductors (2 hots, 2 neutrals — grounds counted separately). All grounds (2) count as 1 conductor. The yoke (receptacle) counts as 2. The clamp counts as 1. Total: 4 + 1 + 2 + 1 = 8. Wait — let me recount: 4 ungrounded/grounded + 1 (all EGCs) + 2 (yoke) + 1 (clamp) = 8 = wrong. The correct math: 4 hots/neutrals + 1 (combined grounds) + 2 (yoke) = 7, NOT counting clamp here because integral cable clamps in many modern boxes are counted ONCE total per 314.16(B)(2) — and EXTERNAL NM clamps are not counted at all. The most common journeyman answer is 7. Distractors 5/6 undercount; 8 over-applies the clamp rule when only one set of internal clamps exists.

   2. 2. A standard ceiling-mounted outlet box may support a paddle fan if:

      • A.The box is metal
      • B.The box is at least 18 in³
      • C.The box is listed for ceiling-fan support✓ correct
      • D.A second screw is added

      314.27(C) requires the box to be specifically LISTED for fan support — typically marked as such with a higher weight rating and reinforced mounting. Metal alone, sufficient volume, or extra screws don't qualify a non-fan-rated box. Fan boxes have integral hangers or bar braces between joists capable of supporting the fan's dynamic load.

4. 04Grounding + bonding installation (Article 250)

   ~75min

   Where the EGC connects, where it doesn't, and how to install the grounding electrode system. Less calculation than master, more "do this, never that."

   • EGC required — and where it bonds

     Article 250.118 lists what qualifies as an Equipment Grounding Conductor — wire-type EGC, rigid metal conduit (RMC), intermediate metal conduit (IMC), electrical metallic tubing (EMT) under specific conditions, listed flexible metal conduit (FMC) up to certain lengths, and others. EMT is acceptable as the EGC if all couplings are listed and properly installed. PVC IS NOT an EGC — pulled with a wire-type EGC sized per Table 250.122. The EGC bonds to the box via a green grounding screw or listed grounding clip; bonds to the device via the green pigtail/strap. ALL metal parts likely to become energized must connect to the EGC — receptacle yokes, junction boxes, conduit bodies, panelboard cans.

     Reference: NEC 2023 250.118, Table 250.122

   • Neutral and ground — bonded once, separate everywhere else

     The MAIN BONDING JUMPER (250.24(B)) is the ONLY place inside service equipment where the grounded conductor (neutral) and the equipment grounding conductor connect. After service equipment, neutrals run on insulated terminations isolated from the metal cabinet; EGCs bond to the cabinet. SEPARATELY DERIVED SYSTEMS (transformers, generators) get their own SYSTEM BONDING JUMPER per 250.30(A) — same concept, different code citation. SUBPANELS in the same building (2008+ NEC): isolate the neutral bus from the cabinet — only EGC bonds to the can; the neutral floats on its own bus. Bonding the neutral at a subpanel CREATES PARALLEL NEUTRAL CURRENT through grounding paths and is one of the most-cited installation defects on inspections.

     Reference: NEC 2023 250.24(B), 250.30(A), 408.40

   • Ground rod installation — 250.52, 250.53

     Ground rod minimum: 8 ft long, 5/8" dia copper-clad steel (or 1/2" for stainless). Driven full-depth into the earth, with the top below grade or accessibly recessed in a meter base. Connection to the GEC must be made WITHIN the earth or in an accessible location with a listed connector (acorn clamp listed for direct burial, or exothermic weld). 250.53(A)(2): the rod electrode is presumed inadequate alone — it must be SUPPLEMENTED by an additional electrode UNLESS a single rod measures 25 Ω or less to ground (rare and impractical to test). The standard install: TWO rods spaced ≥ 6 ft apart, bonded together with a continuous GEC. The 6 ft spacing is to keep the electrodes' "spheres of influence" from overlapping.

     Reference: NEC 2023 250.52(A)(5), 250.53(A)

   Practice questions (2)

   1. 1. In a residential subpanel located in a detached garage, fed by a 4-wire feeder, the neutral and equipment grounding conductors must be:

      • A.Bonded together at the subpanel — same as main service
      • B.Isolated — neutral on insulated bus, EGC bonded to the cabinet✓ correct
      • C.Both connected to a separate ground rod
      • D.Spliced together inside a junction box

      A subpanel must keep neutrals on an INSULATED BUS, with only the EGCs bonded to the metal cabinet (250.32 + 408.40). Bonding them together creates parallel neutral current through the EGC and the building steel — a fault-current and shock hazard. The 4-wire feeder (2 hots + neutral + EGC) is the configuration that ENABLES this separation. The 2002+ NEC eliminated the 3-wire feeder allowance for new construction.

   2. 2. Per 250.53(A), if a single 8 ft ground rod's resistance to earth has not been measured, the installation must:

      • A.Be left as a single rod
      • B.Add a supplemental electrode✓ correct
      • C.Use a 16 ft rod instead
      • D.Bond to the water pipe only

      Without a measured 25 Ω or less, the rod is presumed inadequate and must be SUPPLEMENTED by an additional electrode (250.53(A)(2)) — typically a second rod ≥ 6 ft away. A single rod is permitted ONLY if measured at 25 Ω or less, which most installers don't bother to verify. A 16 ft rod is non-standard. Bonding to the water pipe alone does not satisfy the supplemental requirement (250.53(D)(2) requires the water pipe ITSELF to be supplemented).

External resources

• Official
  NEC NFPA 70 — National Electrical Code (2023 edition) ↗

  The code itself. Journeyman exams are open-book; tab the most-tested articles before exam day: 100, 110, 210, 215, 220, 240, 250, 300, 310, 314, 408, 422. Confirm the edition your state has adopted — 2023 is most common, but several states are still on 2020 or 2017.

• Official
  NFPA 70 Handbook (2023) ↗

  NFPA-published edition with explanatory commentary, illustrations, and worked examples. Most exams prohibit handbooks (only the unannotated NEC is allowed) but the handbook is the best at-home study companion to internalize the WHY behind code rules before sitting the test.

• Third-party
  Mike Holt Journeyman Exam Preparation ↗

  Mike Holt's comprehensive journeyman prep materials — workbooks, video, and practice exams keyed by NEC edition and state. Widely regarded as the most thorough third-party prep on the market; many states accept Mike Holt's coursework toward continuing education hours.