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JOURNEYMAN NEC 2023

Journeyman Electrician Practice Test 4

This is Journeyman Electrician Practice Test 4 — a free, exam-style practice test based on the 2023 NEC. The 30 questions follow the PSI journeyman exam outline: concrete-encased electrodes, parallel EGCs, commercial receptacle and show-window loads, feeder taps, motor feeder protection, working-space entrances, fire pumps, signs, marinas and commercial garages. You need 70% or higher to pass. Every question includes the NEC reference and a step-by-step explanation.

How this test works

Read each question carefully

Look for absolute words like always / never — they often distinguish the right answer.

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You have 75 min for 30 questions. Skip tough ones and come back.

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Frequently Asked Questions

Yes — completely free with no account required. All questions include detailed explanations and NEC references.

Most state Journeyman exams have 80–100 questions covering NEC code, wiring methods, branch circuits, motor controls, and load calculations.

Most states require a 70–75% passing score. This practice test uses the same 70% pass threshold so you know where you stand.

Questions are written to the 2023 NEC. Check your state licensing board to confirm which edition your state has adopted.

Before You Start

30 questions — multiple choice
36 minutes to finish
Pass score is 70% — you need 17 or more correct answers
You will see the full answer and NEC reference after you submit

What This Test Covers

Basic electrical theory — Ohm's Law, voltage, current, and resistance
How to measure current — ammeter connected in series
NEC definitions — concealed conductor, festoon lighting, and more (Article 100)
Lamp spacing from combustible materials (NEC 600.9)
Emergency circuits — wiring rules (NEC 700.10)
PVC conduit burial depth (NEC 515.8)
Overhead service conductor minimum size (NEC 230.23)
Conductor ampacity correction for high temperature
Wet location enclosure type required (NEC 312.2)
Panelboard maximum load rating (NEC 408.30)
Single family dwelling service entrance minimum rating (NEC 230.42)
Lighting fixture weight limit on screw shell (NEC 410.30)
Small motor controller rule (NEC 430.81)
EMT conduit — maximum bends between pull points (NEC 358.26)
Neutral conductor color code (NEC 200.6)
NM cable — where it cannot be used (NEC 334.12)
Working space in front of electrical panel (NEC 110.26)
Voltage drop and electricity cost calculations

Tip: Read each question carefully. Some questions use True or False — make sure you pick the right one.

Questions

75 min

Time

70%

Pass

Timer starts immediately. Progress is auto-saved.

Journeyman Electrician Practice Test 4 — Question List

Question 1: A concrete-encased electrode made of at least 20 ft of 1/2 in. rebar must be encased by at least how much concrete?

1 in.
2 in.
3 in.
4 in.

NEC Reference: NEC 250.52(A)(3)

Question 2: A 600 kcmil copper service has a grounding electrode conductor that runs only to a concrete-encased electrode. What is the largest copper GEC the NEC requires for that connection?

2/0 AWG
1/0 AWG
4 AWG
6 AWG

NEC Reference: NEC 250.66(B)

Question 3: An existing 480-volt, 3-phase, 3-wire delta system is intentionally left ungrounded. What does the NEC require for this system?

Ground detectors installed on the system
Nothing, ungrounded systems have no special requirements
A neutral derived with a zig-zag transformer
A grounding resistor sized for 1,200 A

NEC Reference: NEC 250.21(B)

Question 4: When is a bonding jumper from a metal box to the receptacle grounding terminal NOT required?

When the box is surface-mounted and the yoke has direct metal-to-metal contact with the box
When the flush box is installed in drywall and the receptacle mounting screws are steel
When the receptacle is mounted on a raised cover that is attached to a flush-mounted box
When the branch circuit supplying the receptacle is protected by a GFCI circuit breaker

NEC Reference: NEC 250.146(A)

Question 5: A 1,200-ampere feeder is run as three parallel sets in three separate raceways. What size copper equipment grounding conductor is required in each raceway?

1/0 AWG
2/0 AWG
3/0 AWG
250 kcmil

NEC Reference: NEC 250.122(F)

Question 6: An office building has 60 general-purpose duplex receptacle outlets. What is the demand load for these receptacles?

9,000 VA
10,400 VA
10,800 VA
12,000 VA

NEC Reference: NEC 220.14(I) and Table 220.44

Question 7: A heater rated 1,500 W at 120 V is mistakenly connected to 240 V. Assuming its resistance does not change, how much power does it now produce?

750 W
1,500 W
3,000 W
6,000 W

Question 8: A store has 30 linear feet of show window. What minimum load must be included for the show window lighting?

3,600 VA
5,400 VA
6,000 VA
9,000 VA

NEC Reference: NEC 220.14(G)

Question 9: A one-family dwelling has an attached two-car garage with two vehicle bays. What is the minimum number of receptacle outlets required in the garage under 210.52(G)(1)?

NEC Reference: NEC 210.52(G)(1)

Question 10: In which location is a service disconnecting means NOT permitted?

In a basement near where the service conductors enter
In a garage near where the service conductors enter
On the outside wall of the building
In a bathroom

NEC Reference: NEC 230.70(A)(2)

Question 11: Two single-pole breakers supply a multiwire branch circuit in a dwelling. What must be provided at the panelboard?

A means, such as an identified handle tie or a 2-pole breaker, that simultaneously disconnects all ungrounded conductors
A separate neutral for each breaker
A GFCI breaker on each leg
Nothing, if the breakers are adjacent

NEC Reference: NEC 210.4(B)

Question 12: Unused openings in boxes, raceways, cabinets and equipment enclosures (other than those for mounting or drainage) must be:

Covered with electrical tape
Closed only if they are larger than 1/2 in.
Left open for ventilation
Closed with protection approximately equivalent to the wall of the equipment

NEC Reference: NEC 110.12(A)

Question 13: A 1,600-ampere switchboard is 8 ft wide. How many entrances to and egress from its working space are required (absent a continuous, unobstructed way out or double working space)?

One entrance, at least 24 in. wide
No entrance requirement applies
Two entrances on the same end
One entrance at each end of the working space

NEC Reference: NEC 110.26(C)(2)

Question 14: Resistors of 10 Ω, 20 Ω and 30 Ω are connected in series across 120 volts. What is the voltage drop across the 30 Ω resistor?

20 V
40 V
60 V
120 V

Question 15: On a 4-wire, 3-phase wye feeder, when must the neutral be counted as a current-carrying conductor for ampacity adjustment?

When the major portion of the load is nonlinear (such as electronic equipment)
Only when the neutral is smaller than the phase conductors
Never
Always

NEC Reference: NEC 310.15(E)(3)

Question 16: Type NM-B cable has 90 °C rated conductors. What temperature rating sets the final ampacity of NM cable?

60 °C
The rating of the panelboard lugs
75 °C
90 °C

NEC Reference: NEC 334.80

Question 17: A cable is installed under metal-corrugated sheet roof decking. What is the minimum distance from the nearest surface of the roof decking to the cable?

2 in.
1½ in.
1¼ in.
3/4 in.

NEC Reference: NEC 300.4(E)

Question 18: Unless specifically permitted elsewhere in the Code, the maximum overcurrent protection for 14 AWG copper conductors is:

10 A
15 A
20 A
25 A

NEC Reference: NEC 240.4(D)(3)

Question 19: A field-installed 10 ft feeder tap leaves the enclosure in which the tap is made. The feeder is protected at 600 A. What minimum ampacity must the tap conductors have, apart from the load they supply?

200 A
100 A
60 A
40 A

NEC Reference: NEC 240.21(B)(1)

Question 20: A feeder supplies three 460-volt, 3-phase motors: 30 hp (40 A), 15 hp (21 A) and 10 hp (14 A). The 30 hp motor branch circuit is protected by a 100 A inverse time breaker. What is the maximum standard rating of the feeder breaker?

110 A
125 A
135 A
150 A

NEC Reference: NEC 430.62(A)

Question 21: What is the minimum ampere rating of the disconnecting means for a 20 hp, 460-volt, 3-phase motor?

54 A
33.75 A
31.05 A
27 A

NEC Reference: NEC 430.110(A)

Question 22: Each commercial occupancy accessible to pedestrians must have at least one sign outlet supplied by a branch circuit rated at least:

15 A, and it may supply other loads
20 A, and it supplies no other load
30 A, and it supplies no other load
20 A, and it may also supply the entrance lighting

NEC Reference: NEC 600.5(A)

Question 23: During motor starting, the voltage at the fire pump controller line terminals must not drop more than what percentage below normal?

NEC Reference: NEC 695.7(A)

Question 24: In a major repair garage without the ventilation specified in Article 511, the area from the floor up to what height is classified as Class I, Division 2?

6 in.
12 in.
18 in.
36 in.

NEC Reference: NEC 511.3

Question 25: At a marina, receptacles that provide shore power for boats must have individual ground-fault protection of equipment set to open at not more than:

5 mA
30 mA
100 mA
1,200 A

NEC Reference: NEC 555.35(A)(1)

Question 26: A permanently connected 4.5 kW water heater is supplied from a panelboard in another room. When may its branch-circuit breaker serve as the disconnecting means?

Only when the breaker is a GFCI type, because water heaters are in damp locations
Never; a separate disconnect switch must always be installed next to the water heater
Only when the appliance is rated 300 VA or less, regardless of the breaker location
When the breaker is within sight of the appliance or is lockable in the open position

NEC Reference: NEC 422.31(B)

Question 27: In a bathroom, a switch controls the lighting load. Which conductor must generally be provided at the switch location?

The grounded (neutral) conductor
A Class 2 control conductor
A 10 AWG equipment grounding conductor
A second ungrounded conductor

NEC Reference: NEC 404.2(C)

Question 28: Straight runs of 1 in. rigid metal conduit made up with threaded couplings may be supported at intervals not exceeding what distance (where supports prevent transmission of stresses to terminations)?

10 ft
12 ft
14 ft
16 ft

NEC Reference: NEC Table 344.30(B)(2)

Question 29: A box containing a receptacle is supported only by the conduits entering it. What is required?

This method is not permitted for boxes with devices
One conduit, secured within 3 ft
Two conduits, each secured within 5 ft
Two or more conduits threaded wrenchtight into the box, each secured within 18 in. of the box

NEC Reference: NEC 314.23(F)

Question 30: The ampacity of the conductors from the output terminals of a generator to the first distribution device containing overcurrent protection must be at least what percentage of the generator nameplate current rating?

150%
125%
115%
100%

NEC Reference: NEC 445.13(A)

Key NEC References for This Test

Article	What It Covers
Art. 100	Definitions — know: feeder, branch circuit, OCPD, dwelling unit
Art. 210	Branch Circuits — GFCI/AFCI locations, circuit ratings, outlet spacing (most tested)
Art. 220	Load Calculations — dwelling unit standard method
Art. 250	Grounding & Bonding — GEC sizing, electrode system, EGC
Art. 310	Conductors — ampacity (Table 310.12), insulation, derate rules
Art. 430	Motors — conductor 125% FLA, OCPD 250% FLA, overloads, disconnects

Study Tip: Tab Articles 210, 250, and 430 in your NEC before the exam. Know the Table 310.12 ampacity values for 14, 12, 10, 8, 6, and 4 AWG copper.

Journeyman Electrician Practice Test 4

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Journeyman Electrician Practice Test 4 — Question List

Question 1: A concrete-encased electrode made of at least 20 ft of 1/2 in. rebar must be encased by at least how much concrete?

Question 2: A 600 kcmil copper service has a grounding electrode conductor that runs only to a concrete-encased electrode. What is the largest copper GEC the NEC requires for that connection?

Question 3: An existing 480-volt, 3-phase, 3-wire delta system is intentionally left ungrounded. What does the NEC require for this system?

Question 4: When is a bonding jumper from a metal box to the receptacle grounding terminal NOT required?

Question 5: A 1,200-ampere feeder is run as three parallel sets in three separate raceways. What size copper equipment grounding conductor is required in each raceway?

Question 6: An office building has 60 general-purpose duplex receptacle outlets. What is the demand load for these receptacles?

Question 7: A heater rated 1,500 W at 120 V is mistakenly connected to 240 V. Assuming its resistance does not change, how much power does it now produce?

Question 8: A store has 30 linear feet of show window. What minimum load must be included for the show window lighting?

Question 9: A one-family dwelling has an attached two-car garage with two vehicle bays. What is the minimum number of receptacle outlets required in the garage under 210.52(G)(1)?

Question 10: In which location is a service disconnecting means NOT permitted?

Question 11: Two single-pole breakers supply a multiwire branch circuit in a dwelling. What must be provided at the panelboard?

Question 12: Unused openings in boxes, raceways, cabinets and equipment enclosures (other than those for mounting or drainage) must be:

Question 13: A 1,600-ampere switchboard is 8 ft wide. How many entrances to and egress from its working space are required (absent a continuous, unobstructed way out or double working space)?

Question 14: Resistors of 10 Ω, 20 Ω and 30 Ω are connected in series across 120 volts. What is the voltage drop across the 30 Ω resistor?

Question 15: On a 4-wire, 3-phase wye feeder, when must the neutral be counted as a current-carrying conductor for ampacity adjustment?

Question 16: Type NM-B cable has 90 °C rated conductors. What temperature rating sets the final ampacity of NM cable?

Question 17: A cable is installed under metal-corrugated sheet roof decking. What is the minimum distance from the nearest surface of the roof decking to the cable?

Question 18: Unless specifically permitted elsewhere in the Code, the maximum overcurrent protection for 14 AWG copper conductors is:

Question 19: A field-installed 10 ft feeder tap leaves the enclosure in which the tap is made. The feeder is protected at 600 A. What minimum ampacity must the tap conductors have, apart from the load they supply?

Question 20: A feeder supplies three 460-volt, 3-phase motors: 30 hp (40 A), 15 hp (21 A) and 10 hp (14 A). The 30 hp motor branch circuit is protected by a 100 A inverse time breaker. What is the maximum standard rating of the feeder breaker?

Question 21: What is the minimum ampere rating of the disconnecting means for a 20 hp, 460-volt, 3-phase motor?

Question 22: Each commercial occupancy accessible to pedestrians must have at least one sign outlet supplied by a branch circuit rated at least:

Question 23: During motor starting, the voltage at the fire pump controller line terminals must not drop more than what percentage below normal?

Question 24: In a major repair garage without the ventilation specified in Article 511, the area from the floor up to what height is classified as Class I, Division 2?

Question 25: At a marina, receptacles that provide shore power for boats must have individual ground-fault protection of equipment set to open at not more than:

Question 26: A permanently connected 4.5 kW water heater is supplied from a panelboard in another room. When may its branch-circuit breaker serve as the disconnecting means?

Question 27: In a bathroom, a switch controls the lighting load. Which conductor must generally be provided at the switch location?

Question 28: Straight runs of 1 in. rigid metal conduit made up with threaded couplings may be supported at intervals not exceeding what distance (where supports prevent transmission of stresses to terminations)?

Question 29: A box containing a receptacle is supported only by the conduits entering it. What is required?

Question 30: The ampacity of the conductors from the output terminals of a generator to the first distribution device containing overcurrent protection must be at least what percentage of the generator nameplate current rating?

Key NEC References for This Test

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