Journeyman Electrician Practice Test 30

Question 1: Lampholders connected to a branch circuit rated over 20 A must be of what type?

• Heavy-duty type
• Any medium-base type
• Keyless porcelain only
• Weatherproof type only

NEC Reference: NEC 210.21(A)

Question 2: At least how much of a rod or pipe electrode must be in contact with the soil?

• 6 ft
• 8 ft
• 9 ft
• 10 ft

NEC Reference: NEC 250.53(A)(4)

Question 3: Where is Type AC cable permitted to be installed?

• Exposed and concealed work
• In damp and wet locations
• Only in exposed work
• Only in concealed work

NEC Reference: NEC 320.10

Question 4: A marina feeder supplies 6 shore-power receptacles. What demand factor applies under Table 555.6?

• 70%
• 80%
• 90%
• 100%

NEC Reference: NEC 555.6 and Table 555.6

Question 5: Copper bars in a sheet metal auxiliary gutter may carry continuous current of not more than how many amperes per square inch of cross section?

• 700 A
• 750 A
• 900 A
• 1,000 A

NEC Reference: NEC 366.23(A)

Question 6: Kirchhoff's voltage law states that, around any closed loop of a circuit:

• Resistance equals voltage times current
• Power equals current squared
• The currents entering a junction equal the currents leaving it
• The sum of the voltage drops equals the source voltage

Question 7: A combination surface metal raceway carries both power circuits and signaling (data) circuits. What is required?

• Separate, identified compartments
• Only power circuits may use surface raceway
• A separate raceway for every circuit
• Nothing; they may share one channel

NEC Reference: NEC 386.70

Question 8: In a series circuit, how does the current through each element compare?

• It is largest through the largest resistor
• It is zero in the last element
• It divides among the elements
• It is the same through every element

Question 9: How is the direction of rotation of a DC shunt motor reversed?

• Reduce the shunt field current
• Reverse the polarity of the supply
• Reverse armature or field, not both
• Reverse both armature and field leads

Question 10: What does a wattmeter connected to an AC circuit measure?

• Reactive power (VAR)
• Power factor only
• Apparent power (VA)
• True power (W)

Question 11: Per NEC 250.52(A)(5), what is the minimum diameter for an unlisted steel (or zinc-coated steel) ground rod electrode?

• 1/2 inch (listed rods only)
• 5/8 inch
• 3/4 inch
• 3/8 inch

NEC Reference: NEC 250.52(A)(5)

Question 12: Per NEC 366.22, the sum of the cross-sectional areas of all conductors in a sheet metal auxiliary gutter shall not exceed what percentage of the gutter's interior cross-sectional area?

• 20%
• 40%
• 50%
• 75%

NEC Reference: NEC 366.22

Question 13: In a DC motor, increasing the field current will .............

• Increase motor speed
• Decrease motor speed
• Have no effect on speed
• Reverse motor direction

Question 14: A branch circuit uses 10 AWG conductors but is protected by a 20 A breaker. What is the rating of the branch circuit?

• 30 A, the conductor ampacity
• 20 A, the overcurrent device rating
• 25 A, the average
• 35 A, the 75 °C ampacity

NEC Reference: NEC 210.3

Question 15: Surface metal raceways installed on a wall in a commercial office are .............

• Prohibited — surface metal raceway cannot be used in commercial buildings
• Permitted — dry commercial locations are an approved use
• Permitted only if concealed within the wall
• Prohibited above suspended ceilings

NEC Reference: NEC 386.10

Question 16: A conductor has a resistance of 4 ohms and dissipates 100 watts of heat. What current is flowing in the conductor?

• 25 amperes
• 5 amperes
• 10 amperes
• 4 amperes

Question 17: According to Ohm's Law, if the voltage in a circuit is doubled while resistance stays constant, the current will .............

• Be halved
• Double
• Remain the same
• Quadruple

Question 18: What is the SI unit of magnetic flux?

• Weber
• Farad
• Henry
• Tesla

Question 19: Type AC cable is installed in thermal insulation. What ampacity limit applies?

• The 90 °C ampacity may always be used
• The 75 °C ampacity applies
• 90 °C conductors, 60 °C ampacity
• AC cable may not be used in insulation

NEC Reference: NEC 320.80(A)

Question 20: Why is surface metal raceway (Wiremold) prohibited in elevator hoistways?

• Because SMR cannot be installed vertically
• Because moving elevator components could impact and damage the raceway
• Because hoistways have high humidity
• Because SMR is not rated for the voltage used in elevators

NEC Reference: NEC 386.12

Question 21: Rigid steel conduit is threaded in the field where corrosion protection is needed. What must be done to the field-cut threads?

• Nothing is required
• Coat them with conductive anti-corrosion compound
• Paint them with enamel
• Wrap them with PTFE thread tape

NEC Reference: NEC 300.6(A)

Question 22: Grounded conductors of a 208Y/120-volt system and a 480Y/277-volt system share an enclosure. How must they be identified?

• Both must be green
• Distinguishable by system, e.g. white and gray
• Both may simply be white
• They may never share an enclosure

NEC Reference: NEC 200.6(D)

Question 23: A main bonding jumper in a panelboard consists only of a screw. How must the screw be identified?

• A red tag
• A white finish
• It needs no identification
• Green finish, visible when installed

NEC Reference: NEC 250.28(B)

Question 24: In a kitchen, countertop space wider than 12 inches that is separated from other countertop areas by a range, refrigerator, or sink must have .............

• No receptacle required if it connects to another counter space
• At least one receptacle outlet
• Two receptacle outlets minimum
• A dedicated 20A circuit for that section only

NEC Reference: NEC 210.52(C)(1)

Question 25: May a listed manual motor controller serve as the motor disconnecting means?

• Yes, if marked Suitable as Motor Disconnect
• Only for motors under 1 hp
• Never; a separate disconnect is required
• Yes, any manual starter may be used

NEC Reference: NEC 430.109(A)(6)

Question 26: A motor controller must have a voltage rating .............

• Always greater than 600V regardless of circuit
• Not less than the voltage of the circuit
• Equal to exactly 120V or 240V only
• Determined only by the horsepower rating

NEC Reference: NEC 430.83

Question 27: Two batteries of 12V and 6V are connected in series aiding (positive terminal of one to negative terminal of the other). What is the total voltage?

• 6 volts
• 18 volts
• 12 volts
• 72 volts

Question 28: A 20-ampere, AC-only general-use snap switch controls a motor. What is the maximum motor full-load current it may control?

• 10 A
• 16 A
• 20 A
• 25 A

NEC Reference: NEC 404.14(A)

Question 29: AFCI protection in a dwelling unit living room is required for branch circuits supplying .............

• Only receptacle outlets (not lighting)
• All outlets and devices including lighting outlets
• Only 20A circuits — 15A circuits are exempt
• Only circuits with extension cords

NEC Reference: NEC 210.12(A)

Question 30: A ground-fault protection of equipment (GFPE) system is installed on a 1,200 A service. What does 230.95(C) require when it is first installed?

• Testing only by the serving utility
• Annual testing by the owner only
• An on-site test with a written record
• Nothing; it is factory tested

NEC Reference: NEC 230.95(C)