Journeyman Electrician Practice Test 20

Question 1: To qualify as a grounding electrode, a metal underground water pipe must be in direct contact with the earth for at least:

• 5 ft
• 10 ft
• 20 ft
• 30 ft

NEC Reference: NEC 250.52(A)(1)

Question 2: Bonding jumpers from several grounding electrodes are connected to a copper busbar instead of running one unbroken GEC. What is the minimum size of the busbar?

• ⅛ in. × 1 in.
• ¼ in. × 1 in.
• ¼ in. × 2 in.
• ½ in. × 4 in.

NEC Reference: NEC 250.64(F)(3)

Question 3: How may the equipment grounding conductor be connected to a metal outlet box?

• Tucked behind the device yoke when mounted
• With any sheet-metal screw into the box
• Wrapped around the cable clamp screw
• A dedicated grounding screw or listed device

NEC Reference: NEC 250.148(C)

Question 4: A separately derived system (transformer) is located outdoors, away from the building it supplies. What grounding is required at the transformer?

• A connection to the utility pole ground only
• Only an EGC run back to the service
• None; grounding is done only at the building
• An electrode connection at the source

NEC Reference: NEC 250.30(C)

Question 5: A rebar stub is extended from a concrete-encased electrode up through the foundation to connect the GEC. Which condition applies?

• No earth contact without corrosion protection
• It may touch the earth without any protection
• It must be at least No. 6 (¾ in.) rebar
• It may interconnect separate electrode systems

NEC Reference: NEC 250.68(C)(3)

Question 6: How much current does a 1,500-watt, 120-volt space heater draw?

• 8 A
• 12.5 A
• 15 A
• 18 A

Question 7: A 5 kW heater runs for 8 hours. Electricity costs $0.15 per kWh. What is the cost of operation?

• $60.00
• $12.00
• $6.00
• $0.60

Question 8: An existing building has one year of demand data showing a maximum demand of 120 kW. A 30 kW load is being added. Using 220.87, what total load must the existing service carry?

• 150 kW
• 157.5 kW
• 180 kW
• 187.5 kW

NEC Reference: NEC 220.87

Question 9: A dwelling unit kitchen requires at least how many 20-ampere small-appliance branch circuits?

• 1
• 2
• 3
• 4

NEC Reference: NEC 210.11(C)(1)

Question 10: In a dwelling living room, receptacles must be placed so that no point along the floor line of any wall space is more than how far from a receptacle?

• 4 ft
• 6 ft
• 8 ft
• 12 ft

NEC Reference: NEC 210.52(A)(1)

Question 11: Overhead service conductors run horizontally just above the top of a window that can be opened. What clearance from the window is required?

• 8 ft measured from the edge of the window frame
• 3 ft in every direction from the window
• 10 ft measured above the top of the window
• None; runs above the window top are exempt

NEC Reference: NEC 230.9(A)

Question 12: Under 110.2, conductors and equipment required or permitted by the NEC must be:

• Approved (acceptable to the AHJ)
• Installed by a licensed master electrician
• Rated for at least 600 volts
• Manufactured in the United States

NEC Reference: NEC 110.2

Question 13: A splice is to be soldered. What must be done before the solder is applied?

• Wrap the conductors tightly with friction tape
• Coat the conductors with antioxidant compound
• Nothing; the solder alone holds the splice
• Join them mechanically and electrically first

NEC Reference: NEC 110.14(B)

Question 14: Under the 2023 NEC, in other than dwelling units, a permanent arc-flash label showing nominal voltage, available fault current, clearing time and date is required on service and feeder-supplied equipment rated:

• 400 A or more
• 800 A or more
• 1,000 A or more
• 1,200 A or more

NEC Reference: NEC 110.16(B)

Question 15: When Type NM cable is bent, the radius of the inner edge of the bend must be at least how many times the cable diameter?

• 3
• 5
• 8
• 10

NEC Reference: NEC 334.24

Question 16: Type NM cable is subject to physical damage. Which of these may protect it?

• EMT or Schedule 80 PVC conduit
• Duct tape wrapped around it
• Flexible nonmetallic tubing
• Schedule 40 PVC conduit

NEC Reference: NEC 334.15(B)

Question 17: A raceway contains two 120/240-volt, single-phase, 3-wire multiwire branch circuits (each with two ungrounded conductors and a shared neutral) and one EGC. How many current-carrying conductors are counted for ampacity adjustment?

• 4
• 5
• 6
• 7

NEC Reference: NEC 310.15(E)(1) and 310.15(F)

Question 18: A circuit breaker serving as an overcurrent device must be installed so the center of the grip of its handle, in its highest position, is not more than how high above the floor or working platform?

• 8 ft 0 in.
• 7 ft 0 in.
• 6 ft 7 in.
• 6 ft 0 in.

NEC Reference: NEC 240.24(A)

Question 19: Transformer secondary conductors are installed outdoors from the transformer to a building. Under 240.21(C)(4), what is their maximum length?

• 100 ft in total length
• 10 ft, the same as a feeder tap
• 25 ft, the same as an indoor tap
• No length limit applies

NEC Reference: NEC 240.21(C)(4)

Question 20: Must a motor controller open all conductors to the motor?

• No, unless it is also the disconnect
• Only on 3-phase motors over 50 hp
• Only for motors larger than 2 hp
• Yes, it must always open every conductor

NEC Reference: NEC 430.84

Question 21: A 50 hp, 460-volt, 3-phase motor uses a wye-start, delta-run controller. What minimum ampacity is required for the conductors between the controller and the motor?

• 37.7 A
• 47.1 A
• 65.0 A
• 81.3 A

NEC Reference: NEC 430.22(C) and Table 430.250

Question 22: An outdoor standby generator has a readily accessible disconnect located within sight of the building it supplies. Is another disconnect required where the conductors enter the building?

• Only for 3-phase standby generators
• Only if the conductors exceed 25 ft
• Yes, a second disconnect is always required
• No; the generator disconnect is enough

NEC Reference: NEC 702.12(A)

Question 23: A PV system disconnect may have its line and load terminals energized when open. What must it be marked with?

• A warning that both sides may be energized
• The date the PV system was installed
• The serial number of the inverter panel
• Only the manufacturer's name and model

NEC Reference: NEC 690.13(B)

Question 24: How must each general care (Category 2) patient bed location be supplied?

• Two circuits: critical branch plus normal
• By an isolated power system only
• By one normal-system branch circuit
• By two normal branch circuits from one panel

NEC Reference: NEC 517.18(A)

Question 25: Temporary flexible cords and cables on a construction site must be protected from:

• Nothing; temporary wiring is exempt from it
• Sunlight only, using UV-rated jackets
• Rain only, using weatherproof covers
• Accidental damage at corners and pinch points

NEC Reference: NEC 590.4(H)

Question 26: How must a single-throw knife switch be connected?

• With the supply on the hinge side, energizing the blades
• In either direction
• So the blades are energized when open
• So the blades are de-energized when the switch is open

NEC Reference: NEC 404.6(C)

Question 27: A built-in dishwasher is cord-and-plug connected. What cord length is permitted, measured from the face of the plug to the plane of the rear of the appliance?

• 4 ft to 8 ft
• 2 ft to 4 ft
• 3 ft to 6.5 ft
• 1 ft to 3 ft

NEC Reference: NEC 422.16(B)(2)

Question 28: A box has two internal cable clamps. How are the clamps counted for box fill?

• One volume, based on the largest conductor
• Two volumes, one for each clamp
• They are not counted at all
• A double volume for each clamp

NEC Reference: NEC 314.16(B)(2)

Question 29: A single 3-conductor cable is installed alone in a conduit. What maximum percentage of the conduit area may it occupy?

• 31%
• 40%
• 53%
• 60%

NEC Reference: NEC Chapter 9, Table 1 and Note 9

Question 30: A single-phase transformer supplies a 240-volt load that draws 62.5 A at full rating. What is the transformer kVA rating?

• 7.5 kVA
• 15 kVA
• 25 kVA
• 26 kVA