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Journeyman Electrician Exam (NEC) practice questions

215 free questions with answers and explanations.

Practice test
  1. 101.A residential garage requires a new 120-volt, 20-ampere branch circuit for general-purpose receptacles. According to the NEC, how many such circuits are minimally required for a one-car attached garage of a dwelling unit?Equipment and Devices
  2. 102.A journeyman electrician is installing control wiring for a motor control center. The control circuit conductors are protected by a 10-ampere overcurrent device. What is the minimum size copper control circuit conductor permitted for a Class 1 control circuit, assuming they do not extend beyond the control enclosure?Equipment and Devices
  3. 103.A technician is installing a new 120-volt, 60-watt incandescent luminaire in a dwelling unit. What is the minimum length of free conductor that must be left at each outlet, junction, and switch point for splices or the connection of luminaires or devices?Equipment and Devices
  4. 104.A journeyman electrician is installing a 277-volt LED luminaire in a commercial warehouse. What is the maximum continuous load permitted on a 20-ampere branch circuit supplying this luminaire?Equipment and Devices
  5. 105.A technician is installing a new service disconnect for a commercial building. According to NEC 230.70(A)(1), what is the maximum height above the finished grade or working platform that the operating handle of the service disconnecting means can be located?Equipment and Devices
  6. 106.A journeyman electrician is installing a new 480-volt, 3-phase, 20-horsepower motor. What is the maximum rating of the inverse time circuit breaker that can be used for branch-circuit short-circuit and ground-fault protection if the motor's full-load current (FLA) is 27 amperes?Equipment and Devices
  7. 107.A client requests a new 120-volt, 15-ampere duplex receptacle to be installed in a basement for general use. Which type of overcurrent protection must this receptacle circuit incorporate according to the NEC?Equipment and Devices
  8. 108.A new 480-volt, 75 kVA, 3-phase transformer is being installed to supply a 208Y/120-volt panelboard. The primary overcurrent protection is provided by fuses. What is the maximum rating of the primary fuses permitted if the transformer's full-load primary current is 90.2 amperes?Equipment and Devices
  9. 109.A technician is installing a new 120-volt, 15-ampere general-purpose duplex receptacle in a dry location. Which NEMA configuration is typically used for this application?Equipment and Devices
  10. 110.A pilot device, such as a push button or limit switch, is used in a motor control circuit. What is the primary function of a pilot device in this context?Equipment and Devices
  11. 111.A journeyman electrician is installing a 3-phase, 480-volt, 30-horsepower squirrel-cage induction motor. According to NEC Table 430.250, what is the motor's full-load current (FLA) for the purpose of sizing overcurrent protection and conductors?Equipment and Devices
  12. 112.A journeyman electrician is calculating the minimum required feeder size for a commercial kitchen with multiple 120-volt, 20-ampere general-purpose receptacle branch circuits. According to the National Electrical Code, what is the demand factor that can be applied to the portion of the receptacle load exceeding 10 kVA for a non-dwelling unit?Equipment and Devices
  13. 113.A technician is installing a single-phase, 120-volt, 15-ampere hermetic refrigerant motor-compressor. What is the maximum rating of the branch-circuit overcurrent protective device (OCPD) permitted if the motor-compressor's rated-load current (RLC) is 12 amperes?Equipment and Devices
  14. 114.A commercial occupancy requires a feeder to supply a continuous load of 75 amperes and a non-continuous load of 50 amperes. The conductors are 75°C rated. What is the minimum required ampacity for the ungrounded feeder conductors?Services, Feeders, and Branch Circuits
  15. 115.A kitchen in a dwelling unit contains a permanently installed dishwasher, a trash compactor, and a microwave oven. How many 20-ampere small-appliance branch circuits are required, at minimum, to serve the receptacle outlets for these appliances, according to NEC 210.52(B)?Services, Feeders, and Branch Circuits
  16. 116.A dwelling unit has a 240-volt, single-phase electric clothes dryer with a nameplate rating of 5.5 kW. What is the minimum demand load for this dryer, according to NEC Table 220.54?Services, Feeders, and Branch Circuits
  17. 117.An industrial facility has a switchboard supplied by a 480V, 3-phase, 3-wire system. Per NEC 110.26(E), what is the minimum headroom required above this switchboard?Services, Feeders, and Branch Circuits
  18. 118.A technician is installing a 200-ampere, 120/240V, single-phase service for a new dwelling unit. What is the minimum size grounding electrode conductor (GEC) required if it connects to a ground rod?Services, Feeders, and Branch Circuits
  19. 119.A commercial building has a 200-ampere, 120/208V, 3-phase, 4-wire service. The feeder supplying a panelboard has a calculated non-continuous load of 80 amperes and a continuous load of 100 amperes. What is the minimum ampere rating for the overcurrent protective device (OCPD) for this feeder?Services, Feeders, and Branch Circuits
  20. 120.A panelboard in a commercial occupancy contains overcurrent devices, with the highest continuous load on any given circuit being 30 amperes. What is the maximum percentage of the total overcurrent device ampere rating that the continuous load is permitted to exceed, according to NEC 215.2(A)(1) and 230.42(A)(1) for feeders and services?Services, Feeders, and Branch Circuits
  21. 121.A service entrance conductor for a single-family dwelling is installed underground. The service is 200 amperes, 240V. What is the minimum depth of cover required for PVC conduit enclosing these conductors, where the voltage does not exceed 1000V, and no special conditions apply, according to NEC Table 300.5?Services, Feeders, and Branch Circuits
  22. 122.A residential dwelling unit has a total calculated load of 12,500 VA. What is the minimum standard ampere rating for the main overcurrent device, according to NEC 240.6(A)?Services, Feeders, and Branch Circuits
  23. 123.A client requests the installation of a 120-volt, 20-ampere branch circuit for lighting in a dwelling unit. The circuit conductors are run in EMT conduit. What is the minimum size copper equipment grounding conductor (EGC) required for this circuit, according to NEC 250.122?Services, Feeders, and Branch Circuits
  24. 124.A commercial building has a 400-ampere, 208Y/120V, 3-phase, 4-wire service. The main service disconnecting means consists of six circuit breakers in a single enclosure. What is the maximum number of disconnecting means permitted for a single service?Services, Feeders, and Branch Circuits
  25. 125.A commercial building requires a new 277-volt lighting circuit. The branch circuit will consist of three 10 AWG THHN conductors and one 10 AWG bare copper grounding conductor, run in a 3/4-inch Rigid Metal Conduit (RMC) for 75 feet. What is the minimum size square junction box required for a straight pull through these four conductors without splices?Wiring Methods and Materials
  26. 126.A journeyman electrician is installing a new 240-volt, 30-amp circuit for a water heater in a dwelling unit. The circuit will be run through a 1/2-inch EMT conduit. What is the maximum number of 10 AWG THHN copper conductors permitted in this conduit?Wiring Methods and Materials
  27. 127.A technician is connecting a new light fixture to an existing junction box. The light fixture has an integral junction box. According to NEC 314.16(A), when calculating the minimum box volume, how many conductor equivalents must be counted for a luminaire (lighting fixture) that has an integral junction box, and has no splices or connections other than to the conductors supplying the luminaire?Wiring Methods and Materials
  28. 128.An electrician is installing a new 20-amp, 120-volt circuit for a dedicated refrigerator outlet. The circuit consists of 12 AWG THHN conductors run in a 1/2-inch EMT conduit. The conduit passes through a fire-rated wall. What is the NEC requirement for sealing the penetration of the conduit through the fire-rated wall?Wiring Methods and Materials
  29. 129.A commercial electrician is installing a new circuit in a Class I, Division 1 hazardous location. Which of the following wiring methods is NOT permitted for use in this type of hazardous location?Wiring Methods and Materials
  30. 130.A maintenance technician is replacing a damaged flexible cord on a portable 277-volt industrial lighting fixture. The cord has three conductors and a bare equipment grounding conductor. Which of the following color combinations is permitted for the insulated circuit conductors?Wiring Methods and Materials
  31. 131.A client requests a new 120/240-volt, 100-amp single-phase service entrance for a small workshop. The service conductors will be installed in a wet location. What is the minimum size XHHW-2 aluminum service-entrance conductor required for this service?Wiring Methods and Materials
  32. 132.A journeyman is installing a new 240-volt, 50-amp circuit for an electric range in a dwelling unit using nonmetallic-sheathed cable (NM-B). The cable contains three 6 AWG copper conductors and one 10 AWG bare copper grounding conductor. What is the minimum size of the equipment grounding conductor required by the NEC for this circuit?Wiring Methods and Materials
  33. 133.A journeyman electrician is installing a temporary power pole for a construction site. The overhead conductors from the utility drop will be attached to the pole. What is the minimum clearance required for these service drop conductors above a public street, alley, or public road, that is subject to truck traffic?Wiring Methods and Materials
  34. 134.A licensed electrician is installing a 200-amp service entrance for a new single-family dwelling. The service conductors will be run through a 2-inch Rigid Metal Conduit (RMC) from the meter base to the service disconnecting means. According to NEC Article 230.6, what is the maximum length of RMC allowed to enclose service entrance conductors INSIDE the building before reaching the service disconnecting means?Wiring Methods and Materials
  35. 135.A technician is installing a new 200-amp, 240-volt single-phase feeder to a detached garage. The feeder conductors are 3/0 AWG THWN copper. What is the minimum size copper equipment grounding conductor (EGC) required for this feeder?Wiring Methods and Materials
  36. 136.A residential electrician is installing a new 120-volt, 20-amp branch circuit for kitchen counter receptacles. The circuit will be run through a 1/2-inch EMT conduit. According to NEC Table 310.16, if using THHN insulated conductors, what is the maximum number of 12 AWG conductors permitted in this conduit, assuming no derating for ambient temperature or number of current-carrying conductors is required?Wiring Methods and Materials
  37. 137.A technician is installing a new 480-volt, 3-phase motor circuit using 3 AWG copper conductors with THHN insulation. The conductors will be run in an ambient temperature of 45°C (113°F). What is the maximum allowable ampacity for these conductors, assuming no more than three current-carrying conductors in the raceway?Wiring Methods and Materials
  38. 138.A maintenance technician is replacing a flexible cord on a portable industrial machine operating at 480 volts. The original cord had a green insulated conductor. What is the NEC-mandated color for the equipment grounding conductor in a flexible cord?Wiring Methods and Materials
  39. 139.A journeyman electrician is installing a new 480-volt, 3-phase motor circuit using 1 AWG THHN copper conductors in a 1-inch Rigid Metal Conduit (RMC). What is the minimum length of free conductor that must be left at each outlet, junction, and switch point for making splices or terminations?Wiring Methods and Materials
  40. 140.A commercial building requires a new 20-amp, 120-volt branch circuit for general-purpose receptacles. The circuit will use 12 AWG THHN copper conductors in Electrical Metallic Tubing (EMT). What is the maximum number of current-carrying conductors permitted in the conduit before ampacity derating is required?Wiring Methods and Materials
  41. 141.A commercial electrician is installing a new 20-amp, 120-volt branch circuit in a suspended ceiling using Type MC cable. The cable is supported by straps and is not passing through any fire-rated assemblies. What is the maximum distance between points of support for this Type MC cable?Wiring Methods and Materials
  42. 142.A residential electrician is installing a new 20-amp, 120-volt branch circuit in a dwelling unit using nonmetallic-sheathed (NM) cable. The cable passes through a bored hole in a wood joist. The nearest edge of the bored hole must be no less than what distance from the nearest edge of the joist?Wiring Methods and Materials
  43. 143.A technician is installing a new 20-amp, 120-volt branch circuit in a commercial office. The circuit uses 12 AWG THHN conductors in EMT. The conductors are connected to a terminal block where the circuit conductor enters the terminal directly, without a splice. This type of connection is known as a:Wiring Methods and Materials
  44. 144.A client requests a new 240-volt, 30-amp circuit for an electric vehicle charging station in their attached garage. The circuit will originate from the main service panel. Which type of cable is generally NOT permitted for this application within the wall cavities of a residential building, according to the NEC?Wiring Methods and Materials
  45. 145.An industrial electrician is running a new 480-volt feeder through an area where corrosive fumes are regularly present. Which type of raceway is generally considered the most suitable for this environment, according to the NEC?Wiring Methods and Materials
  46. 146.A residential electrician is installing a new ceiling fan with a support box. The fan weighs 45 pounds. What is the minimum weight rating required for the outlet box supporting this ceiling fan?Wiring Methods and Materials
  47. 147.A commercial building requires a new 208-volt, 3-phase, 60-amp feeder circuit to a subpanel using individual 6 AWG THHN copper conductors in a flexible metal conduit (FMC). The FMC will be used as the equipment grounding conductor. What is the maximum length of FMC permitted to serve as the equipment grounding conductor for this circuit, according to NEC 250.118(5)?Wiring Methods and Materials
  48. 148.A commercial electrician is installing a new 480-volt, 3-phase motor feeder in a wet location. The feeder consists of three 3/0 AWG THW copper conductors and one 6 AWG copper equipment grounding conductor. What is the minimum radius for a conduit bend if using 2-inch Rigid Metal Conduit (RMC)?Wiring Methods and Materials
  49. 149.An electrical contractor is installing a series of nonmetallic boxes for a residential lighting circuit. According to NEC 314.17(C), what is the maximum length of conductor that must be left free at each box opening to allow for splices or the connection of luminaires or devices?Wiring Methods and Materials
  50. 150.An industrial electrician is installing a new control circuit in a hazardous location identified as Class I, Division 2. Which of the following wiring methods is generally NOT permitted for the interconnection of devices in this specific location?Wiring Methods and Materials