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NH Journeyman Electrician practice questions

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Question 1National Electrical Code (NFPA 70) and code changes

Under NEC Article 100, what does the term "ampacity" mean for a conductor?

  1. The maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating Correct answer.
  2. The ampacity value printed on the overcurrent device protecting the circuit
  3. The current at which a conductor's insulation begins to char during a short circuit
  4. The average current a conductor carries over a 24-hour operating period

Explanation

Article 100 defines ampacity as the maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. The phrase "conditions of use" is why Table 310.16 values must be adjusted for ambient temperature and conductor count.

Question 2National Electrical Code (NFPA 70) and code changes

A dwelling unit has a 120/240-volt single-phase service. Which NEC section establishes the minimum number of 20-ampere small-appliance branch circuits required in the kitchen and dining areas?

  1. Section 422.10
  2. Section 220.52(A)
  3. Section 406.4
  4. Section 210.11(C)(1) Correct answer.

Explanation

Section 210.11(C)(1) requires at least two 20-ampere small-appliance branch circuits for receptacle outlets in the kitchen, pantry, dining room, and similar areas. Section 220.52(A) only tells you how to calculate the load on those circuits.

Question 3National Electrical Code (NFPA 70) and code changes

A 60-ampere, 240-volt branch circuit supplies a fixed appliance. What is the minimum copper conductor size permitted, assuming 60°C terminals and no adjustment or correction factors?

  1. 8 AWG
  2. 4 AWG
  3. 6 AWG Correct answer.
  4. 10 AWG

Explanation

Using the 60°C column of Table 310.16, 6 AWG copper has an ampacity of 55 amperes, which is not enough for 60 amperes; however, 6 AWG is the smallest size that satisfies the 60-ampere circuit when the 75°C column (65 amperes) applies to conductors used with 60-ampere equipment rated 100 amperes or less. The practical minimum for a 60-ampere circuit is therefore 6 AWG copper.

Question 4National Electrical Code (NFPA 70) and code changes

What is the maximum standard overcurrent device rating permitted to protect a 10 AWG copper branch-circuit conductor with 60°C insulation, where the ampacity is 30 amperes?

  1. 35 amperes
  2. 30 amperes Correct answer.
  3. 25 amperes
  4. 40 amperes

Explanation

Section 240.4 generally requires the overcurrent device to be rated not more than the conductor ampacity. For 10 AWG copper at 30 amperes, the maximum standard rating is 30 amperes unless a specific exception such as 240.4(D) or (E) applies.

Question 5National Electrical Code (NFPA 70) and code changes

Which NEC article contains the requirements for grounding and bonding, including the grounding electrode system and equipment grounding conductors?

  1. Article 250 Correct answer.
  2. Article 310
  3. Article 300
  4. Article 200

Explanation

Article 250 covers grounding and bonding requirements, including the grounding electrode system, equipment grounding conductors, and bonding jumpers. Article 200 covers identification of grounded conductors, and Articles 300 and 310 address wiring methods and conductors.

Question 6National Electrical Code (NFPA 70) and code changes

A 200-ampere service uses a 2/0 AWG copper conductor for the ungrounded service conductors. What is the minimum size copper grounding electrode conductor required where the service is 120/240-volt single-phase and the grounding electrode is a metal water pipe?

  1. 1/0 AWG
  2. 4 AWG Correct answer.
  3. 6 AWG
  4. 2 AWG

Explanation

Table 250.66 sizes the grounding electrode conductor based on the largest ungrounded service conductor. For 2/0 AWG copper, the table requires 4 AWG copper. The conductor is not required to be larger than 6 AWG for a rod, pipe, or plate electrode, but a water pipe is a different electrode type.

Question 7National Electrical Code (NFPA 70) and code changes

In a 120/240-volt single-phase panelboard, which conductor color is permitted for the grounded conductor?

  1. Orange
  2. White or gray Correct answer.
  3. Green
  4. Bare copper

Explanation

Section 200.6 requires the grounded conductor to be identified by a continuous white or gray outer finish, or by three continuous white stripes on other than green insulation. Green is reserved for equipment grounding conductors.

Question 8National Electrical Code (NFPA 70) and code changes

What is the minimum working clearance in front of a 480-volt panelboard with exposed live parts on one side and no live parts or grounded surfaces on the other side, where the depth of the panel is 6 inches?

  1. 5 feet
  2. 4 feet
  3. 3 feet Correct answer.
  4. 3.5 feet

Explanation

Table 110.26(A)(1) sets the minimum clear distance for 151-600 volt equipment at 3 feet where there are exposed live parts on one side and no live or grounded parts on the other. The depth of the panel does not reduce the required clear distance.

Question 9National Electrical Code (NFPA 70) and code changes

A 20-ampere branch circuit supplies a receptacle in a commercial garage. What ground-fault circuit interrupter protection is required by Section 210.8(B)?

  1. GFCI protection is required for all 125-volt, single-phase, 15- and 20-ampere receptacles in the garage Correct answer.
  2. GFCI protection is required only for receptacles within 6 feet of a sink
  3. GFCI protection is required only for 30-ampere receptacles
  4. GFCI protection is not required in commercial garages

Explanation

Section 210.8(B) requires GFCI protection for 125-volt, single-phase, 15- and 20-ampere receptacles in garages and similar areas, including commercial garages, with limited exceptions. The requirement is not limited to receptacles near sinks.

Question 10National Electrical Code (NFPA 70) and code changes

Which wiring method is permitted for the exposed interior wiring of a commercial building where subject to physical damage?

  1. Surface metal raceway
  2. Electrical nonmetallic tubing
  3. Rigid metal conduit Correct answer.
  4. Nonmetallic sheathed cable

Explanation

Rigid metal conduit is permitted in exposed and subject-to-physical-damage locations, while nonmetallic sheathed cable and electrical nonmetallic tubing are generally restricted in such locations. Surface metal raceway is permitted in some exposed locations but has limitations that make rigid metal conduit the clearest correct choice for physical damage.

Question 11National Electrical Code (NFPA 70) and code changes

What is the maximum overcurrent protection permitted for a 240-volt, single-phase, 5-horsepower motor branch circuit using a standard inverse-time circuit breaker, where Table 430.52 lists 250 percent?

  1. 400 percent of the full-load current
  2. 300 percent of the full-load current
  3. 250 percent of the full-load current Correct answer.
  4. 175 percent of the full-load current

Explanation

Table 430.52 permits an inverse-time circuit breaker sized up to 250 percent of the motor full-load current for a standard motor. If the calculated value does not correspond to a standard rating, Section 430.52(C)(1) Exception No. 2 permits the next higher standard rating.

Question 12National Electrical Code (NFPA 70) and code changes

A 3-phase, 4-wire, 120/208-volt panelboard supplies a continuous load of 40 amperes. What is the minimum branch-circuit conductor ampacity required, before any adjustment or correction factors?

  1. 60 amperes
  2. 50 amperes Correct answer.
  3. 40 amperes
  4. 48 amperes

Explanation

Section 210.19(A)(1) requires branch-circuit conductors to have an ampacity of not less than 125 percent of the continuous load plus 100 percent of the noncontinuous load. 125 percent of 40 amperes is 50 amperes.

Question 13National Electrical Code (NFPA 70) and code changes

Which NEC article governs the installation of outlet boxes, junction boxes, and conduit bodies?

  1. Article 314 Correct answer.
  2. Article 340
  3. Article 330
  4. Article 320

Explanation

Article 314 covers outlet, device, pull, and junction boxes, conduit bodies, and fittings. Articles 320, 330, and 340 cover specific wiring methods such as armored cable, metal-clad cable, and underground feeder cable.

Question 14National Electrical Code (NFPA 70) and code changes

How many 12 AWG conductors are permitted in a 4-inch square, 1.5-inch deep metal box with a plaster ring marked for 2 cubic inches?

  1. Ten
  2. Eight
  3. Nine Correct answer.
  4. Seven

Explanation

A 4-inch square, 1.5-inch deep box has a volume of 21 cubic inches, and the plaster ring adds 2 cubic inches for 23 cubic inches total. Each 12 AWG conductor counts 2.25 cubic inches, so 23 divided by 2.25 is 10.2, but the box fill must also account for clamps, devices, and grounding conductors if present. With the ring and no other fill, the calculated conductor count is nine.

Question 15National Electrical Code (NFPA 70) and code changes

What is the minimum size copper equipment grounding conductor required for a 60-ampere branch circuit using 6 AWG copper conductors?

  1. 10 AWG Correct answer.
  2. 6 AWG
  3. 12 AWG
  4. 8 AWG

Explanation

Table 250.122 sizes equipment grounding conductors based on the rating of the overcurrent device. For a 60-ampere overcurrent device, 10 AWG copper is the minimum equipment grounding conductor, and it is not required to be larger than the circuit conductors.

Question 16National Electrical Code (NFPA 70) and code changes

A receptacle is installed in a wet location. Which of the following is required by Section 406.9?

  1. A cover that is weatherproof only when the plug is removed
  2. An unlisted receptacle with a gasket
  3. A weatherproof enclosure with a cover that remains weatherproof whether or not the attachment plug cap is inserted Correct answer.
  4. A standard metal cover plate

Explanation

Section 406.9(B) requires receptacles in wet locations to be installed in an enclosure that is weatherproof whether or not the attachment plug cap is inserted. A cover that is weatherproof only when the receptacle is unused does not satisfy the requirement.

Question 17National Electrical Code (NFPA 70) and code changes

What is the maximum permitted voltage drop for a branch circuit plus feeder combined, according to the informational notes in NEC 210.19(A) and 215.2(A)?

  1. 2 percent
  2. 10 percent
  3. 5 percent Correct answer.
  4. 3 percent

Explanation

The informational notes recommend that the total voltage drop for feeders plus branch circuits not exceed 5 percent, with branch circuits and feeders each limited to 3 percent. These are recommendations, not mandatory rules.

Question 18National Electrical Code (NFPA 70) and code changes

Which of the following is a characteristic of a listed circuit breaker used as a switch for a 480-volt motor branch circuit?

  1. It may be used as a switch only if it is rated 100 amperes or less
  2. It may be used as a switch only if it is a molded-case type
  3. It may never be used as a switch
  4. It may be used as a switch if it is listed for that purpose and marked with the switching rating Correct answer.

Explanation

Section 404.14 permits circuit breakers to be used as switches where they are listed for the purpose and marked with the appropriate switching rating. The rating and listing determine whether the device is suitable, not the breaker type alone.

Question 19National Electrical Code (NFPA 70) and code changes

A 2-inch rigid metal conduit is installed outdoors in a location subject to direct sunlight. What is the minimum required support interval according to Section 344.30?

  1. 10 feet Correct answer.
  2. 6 feet
  3. 12 feet
  4. 5 feet

Explanation

Section 344.30 requires rigid metal conduit to be supported at intervals not exceeding 10 feet. Supports must also be within 3 feet of each box, cabinet, or fitting, and the conduit must be securely fastened.

Question 20National Electrical Code (NFPA 70) and code changes

What is the minimum size of a copper grounding electrode conductor for a 400-ampere service with 500 kcmil copper service conductors, where the grounding electrode is a concrete-encased electrode?

  1. 2 AWG
  2. 4 AWG
  3. 1/0 AWG Correct answer.
  4. 6 AWG

Explanation

Table 250.66 requires a 1/0 AWG copper grounding electrode conductor for 500 kcmil copper service conductors. For a concrete-encased electrode, Section 250.66(B) permits a 4 AWG copper conductor, but the question asks for the service grounding electrode conductor size based on the table.

Question 21National Electrical Code (NFPA 70) and code changes

Which NEC article covers the requirements for electric signs and outline lighting?

  1. Article 625
  2. Article 620
  3. Article 610
  4. Article 600 Correct answer.

Explanation

Article 600 covers electric signs and outline lighting, including their installation, disconnection means, and marking. Articles 610, 620, and 625 cover cranes and hoists, elevators, and electric vehicle charging systems.

Question 22National Electrical Code (NFPA 70) and code changes

A 120-volt, 15-ampere branch circuit supplies a bathroom receptacle in a dwelling unit. What protection is required by Section 210.8(A)(1)?

  1. GFCI protection Correct answer.
  2. Both GFCI and AFCI protection
  3. AFCI protection
  4. No special protection

Explanation

Section 210.8(A)(1) requires GFCI protection for all 125-volt, single-phase, 15- and 20-ampere receptacles in bathrooms of dwelling units. AFCI protection is required by 210.12 for branch circuits supplying outlets in dwelling unit rooms, but the bathroom receptacle requirement specifically calls for GFCI.

Question 23National Electrical Code (NFPA 70) and code changes

What is the maximum number of 8 AWG THHN copper conductors permitted in a 1-inch electrical metallic tubing with no fittings or boxes counted?

  1. Four
  2. Six Correct answer.
  3. Ten
  4. Eight

Explanation

Chapter 9, Table 1 limits the number of conductors in a raceway to 40 percent fill. A 1-inch EMT has a total area of 0.864 square inches, and 8 AWG THHN has an area of 0.0366 square inches, so 40 percent fill allows about nine conductors; however, the standard conduit fill table for 1-inch EMT lists six 8 AWG conductors for the common 40 percent fill value used in practice.

Question 24National Electrical Code (NFPA 70) and code changes

Which of the following is required for a 15-ampere, 125-volt receptacle installed in a dwelling unit kitchen countertop?

  1. It must be a 20-ampere receptacle
  2. It must be AFCI protected only
  3. It must be installed more than 6 feet from the sink
  4. It must be GFCI protected and be of the grounding type Correct answer.

Explanation

Section 210.8(A)(6) requires GFCI protection for kitchen countertop receptacles, and Section 406.4 requires receptacles to be of the grounding type where a grounding conductor is available. Kitchen countertop receptacles are also required to be supplied by the small-appliance branch circuits.

Question 25National Electrical Code (NFPA 70) and code changes

What is the minimum burial depth for rigid metal conduit installed under a driveway in a residential setting, per Table 300.5?

  1. 18 inches Correct answer.
  2. 12 inches
  3. 24 inches
  4. 6 inches

Explanation

Table 300.5 requires rigid metal conduit to be buried at least 18 inches beneath a residential driveway. The 24-inch depth applies to certain other conditions, such as under streets or where the conduit is not protected by a concrete slab.

Question 26National Electrical Code (NFPA 70) and code changes

Under NEC Section 90.4, who has the authority to grant a special permission for an installation that does not strictly comply with the Code?

  1. The listing agency that approved the equipment
  2. The authority having jurisdiction Correct answer.
  3. The manufacturer's field service representative
  4. The electrical contractor's licensed master electrician

Explanation

Section 90.4 assigns enforcement of the Code to the authority having jurisdiction, and that same body may grant special permission for installations that comply with the intent of the rules. The AHJ also interprets the Code and may waive specific requirements where equivalent safety is demonstrated. No other party holds this enforcement authority.

Question 27National Electrical Code (NFPA 70) and code changes

NEC Article 100 defines a "branch circuit" as the circuit conductors between the final overcurrent device protecting the circuit and which of the following?

  1. The panelboard busbar
  2. The outlet or outlets Correct answer.
  3. The service point
  4. The grounding electrode

Explanation

Article 100 defines the branch circuit as the conductors between the final overcurrent device and the outlet(s). The overcurrent device may be a breaker in a panelboard or a set of fuses, but the circuit ends at the outlets it serves. Anything upstream of that final overcurrent device is a feeder or service conductor.

Question 28National Electrical Code (NFPA 70) and code changes

Which NEC chapter contains the requirements for wiring methods and materials, including raceways, cables, and boxes?

  1. Chapter 3 Correct answer.
  2. Chapter 2
  3. Chapter 9
  4. Chapter 4

Explanation

Chapter 3, "Wiring Methods and Materials," covers Articles 300 through 398, including raceways, cable assemblies, boxes, and cabinets. Chapter 2 addresses general wiring and protection, Chapter 4 covers equipment for general use, and Chapter 9 contains tables. Knowing the chapter structure speeds navigation during the exam.

Question 29National Electrical Code (NFPA 70) and code changes

Section 110.14 requires that conductor splices and joints be made with which of the following?

  1. Twist-on connectors only
  2. Listed splicing devices or approved means Correct answer.
  3. Insulating tape only
  4. Solder alone

Explanation

Section 110.14 requires splices and joints to be made with listed splicing devices or by other approved means. The connection must also provide adequate electrical continuity and mechanical strength. Bare twisting or tape alone does not satisfy the requirement.

Question 30National Electrical Code (NFPA 70) and code changes

A conductor is marked "THHN/THWN-2." In a wet location, what is the significance of the "THWN-2" marking?

  1. It indicates the conductor is suitable only in dry locations
  2. It permits use in wet locations at up to 90 degrees C Correct answer.
  3. It indicates the conductor is a grounding conductor only
  4. It permits use in wet locations at up to 75 degrees C

Explanation

The "-2" suffix in THWN-2 denotes a 90 degrees C wet-location rating, per Table 310.104. A conductor marked only THWN would be limited to 75 degrees C in wet locations. The dual marking allows the higher ampacity column where the termination and conditions permit.

Question 31National Electrical Code (NFPA 70) and code changes

A 60-ampere branch circuit supplies a continuous load of 45 amperes. Using the standard 125 percent continuous-load factor, what is the minimum conductor ampacity required before any adjustment factors are applied?

  1. 56 amperes Correct answer.
  2. 45 amperes
  3. 75 amperes
  4. 60 amperes

Explanation

Section 210.19(A)(1) requires branch-circuit conductors to have an ampacity of at least 125 percent of the continuous load plus 100 percent of the noncontinuous load. Here, 45 amperes times 1.25 equals 56.25 amperes. The conductor selected must have an ampacity of at least 56.25 amperes before ampacity adjustments.

Question 32National Electrical Code (NFPA 70) and code changes

A feeder supplies a continuous load of 80 amperes and a noncontinuous load of 30 amperes. What is the minimum feeder overcurrent device rating using standard sizes, before any other considerations?

  1. 130 amperes
  2. 110 amperes
  3. 150 amperes
  4. 125 amperes Correct answer.

Explanation

Section 215.3 requires the feeder overcurrent device to be at least 125 percent of the continuous load plus 100 percent of the noncontinuous load. That equals 100 plus 30, or 130 amperes. Since 130 amperes is not a standard rating, the next higher standard size, 125 amperes, would not be permitted because it is below the calculated minimum; the next standard size at or above 130 is 150 amperes.

Question 33National Electrical Code (NFPA 70) and code changes

Which NEC article contains the requirements for grounding and bonding, including the grounding electrode system?

  1. Article 200
  2. Article 300
  3. Article 230
  4. Article 250 Correct answer.

Explanation

Article 250, "Grounding and Bonding," contains the rules for grounding electrode systems, equipment grounding conductors, bonding, and grounding electrode conductors. Article 230 covers services, Article 300 covers general wiring methods, and Article 200 covers the identification of the grounded conductor.

Question 34National Electrical Code (NFPA 70) and code changes

A dwelling unit has a 200-ampere service. What is the minimum size copper grounding electrode conductor required where the grounding electrode is a ground rod, per Table 250.66?

  1. 4 AWG
  2. 2 AWG
  3. 1/0 AWG
  4. 6 AWG Correct answer.

Explanation

Table 250.66 sizes the grounding electrode conductor by the largest ungrounded service conductor. For a 200-ampere service with 2/0 AWG copper service conductors, the table requires 6 AWG copper. The table is keyed to conductor size, not to the ampere rating alone.

Question 35National Electrical Code (NFPA 70) and code changes

Which of the following is required for a grounding electrode conductor installed in a metal raceway?

  1. The conductor must be larger than 6 AWG
  2. The conductor must be insulated throughout
  3. The conductor must be bonded to the raceway at each end Correct answer.
  4. The conductor must be installed in rigid metal conduit only

Explanation

Section 250.64(E) requires that a grounding electrode conductor installed in a ferrous metal raceway be bonded to the raceway at each end, and the raceway must be electrically continuous. This prevents inductive choking of the grounding path. Bonding is achieved with fittings listed for the purpose.

Question 36National Electrical Code (NFPA 70) and code changes

A 3-phase, 4-wire, 120/208-volt feeder supplies a 30-ampere continuous load and a 20-ampere noncontinuous load. What is the minimum feeder conductor ampacity before adjustment?

  1. 57.5 amperes Correct answer.
  2. 62.5 amperes
  3. 75 amperes
  4. 50 amperes

Explanation

Section 215.2(A)(1) requires feeder conductors to have an ampacity of at least 125 percent of the continuous load plus 100 percent of the noncontinuous load. That is 37.5 plus 20, or 57.5 amperes. The conductor must be selected so its ampacity is at least 57.5 amperes before any adjustment or correction factors.

Question 37National Electrical Code (NFPA 70) and code changes

Section 210.8(A) requires GFCI protection for receptacles in which dwelling-unit location?

  1. A bedroom
  2. A living room
  3. A hallway
  4. A kitchen countertop Correct answer.

Explanation

Section 210.8(A)(6) requires GFCI protection for all 125- through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts to ground or less in kitchens, including countertops. Bedrooms, living rooms, and hallways are not listed in 210.8(A) unless another condition applies.

Question 38National Electrical Code (NFPA 70) and code changes

A 120-volt, 20-ampere branch circuit supplies a receptacle in a dwelling-unit garage. What protection does Section 210.8(A) require?

  1. AFCI protection only
  2. Neither GFCI nor AFCI protection
  3. Ground-fault protection for equipment
  4. GFCI protection Correct answer.

Explanation

Section 210.8(A)(2) requires GFCI protection for all 125- through 250-volt receptacles in garages, accessory buildings, and boathouses. The requirement applies regardless of the branch-circuit rating within that voltage range. AFCI protection is a separate requirement and does not replace GFCI protection.

Question 39National Electrical Code (NFPA 70) and code changes

Which NEC article governs the installation of luminaires, lampholders, and lamps?

  1. Article 404
  2. Article 400
  3. Article 410 Correct answer.
  4. Article 422

Explanation

Article 410, "Luminaires, Lampholders, and Lamps," contains the installation requirements for lighting fixtures and related equipment. Article 400 covers flexible cords, Article 404 covers switches, and Article 422 covers appliances.

Question 40National Electrical Code (NFPA 70) and code changes

A luminaire is installed in a clothes closet. Which of the following is permitted by Section 410.16?

  1. A surface-mounted fluorescent fixture with a totally enclosed lamp Correct answer.
  2. A surface-mounted incandescent fixture with an exposed lamp
  3. A pendant-mounted fixture with an open lamp
  4. A recessed fixture with an open lamp

Explanation

Section 410.16 permits surface-mounted or recessed fluorescent or LED luminaires with totally enclosed lamps in clothes closets, provided they meet the clearance requirements. Incandescent fixtures with exposed lamps and pendant fixtures are prohibited because of the fire risk from stored clothing.

Question 41National Electrical Code (NFPA 70) and code changes

What is the minimum number of 20-ampere small-appliance branch circuits required for a dwelling-unit kitchen, per Section 210.11(C)(1)?

  1. Three
  2. Four
  3. One
  4. Two Correct answer.

Explanation

Section 210.11(C)(1) requires at least two 20-ampere small-appliance branch circuits for receptacle outlets in the kitchen, pantry, breakfast room, and dining room. These circuits may also supply other permitted outlets but must serve the small-appliance receptacles.

Question 42National Electrical Code (NFPA 70) and code changes

A 240-volt, single-phase, 10-horsepower motor is supplied by a branch circuit. Using Table 430.248 full-load current values, what is the minimum branch-circuit conductor ampacity before any adjustment factors?

  1. 50 amperes
  2. 55 amperes Correct answer.
  3. 60 amperes
  4. 70 amperes

Explanation

Table 430.248 lists a full-load current of 50 amperes for a 10-horsepower, 240-volt single-phase motor. Section 430.22 requires branch-circuit conductors to have an ampacity of at least 125 percent of the full-load current, which equals 62.5 amperes; however, the question asks for the minimum conductor ampacity before adjustment, which is 125 percent of 50 amperes, or 62.5 amperes. Among the choices, 70 amperes is the smallest value at or above 62.5.

Question 43National Electrical Code (NFPA 70) and code changes

What is the maximum overcurrent protection permitted for a 3-phase, 480-volt, 15-horsepower motor branch circuit using a nontime-delay fuse, per Table 430.52?

  1. 60 amperes
  2. 40 amperes Correct answer.
  3. 50 amperes
  4. 70 amperes

Explanation

Table 430.52 permits a nontime-delay fuse sized at 300 percent of the motor full-load current for a polyphase squirrel-cage motor. Table 430.250 lists 21 amperes for a 15-horsepower, 480-volt motor, and 300 percent of 21 equals 63 amperes; the next standard size is 70 amperes, but the question asks for the maximum permitted, which is the next standard size not exceeding the calculated value, 60 amperes.

Question 44National Electrical Code (NFPA 70) and code changes

Which NEC article covers the requirements for air-conditioning and refrigerating equipment, including hermetic refrigerant motor-compressors?

  1. Article 430
  2. Article 440 Correct answer.
  3. Article 445
  4. Article 450

Explanation

Article 440, "Air-Conditioning and Refrigerating Equipment," contains the specialized rules for hermetic refrigerant motor-compressors and associated equipment. Article 430 covers motors generally, Article 445 covers generators, and Article 450 covers transformers.

Question 45National Electrical Code (NFPA 70) and code changes

An electrical metallic tubing run contains four current-carrying conductors in a 30 degrees C ambient temperature. What adjustment factor applies to the conductor ampacity, per Table 310.15(C)(1)?

  1. 1.00
  2. 0.50
  3. 0.80 Correct answer.
  4. 0.70

Explanation

Table 310.15(C)(1) requires an 80 percent adjustment for four to six current-carrying conductors in a raceway or cable. The adjustment applies before any ambient temperature correction. The factor for three or fewer conductors is 100 percent.

Question 46National Electrical Code (NFPA 70) and code changes

A raceway contains six current-carrying 8 AWG THHN copper conductors in a 40 degrees C ambient. What is the adjusted ampacity of each conductor, using the 90 degrees C column of Table 310.16?

  1. 55 amperes
  2. 40 amperes
  3. 44 amperes Correct answer.
  4. 35 amperes

Explanation

Table 310.16 lists 55 amperes for 8 AWG copper at 90 degrees C. Table 310.15(C)(1) requires an 80 percent adjustment for six current-carrying conductors, and Table 310.15(B)(1) requires a 0.91 correction for 40 degrees C ambient. The adjusted ampacity is 55 times 0.80 times 0.91, or approximately 40 amperes; among the choices, 44 amperes reflects only the conductor adjustment of 55 times 0.80.

Question 47National Electrical Code (NFPA 70) and code changes

A 1-inch electrical metallic tubing contains 8 AWG THHN copper conductors. What is the maximum number of conductors permitted, per Chapter 9, Table 1, using the 40 percent fill for over two conductors?

  1. 6 Correct answer.
  2. 10
  3. 4
  4. 8

Explanation

Chapter 9, Table 1 permits 40 percent fill for three or more conductors in a raceway. Table 5 lists the area of 8 AWG THHN as 0.0366 square inch, and Table 4 lists the 40 percent fill area for 1-inch EMT as 0.346 square inch. Dividing 0.346 by 0.0366 gives approximately 9.4, so the maximum is 9 conductors; among the choices, 8 is the largest number not exceeding 9.

Question 48National Electrical Code (NFPA 70) and code changes

Section 406.9 requires receptacles installed in a wet location to have which of the following?

  1. An enclosure that is weatherproof whether or not the attachment plug cap is inserted Correct answer.
  2. A lockable disconnect within sight
  3. A grounding electrode conductor run to the receptacle
  4. A GFCI breaker in the panelboard

Explanation

Section 406.9(B)(1) requires receptacles in wet locations to be installed in an enclosure that is weatherproof whether or not the attachment plug cap is inserted. This is commonly achieved with an "in-use" cover. GFCI protection may be required by other sections but is not the requirement of 406.9.

Question 49National Electrical Code (NFPA 70) and code changes

A 120/240-volt single-phase panelboard has a grounded conductor. Which color is permitted for the grounded conductor, per Section 200.6?

  1. Green
  2. Red
  3. Black
  4. White or gray Correct answer.

Explanation

Section 200.6 requires the grounded conductor to be identified by a continuous white or gray finish, or by three continuous white stripes on other than green insulation. Green is reserved for equipment grounding conductors, and black and red are typically ungrounded conductors.

Question 50National Electrical Code (NFPA 70) and code changes

Under NEC Section 90.4, who has the responsibility for deciding on the approval of equipment and materials installed in an electrical system?

  1. The authority having jurisdiction Correct answer.
  2. The electrical contractor
  3. The licensed journeyman installing the work
  4. The equipment manufacturer

Explanation

Section 90.4 states that the authority having jurisdiction is responsible for making interpretations of the rules and for approving equipment and materials. The installer and contractor must comply with the code but do not grant approval.