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Question 1General Electrical Knowledge and Code Administration

Article 90 of the NEC states the purpose of the Code. Which of the following best describes that stated purpose?

  1. Setting product warranty requirements for electrical equipment
  2. Promoting the most economical wiring methods available
  3. Practical safeguarding of persons and property from hazards arising from electricity Correct answer.
  4. Establishing design specifications for electrical systems

Explanation

Article 90.1 states that the Code is intended to provide practical safeguarding of persons and property from hazards arising from the use of electricity. It is not a design manual, an economy guide, or a warranty document.

Question 2General Electrical Knowledge and Code Administration

According to Article 100, equipment is considered "listed" when it is which of the following?

  1. Inspected and approved in the field by the authority having jurisdiction
  2. Certified by the installing contractor as matching the drawings
  3. Included on a list published by a qualified organization that periodically evaluates production Correct answer.
  4. Accepted by the serving electric utility after a plan review

Explanation

Article 100 defines listed equipment as equipment included in a list published by an organization acceptable to the AHJ that maintains periodic inspection of production and states that the equipment meets a recognized standard.

Question 3General Electrical Knowledge and Code Administration

In a dwelling unit, which receptacles in a bathroom require ground-fault circuit-interrupter protection?

  1. Only receptacles serving hair dryers and similar appliances
  2. Only receptacles supplied from a 20-ampere circuit
  3. All 125-volt through 250-volt receptacles in the bathroom Correct answer.
  4. Only receptacles within 6 feet of the tub or shower

Explanation

Section 210.8(A) requires GFCI protection for all 125- through 250-volt receptacles installed in dwelling-unit bathrooms. The requirement is based on the room location, not on distance from the tub or on the appliance used.

Question 4General Electrical Knowledge and Code Administration

What is the ampacity of a 12 AWG copper THHN conductor where 75-degree C terminations are used, before any adjustment or correction factors?

  1. 25 A Correct answer.
  2. 30 A
  3. 35 A
  4. 20 A

Explanation

Table 310.16 lists 12 AWG copper at 25 amperes in the 75-degree C column, which applies where the terminations are rated 75 degrees C.

Question 5General Electrical Knowledge and Code Administration

What is the maximum rating of the overcurrent device permitted to protect a 14 AWG copper branch-circuit conductor?

  1. 15 A Correct answer.
  2. 30 A
  3. 25 A
  4. 20 A

Explanation

Section 240.4(D)(3) limits overcurrent protection for 14 AWG copper conductors to 15 amperes, even where a tabulated ampacity column shows a higher value.

Question 6General Electrical Knowledge and Code Administration

Which NEC article contains the general requirements for grounding and bonding?

  1. Article 200
  2. Article 215
  3. Article 250 Correct answer.
  4. Article 230

Explanation

Article 250 covers grounding and bonding, including system grounding, grounding electrodes, equipment grounding conductors, and bonding requirements.

Question 7General Electrical Knowledge and Code Administration

In general, when must an electrical permit be obtained for work that requires one?

  1. Any time before the circuit is energized
  2. Before the work covered by the permit begins Correct answer.
  3. Before the final inspection is scheduled
  4. After the rough-in wiring is complete

Explanation

A permit is normally obtained before any work begins so the installation can be inspected at the required stages, including rough-in before concealment.

Question 8General Electrical Knowledge and Code Administration

A metal box is marked with a capacity of 18.0 cubic inches. How many 12 AWG conductors may it contain, assuming no other items are installed in the box?

  1. 9
  2. 8 Correct answer.
  3. 6
  4. 7

Explanation

Table 314.16(B) assigns 2.25 cubic inches to each 12 AWG conductor, so 18.0 divided by 2.25 equals 8 conductors.

Question 9General Electrical Knowledge and Code Administration

Where a raceway contains more than two conductors, the conductors may fill no more than what percentage of the raceway's cross-sectional area?

  1. 53 percent
  2. 40 percent Correct answer.
  3. 31 percent
  4. 60 percent

Explanation

Chapter 9, Table 1 permits a 40 percent fill for raceways containing more than two conductors. The 53 percent value applies to one conductor and 31 percent to two conductors.

Question 10General Electrical Knowledge and Code Administration

Six current-carrying conductors are installed in a single raceway. What ampacity adjustment factor applies?

  1. 70 percent
  2. 90 percent
  3. 50 percent
  4. 80 percent Correct answer.

Explanation

Table 310.15(C)(1) applies an 80 percent adjustment factor where 4 through 6 current-carrying conductors are installed in a raceway or cable.

Question 11General Electrical Knowledge and Code Administration

In a dwelling unit, receptacle outlets along a wall must be placed so that no point along the floor line is more than what distance from a receptacle?

  1. 8 ft
  2. 4 ft
  3. 6 ft Correct answer.
  4. 5 ft

Explanation

Section 210.52(A)(1) requires receptacle outlets so that no point along the floor line of any wall space is more than 6 feet from a receptacle outlet.

Question 12General Electrical Knowledge and Code Administration

On a dwelling-unit kitchen countertop, what is the maximum distance from any point along the counter to a receptacle outlet?

  1. 18 in
  2. 12 in
  3. 24 in Correct answer.
  4. 36 in

Explanation

Section 210.52(C)(1) requires countertop receptacle outlets so that no point along the countertop is more than 24 inches from a receptacle.

Question 13General Electrical Knowledge and Code Administration

A rod-type grounding electrode must have a minimum length of which of the following?

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

Explanation

Section 250.52(A)(5) requires rod electrodes to be at least 8 feet in length and at least 5/8 inch in diameter unless listed otherwise.

Question 14General Electrical Knowledge and Code Administration

What is the minimum width of the working space in front of electrical equipment operating at 600 volts or less?

  1. 36 in
  2. 42 in
  3. 30 in Correct answer.
  4. 24 in

Explanation

Section 110.26(A)(2) requires the working space to be at least 30 inches wide, or the width of the equipment, whichever is greater.

Question 15General Electrical Knowledge and Code Administration

Using the general method, what unit lighting load does the Code assign to dwelling occupancies for the general lighting calculation?

  1. 3 VA per square foot Correct answer.
  2. 1 VA per square foot
  3. 2 VA per square foot
  4. 5 VA per square foot

Explanation

Table 220.12 sets the general lighting load for dwelling units at 3 volt-amperes per square foot of floor area.

Question 16General Electrical Knowledge and Code Administration

What is the minimum vertical clearance for service-drop conductors above a residential driveway?

  1. 10 ft
  2. 18 ft
  3. 12 ft Correct answer.
  4. 8 ft

Explanation

Table 230.24(B) requires 12 feet of clearance over residential driveways and commercial areas not subject to truck traffic.

Question 17General Electrical Knowledge and Code Administration

NM cable run through a bored hole in a wood stud must be kept at least what distance from the nearest edge of the stud, unless protected by a steel plate?

  1. 1-1/4 in Correct answer.
  2. 1 in
  3. 3/4 in
  4. 1-1/2 in

Explanation

Section 300.4(A)(1) requires the cable to be at least 1-1/4 inches from the nearest edge of the stud, or protected by a steel plate at least 1/16 inch thick.

Question 18General Electrical Knowledge and Code Administration

Which of the following provides running overload protection for a motor?

  1. The controller contactor
  2. A separate overload device selected under Article 430, Part III Correct answer.
  3. The motor disconnecting means
  4. The branch-circuit short-circuit and ground-fault protective device

Explanation

Part III of Article 430 covers overload protection, which protects the motor, its conductors, and the controller from overheating caused by overload. The branch-circuit device handles short circuits and ground faults.

Question 19General Electrical Knowledge and Code Administration

What is the minimum size copper equipment grounding conductor required for a circuit protected by a 60-ampere overcurrent device?

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

Explanation

Table 250.122 requires a 10 AWG copper equipment grounding conductor for a circuit protected at 60 amperes.

Question 20General Electrical Knowledge and Code Administration

Section 110.3(B) requires listed or labeled equipment to be installed in accordance with which of the following?

  1. Its listing and any instructions included in the listing or labeling Correct answer.
  2. The serving utility's connection requirements only
  3. The installing contractor's standard practices
  4. The least costly method permitted by the plans

Explanation

Section 110.3(B) requires equipment to be installed and used in accordance with any instructions included in the listing or labeling.

Question 21General Electrical Knowledge and Code Administration

What is the minimum size copper grounding electrode conductor for a service with 2/0 AWG copper service-entrance conductors?

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

Explanation

Table 250.66 requires a 4 AWG copper grounding electrode conductor where the largest copper service-entrance conductor is 2/0 or 3/0 AWG.

Question 22General Electrical Knowledge and Code Administration

Table 430.52 lists the maximum rating for an inverse-time circuit breaker providing branch-circuit short-circuit and ground-fault protection to a single motor as what percentage of the motor full-load current?

  1. 175 percent
  2. 200 percent
  3. 150 percent
  4. 250 percent Correct answer.

Explanation

Table 430.52 permits an inverse-time circuit breaker at up to 250 percent of motor full-load current for a single motor. The 175 percent figure applies to a dual-element time-delay fuse.

Question 23General Electrical Knowledge and Code Administration

Photovoltaic source circuit conductors must have an ampacity of not less than what percentage of the module short-circuit current, before any adjustment or correction factors?

  1. 150 percent
  2. 125 percent Correct answer.
  3. 175 percent
  4. 200 percent

Explanation

Section 690.8 requires PV source and output circuit conductors to be sized at 125 percent of the short-circuit current, accounting for continuous operation and irradiance.

Question 24General Electrical Knowledge and Code Administration

A dwelling unit has a general lighting load of 8,000 VA. Using the standard demand factors of Table 220.42, what is the calculated lighting demand?

  1. 4,200 VA
  2. 3,500 VA
  3. 4,750 VA Correct answer.
  4. 3,000 VA

Explanation

Table 220.42 applies 100 percent to the first 3,000 VA and 35 percent to the remainder, so 3,000 + 0.35 times 5,000 equals 4,750 VA.

Question 25General Electrical Knowledge and Code Administration

Under the 10-foot tap rule of 240.21(B)(1), the tap conductors must have an ampacity of not less than what fraction of the rating of the overcurrent device protecting the feeder?

  1. 1/10 Correct answer.
  2. 1/4
  3. 1/3
  4. 1/2

Explanation

Section 240.21(B)(1) requires tap conductors to have an ampacity of at least one-tenth the rating of the overcurrent device ahead of the tap, to be protected from physical damage, and to terminate in a single overcurrent device rated for the tap conductor ampacity.

Question 26Wiring Methods and Materials

Type NM cable installed in a dwelling must be secured at intervals not exceeding ___ and within ___ of every box, cabinet, or fitting.

  1. 4½ ft and 12 in Correct answer.
  2. 3 ft and 8 in
  3. 10 ft and 3 ft
  4. 6 ft and 12 in

Explanation

Section 334.30 requires Type NM cable to be secured at intervals not exceeding 4½ ft and within 12 in. of each box, cabinet, or fitting, except where the cable is fished. Keeping the support within 12 in. of the box prevents strain on the conductors at terminations.

Question 27Wiring Methods and Materials

Electrical metallic tubing must be securely fastened at intervals not exceeding ___ and within ___ of each box or fitting.

  1. 6 ft and 1 ft
  2. 12 ft and 5 ft
  3. 5 ft and 2 ft
  4. 10 ft and 3 ft Correct answer.

Explanation

Section 358.30 requires EMT to be fastened within 3 ft of each box or fitting and at intervals not exceeding 10 ft. Limited exceptions permit longer unsupported lengths at terminations where structural members do not provide a secure fastening point.

Question 28Wiring Methods and Materials

Where a raceway contains more than two conductors, the total cross-sectional area of all conductors may not exceed what percentage of the raceway interior cross-sectional area?

  1. 31 percent
  2. 53 percent
  3. 25 percent
  4. 40 percent Correct answer.

Explanation

Chapter 9, Table 1 permits 53 percent fill for a single conductor, 31 percent for two conductors, and 40 percent for over two conductors. Most branch circuits and feeders fall into the 40 percent row used for conduit fill calculations.

Question 29Wiring Methods and Materials

Which cable type is listed for installation as a direct-buried wiring method without a raceway?

  1. Type AC cable
  2. Type UF cable Correct answer.
  3. Type MC cable
  4. Type NM cable

Explanation

Article 340 lists Type UF (underground feeder) cable as suitable for direct burial, installed at the cover depths given in Table 300.5. Its conductors and jacket are rated for direct contact with earth and moisture.

Question 30Wiring Methods and Materials

An insulated equipment grounding conductor 6 AWG and smaller must be identified by which color?

  1. Orange
  2. Green or green with one or more yellow stripes Correct answer.
  3. Black with a red stripe
  4. White or gray

Explanation

Section 250.119 requires insulated equipment grounding conductors 6 AWG and smaller to be green or green with one or more yellow stripes; a bare conductor is also permitted in many cases. The green-with-yellow option allows a grounding conductor to remain distinguishable where green is used for another purpose.

Question 31Wiring Methods and Materials

A box installed in a wall of concrete, tile, or other noncombustible material may not be recessed more than what distance from the finished surface?

  1. 3/16 inch
  2. 1/4 inch Correct answer.
  3. 1/2 inch
  4. 1/8 inch

Explanation

Section 314.20 limits the setback of a box in a noncombustible wall or ceiling to 1/4 in. unless the box is listed for a greater setback or a listed extension ring is installed. A deeper recess leaves the box inaccessible to the finished surface.

Question 32Wiring Methods and Materials

What is the allowable ampacity of 10 AWG copper THHN conductors connected to 75°C-rated terminals?

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

Explanation

THHN is a 90°C-rated conductor, but the ampacity used may not exceed the lowest temperature rating of the terminations. Table 310.16 lists 35 A for 10 AWG copper at 75°C, and that is the value applied here.

Question 33Wiring Methods and Materials

Type NM cable is permitted to be installed in which of the following locations?

  1. Concealed in a dry interior wall of a dwelling Correct answer.
  2. In a duct or plenum used for environmental air
  3. In a Class I, Division 1 location
  4. In a wet location outdoors

Explanation

Section 334.10 permits Type NM cable in one- and two-family dwellings and similar structures, and 334.12 prohibits it in wet locations, ducts and plenums, and hazardous locations. Concealed dry wall cavities are a standard permitted use.

Question 34Wiring Methods and Materials

A box contains six 12 AWG current-carrying conductors and two 12 AWG equipment grounding conductors. There are no devices, clamps, or fittings in the box. What minimum box volume is required?

  1. 15.75 in³ Correct answer.
  2. 18.00 in³
  3. 13.50 in³
  4. 11.25 in³

Explanation

Section 314.16(B) assigns 2.25 in³ to each 12 AWG conductor and counts one or more equipment grounding conductors as a single conductor. Six circuit conductors at 2.25 in³ give 13.50 in³, plus 2.25 in³ for the grounding conductors totals 15.75 in³.

Question 35Wiring Methods and Materials

A service is supplied by 2/0 AWG copper service-entrance conductors, and the grounding electrode conductor runs to a metal underground water pipe. What is the minimum size copper grounding electrode conductor?

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

Explanation

Table 250.66 sizes the grounding electrode conductor by the circular mil area of the largest service-entrance conductor; both 2/0 and 3/0 copper require 4 AWG copper. The 6 AWG cap in 250.66(A) applies only to rod, pipe, and plate electrodes, not to a water pipe electrode.

Question 36Wiring Methods and Materials

A 200 A overcurrent device protects a feeder run in a raceway with copper conductors. What is the minimum size copper equipment grounding conductor required?

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

Explanation

Table 250.122 sizes the equipment grounding conductor from the rating of the overcurrent device protecting the circuit. A 200 A device requires 6 AWG copper or 4 AWG aluminum.

Question 37Wiring Methods and Materials

The total cross-sectional area of conductors installed in a wireway may not exceed what percentage of the interior cross-sectional area at any point?

  1. 60 percent
  2. 25 percent
  3. 20 percent Correct answer.
  4. 40 percent

Explanation

Section 376.22(A) limits the sum of the conductor cross-sectional areas to 20 percent of the wireway interior area at any cross section. Section 376.22(B) separately limits the number of current-carrying conductors for ampacity adjustment.

Question 38Wiring Methods and Materials

Schedule 40 PVC conduit in trade sizes 1/2 through 1 must be supported at intervals not exceeding what distance?

  1. 3 ft Correct answer.
  2. 5 ft
  3. 8 ft
  4. 6 ft

Explanation

Table 352.30 requires PVC conduit in trade sizes 1/2 through 1 to be supported at intervals not exceeding 3 ft, with longer spacings permitted as the trade size increases. Section 352.30 also requires a support within 3 ft of each box or termination.

Question 39Wiring Methods and Materials

Liquidtight flexible metal conduit must be securely fastened at intervals not exceeding what distance?

  1. 3 ft
  2. 4½ ft Correct answer.
  3. 10 ft
  4. 6 ft

Explanation

Section 350.30(A) requires liquidtight flexible metal conduit to be fastened within 12 in. of each box or fitting and at intervals not exceeding 4½ ft. Longer unsupported runs can sag and damage the metallic core and jacket.

Question 40Wiring Methods and Materials

Bends in Type NM cable must have an inner edge radius of not less than how many times the cable diameter?

  1. 7 times
  2. 3 times
  3. 10 times
  4. 5 times Correct answer.

Explanation

Section 334.24 requires the inner radius of any bend in Type NM cable to be at least five times the cable diameter. This prevents damage to the conductors and the outer jacket during and after installation.

Question 41Wiring Methods and Materials

What is the maximum number of 12 AWG THHN conductors permitted in a ½ in. electrical metallic tubing?

  1. 8
  2. 7
  3. 9 Correct answer.
  4. 6

Explanation

Chapter 9, Table 1 limits fill to 40 percent where more than two conductors are installed, and each 12 AWG THHN conductor has an approximate area of 0.0133 in². For ½ in. EMT, that calculation and Chapter 9, Table C.1 both allow nine conductors.

Question 42Wiring Methods and Materials

A raceway contains eight current-carrying conductors. What ampacity adjustment factor applies?

  1. 70 percent Correct answer.
  2. 50 percent
  3. 60 percent
  4. 80 percent

Explanation

Table 310.15(C)(1) requires a 70 percent adjustment for 7 through 9 current-carrying conductors installed in a raceway or cable. The adjustment is applied to the conductor ampacity from Table 310.16 before comparing the result with the load.

Question 43Wiring Methods and Materials

Type UF cable supplying a detached garage with a 30 A feeder is buried directly in earth. What is the minimum cover required?

  1. 36 in
  2. 24 in Correct answer.
  3. 30 in
  4. 12 in

Explanation

Table 300.5 requires 24 in. of cover for direct-buried cables and conductors. The reduced 12 in. depth is available only to residential branch circuits rated 120 V or less, 20 A or less, and protected by ground-fault circuit-interrupter protection, so a 30 A feeder does not qualify.

Question 44Wiring Methods and Materials

What is the smallest copper conductor permitted to be installed in parallel in a feeder?

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

Explanation

Section 310.10(H) permits conductors to be installed in parallel only where they are 1/0 AWG or larger and meet the matching requirements for size, length, material, and insulation. Smaller conductors must be installed as single runs.

Question 45Wiring Methods and Materials

Which of the following raceways is permitted to serve as an equipment grounding conductor without an installed wire-type conductor?

  1. Liquidtight flexible nonmetallic conduit
  2. Rigid polyvinyl chloride conduit
  3. Electrical metallic tubing Correct answer.
  4. Electrical nonmetallic tubing

Explanation

Section 250.118 lists electrical metallic tubing among the metallic raceways recognized as equipment grounding conductors, provided the couplings and fittings maintain a continuous path. Nonmetallic raceways are not recognized for this purpose and require a separate equipment grounding conductor.

Question 46Wiring Methods and Materials

A 3 in. raceway enters and leaves a junction box in a straight run, and conductors are pulled through the box. What is the minimum box dimension measured in the direction of the pull?

  1. 24 in Correct answer.
  2. 20 in
  3. 12 in
  4. 16 in

Explanation

Section 314.28(A)(1) requires the box length to be at least eight times the trade size of the largest raceway for a straight pull. Eight times 3 in. equals 24 in.

Question 47Wiring Methods and Materials

A single 2 in. raceway enters a box and turns 90 degrees. What is the minimum distance from the raceway entry to the opposite wall of the box?

  1. 12 in Correct answer.
  2. 14 in
  3. 18 in
  4. 24 in

Explanation

Section 314.28(A)(2) requires the distance between raceways enclosing the same conductor in an angle or U pull to be at least six times the trade size of the larger raceway. For a single 2 in. raceway, that is 6 × 2 in. = 12 in.; where additional raceways enter in the same row, their trade sizes are added to that dimension.

Question 48Wiring Methods and Materials

A box contains four 12 AWG ungrounded conductors, two 12 AWG grounded conductors, one 12 AWG equipment grounding conductor, one cable clamp, and one duplex receptacle. What minimum box volume is required?

  1. 20.25 in³
  2. 15.75 in³
  3. 18.00 in³
  4. 22.50 in³ Correct answer.

Explanation

Under Section 314.16(B), each 12 AWG conductor counts 2.25 in³, so six circuit conductors equal 13.50 in³. One clamp adds 2.25 in³, the grounding conductor counts once at 2.25 in³, and the strap-mounted receptacle counts as two conductors at 4.50 in³, for a total of 22.50 in³.

Question 49Wiring Methods and Materials

Where circuit conductors are increased in size to reduce voltage drop, the equipment grounding conductor must be:

  1. replaced with a bonding jumper sized per 250.102
  2. increased in size proportionally Correct answer.
  3. reduced because the circuit voltage drop is now lower
  4. sized from Table 250.122 only

Explanation

Section 250.122(B) requires the equipment grounding conductor to be increased in size proportionally whenever the circuit conductors are increased for any reason other than ampacity, such as voltage drop. The ratio of the circular mil area of the installed conductors to the minimum required area is applied to the grounding conductor.

Question 50Wiring Methods and Materials

A service is supplied by 500 kcmil copper conductors. What is the minimum size copper supply-side bonding jumper?

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

Explanation

Table 250.102(C)(1) sizes the supply-side bonding jumper from the largest ungrounded service conductor. Copper service conductors over 350 kcmil through 600 kcmil require a 1/0 AWG copper supply-side bonding jumper.