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Question 1General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Article 100 defines "listed" as equipment, materials, or services that meet which description?

  1. Inspected on the job site and found acceptable by the authority having jurisdiction
  2. Included in a list published by an organization acceptable to the authority having jurisdiction and concerned with product evaluation, where the listing states the item meets a designated standard or has been tested and found suitable for a specified purpose Correct answer.
  3. Approved for one specific installation by the serving electric utility
  4. Marked by the manufacturer as suitable for general electrical use without further evaluation

Explanation

Article 100 defines listed in terms of a listing organization acceptable to the AHJ that maintains periodic inspection of production and publishes a list of evaluated items. The listing must state that the item either meets a designated standard or has been tested and found suitable for a specified purpose. Field inspection by the AHJ, manufacturer claims, or utility approval do not meet the definition.

Question 2General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Article 100 defines a continuous load as a load in which the maximum current is expected to continue for how long?

  1. 30 minutes or more
  2. The full 24-hour operating day
  3. 1 hour or more
  4. 3 hours or more Correct answer.

Explanation

Article 100 defines a continuous load as one where the maximum current is expected to continue for 3 hours or more. This definition drives the 125 percent sizing rules applied to conductors and overcurrent devices serving such loads. Shorter durations are treated as noncontinuous loads.

Question 3General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Under Article 100, who qualifies as a "qualified person"?

  1. Anyone who has completed a registered apprenticeship program
  2. Anyone holding a journeyman electrician license issued by any state
  3. Anyone designated in writing by the building owner to operate electrical equipment
  4. One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved Correct answer.

Explanation

Article 100 defines a qualified person by demonstrated skills and knowledge plus safety training on the hazards involved, not by a credential alone. Licensing or apprenticeship completion may be evidence of training, but the definition turns on demonstrated ability and hazard recognition. An owner's designation alone does not make a person qualified.

Question 4General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Section 110.12 requires that electrical equipment be installed in which manner?

  1. Only after the permit has been posted on site
  2. At the lowest installed cost consistent with the plans
  3. By a licensed electrical contractor
  4. In a neat and workmanlike manner Correct answer.

Explanation

Section 110.12 states that electrical equipment shall be installed in a neat and workmanlike manner. Informational notes describe accepted industry practices such as those published by NECA and other organizations. Licensing, cost, and permit administration are outside the scope of this section.

Question 5General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

What is the minimum required width of the working space in front of electrical equipment?

  1. The width of the equipment or 24 inches, whichever is greater
  2. The width of the equipment or 30 inches, whichever is greater Correct answer.
  3. The width of the equipment or 36 inches, whichever is greater
  4. The width of the equipment or 48 inches, whichever is greater

Explanation

Section 110.26(A)(2) requires the working space width to be the width of the equipment or 30 inches, whichever is greater. The space must also permit at least a 90-degree opening of equipment doors or hinged panels. The 30-inch figure is a minimum, not a fixed dimension when the equipment is wider.

Question 6General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

The working space in front of electrical equipment must extend from the floor to what minimum height?

  1. 7 feet
  2. 8 feet
  3. 6 1/2 feet Correct answer.
  4. 5 feet

Explanation

Section 110.26(A)(3) requires the working space to extend from grade, floor, or platform to a height of 6 1/2 feet or the height of the equipment, whichever is greater. This headroom applies to the full depth and width of the required working space.

Question 7General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

A 480Y/277-volt panelboard is installed where exposed live parts are on one side of the working space and a grounded metal surface is on the other. What minimum depth of working space is required?

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

Explanation

For equipment operating at 251 to 600 volts to ground under Condition 2, Table 110.26(A)(1) requires a depth of 4 feet. The 277-volt line-to-ground value places the installation in the 251-to-600-volt column. Condition 3 would require 5 feet, and Condition 1 would require 3 feet.

Question 8General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

What space above electrical equipment must be reserved as dedicated electrical space?

  1. A space 3 feet above the equipment, extending 12 inches beyond its width and depth
  2. A space from the floor to 6 feet above the equipment, with the full width and depth of the equipment Correct answer.
  3. A space 8 feet above the equipment, extending 24 inches beyond its width and depth
  4. A space from the floor to the structural ceiling regardless of height, extending 6 inches beyond the equipment depth

Explanation

Section 110.26(E)(1) dedicates the space equal to the width and depth of the equipment and extending from the floor to a height of 6 feet above the equipment or to the structural ceiling, whichever is lower. That dedicated space may not be used for foreign systems such as piping, ducts, or leak-prone equipment.

Question 9General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

How must a disconnecting means for electrical equipment be identified?

  1. It must be marked with the available fault current at its terminals
  2. It must be marked with the date of installation and the name of the installing contractor
  3. It must be legibly marked to indicate its purpose unless it is located and arranged so the purpose is evident Correct answer.
  4. It must be marked with the conductor size and the rating of the overcurrent device

Explanation

Section 110.22(A) requires each disconnecting means to be legibly marked to indicate its purpose unless it is located and arranged so its purpose is evident. The marking must be durable enough to withstand the environment. Installation dates, fault current, and conductor sizes are addressed by other sections.

Question 10General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

The arc-flash hazard warning required by 110.16 applies to equipment meeting which description?

  1. Only equipment operating at more than 1000 volts
  2. Equipment supplied through more than one service disconnect
  3. Equipment in other than dwelling units that is likely to require examination, adjustment, servicing, or maintenance while energized Correct answer.
  4. Any equipment installed outdoors in a wet location, regardless of voltage

Explanation

Section 110.16 requires a field-applied warning label on equipment that is likely to require examination, adjustment, servicing, or maintenance while energized, and the requirement applies to installations other than dwelling units. The label alerts qualified persons to arc-flash hazard and available information. It is not limited by voltage class or by the number of service disconnects.

Question 11General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Section 110.14 addresses tightening of electrical connections. Which practice complies?

  1. Tightening terminals to the torque marked on the equipment or in the manufacturer's instructions, using a calibrated torque tool where the instructions require it Correct answer.
  2. Tightening terminals to the maximum torque the terminal material can withstand
  3. Tightening terminals to the value printed in the connector catalog for the largest conductor the terminal accepts
  4. Tightening terminals only as firmly as can be done by hand plus one-quarter turn

Explanation

Section 110.14(D) requires terminals to be tightened to the torque indicated on the equipment or in the manufacturer's instructions, and where a tightening torque is indicated, a calibrated torque tool must be used unless the instructions specify otherwise. Connection torque is a listing and labeling condition for the terminal and conductor combination.

Question 12General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Equipment intended to interrupt current at fault levels must have an interrupting rating at nominal circuit voltage that is at least equal to what value?

  1. The available fault current at the load terminals of the equipment
  2. The rating of the next upstream overcurrent device
  3. The ampacity of the conductors supplying the equipment
  4. The maximum current that is available at the line terminals of the equipment Correct answer.

Explanation

Section 110.9 requires equipment intended to interrupt current at fault levels to have an interrupting rating at nominal circuit voltage at least equal to the current available at its line terminals. This ensures the device can safely clear a fault at the point where it is installed. Conductor ampacity and upstream device ratings do not establish that value.

Question 13General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Section 110.24 requires service equipment to be legibly marked in the field with which value?

  1. The interrupting rating of the service disconnecting means
  2. The calculated arc-flash boundary distance
  3. The maximum available fault current Correct answer.
  4. The minimum available fault current at the load terminals

Explanation

Section 110.24(A) requires service equipment in other than dwelling units to be marked with the maximum available fault current. The marking must be durable and be updated when system changes alter the available fault current. Arc-flash boundaries and device ratings are not what this section requires on the label.

Question 14General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

According to 110.26(B), how may the working space required in front of electrical equipment be used?

  1. It shall not be used for storage Correct answer.
  2. It may be used for storage if a clear path of at least 24 inches is maintained
  3. It shall be used to store the maintenance equipment for the building
  4. It may be used to store spare parts if the parts are noncombustible

Explanation

Section 110.26(B) states that working space required by the section shall not be used for storage. The space must remain clear so that qualified persons can safely work on the equipment. When normally enclosed live parts are exposed for servicing, the working space must also be suitably guarded if it is in a passageway or general open space.

Question 15General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

For switchgear rated 1200 amperes or more and more than 6 feet wide, 110.26(C)(2) generally requires which arrangement?

  1. Two entrances, one at each end of the working space Correct answer.
  2. A single entrance at least 24 inches wide located at one end of the equipment
  3. Two entrances only when the equipment is rated more than 1000 volts
  4. Three entrances evenly spaced along the working space

Explanation

Section 110.26(C)(2) requires large equipment rated 1200 amperes or more and over 6 feet wide to have at least two means of egress, one at each end of the working space. Limited exceptions permit a single entrance under specified conditions, such as unobstructed exit travel. The requirement addresses the difficulty of escaping a large equipment lineup in an emergency.

Question 16General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Section 110.26(D) requires illumination for working spaces about which equipment?

  1. Only equipment located in rooms without natural light
  2. Indoor service equipment, switchboards, switchgear, panelboards, and motor control centers Correct answer.
  3. Only equipment operating at more than 600 volts
  4. Only equipment rated 1200 amperes or more

Explanation

Section 110.26(D) requires illumination to be provided for all working spaces about indoor service equipment, switchboards, switchgear, panelboards, and motor control centers. The lighting must not be controlled solely by an automatic means that could leave the space dark while someone is working. Voltage, room daylight, and ampere rating do not limit the requirement.

Question 17General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Working space is provided in front of a 208Y/120-volt panelboard with exposed live parts on one side and a concrete block wall directly opposite. Which condition governs the required depth of working space?

  1. The depth cannot be determined without the available fault current
  2. Condition 2 Correct answer.
  3. Condition 3
  4. Condition 1

Explanation

Table 110.26(A)(1) uses Condition 2 where exposed live parts are on one side and grounded parts are on the other, and concrete, brick, and tile walls are treated as grounded. Condition 1 requires the opposite side to be free of live or grounded parts, while Condition 3 requires exposed live parts on both sides. Fault current does not affect which condition applies.

Question 18General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Which statement correctly distinguishes the grounded conductor from the equipment grounding conductor?

  1. Both conductors must be identified with white or gray insulation over their entire length
  2. The grounded conductor is bonded to equipment enclosures and normally carries no current
  3. The grounded conductor is a circuit conductor that is intentionally grounded and carries current in normal operation, while the equipment grounding conductor normally carries no current Correct answer.
  4. The equipment grounding conductor carries the circuit's unbalanced current during normal operation

Explanation

Article 100 defines the grounded conductor as a system or circuit conductor that is intentionally grounded and that normally carries current, while the equipment grounding conductor is the conductive path that connects normally non-current-carrying metal parts and normally carries current only under fault conditions. Confusing the two roles leads to improper bonding and neutral identification.

Question 19General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Section 110.10 requires that overcurrent protective devices, total impedance, component short-circuit current ratings, and other circuit characteristics be selected and coordinated so that which result is achieved?

  1. The circuit protective devices will clear a fault without extensive damage to the circuit components Correct answer.
  2. The conductors are protected against overloads only
  3. The equipment grounding conductor will carry fault current continuously
  4. The available fault current is reduced to zero at the load end of the circuit

Explanation

Section 110.10 requires protective devices, impedance, and short-circuit current ratings to be selected and coordinated so the circuit protective devices clear a fault without extensive damage to circuit components. This is a performance requirement separate from the interrupting rating rule of 110.9. It also covers components listed for use only on circuits capable of delivering no more than a specified fault current.

Question 20General Requirements, Definitions, and Inspection (NEC Articles 100, 110)

Which option best matches the Article 100 definition of "readily accessible"?

  1. Reachable after removing a bolted panel cover with a screwdriver
  2. Reachable from a portable ladder kept in a nearby utility closet
  3. Capable of being reached quickly for operation, renewal, or inspections without climbing over or removing obstacles or using portable ladders Correct answer.
  4. Reachable only by qualified persons wearing arc-rated protective equipment

Explanation

Article 100 defines readily accessible as capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders. The concept concerns speed and freedom from obstacles, not who is permitted to gain access. Locations requiring tools, ladders, or removal of building finishes are not readily accessible.

Question 21Wiring Methods and Materials (NEC Chapter 3)

Type NM cable must be secured within what maximum distance of a box or fitting, and at what maximum intervals along the run?

  1. Within 12 in of the box and at intervals not exceeding 4 1/2 ft Correct answer.
  2. Within 8 in of the box and at intervals not exceeding 4 1/2 ft
  3. Within 12 in of the box and at intervals not exceeding 6 ft
  4. Within 6 in of the box and at intervals not exceeding 10 ft

Explanation

Section 334.30 requires Type NM cable to be secured and supported at intervals not exceeding 4 1/2 ft and within 12 in of every box, cabinet, or fitting. Limited exceptions exist, such as cable fished into a concealed space or cable secured by listed staples in accessible attic spaces. Both the interval and the box distance must be satisfied.

Question 22Wiring Methods and Materials (NEC Chapter 3)

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

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

Explanation

Section 358.30 limits EMT support intervals to 10 ft and requires a support within 3 ft of each box, conduit body, or termination fitting. The 3 ft rule keeps the raceway rigid near terminations so the fitting is not stressed. Both conditions must be met.

Question 23Wiring Methods and Materials (NEC Chapter 3)

How much box volume must be counted for each 12 AWG conductor in a box?

  1. 2.25 cu in Correct answer.
  2. 2.00 cu in
  3. 1.75 cu in
  4. 2.50 cu in

Explanation

Table 314.16(B) assigns a volume allowance based on conductor size: 2.0 cu in for 14 AWG, 2.25 cu in for 12 AWG, and 2.5 cu in for 10 AWG. Each conductor that enters the box, plus specified items counted as conductors, uses one allowance. The total must not exceed the volume marked on the box.

Question 24Wiring Methods and Materials (NEC Chapter 3)

Each free conductor in an outlet or junction box must be at least ___ long, and must extend at least ___ beyond the opening of the box.

  1. 6 in; 1 in
  2. 6 in; 3 in Correct answer.
  3. 3 in; 6 in
  4. 4 in; 2 in

Explanation

Section 300.14 requires at least 6 in of free conductor measured from the point in the box where it emerges from its raceway or cable sheath. At least 3 in of that conductor must extend outside the box opening. This provides enough conductor to splice or terminate equipment.

Question 25Wiring Methods and Materials (NEC Chapter 3)

What is the maximum total number of degrees of bends permitted in a run of raceway between pull points?

  1. 360 degrees Correct answer.
  2. 90 degrees
  3. 270 degrees
  4. 180 degrees

Explanation

Sections such as 358.26 for EMT and 344.26 for rigid metal conduit limit the bends between boxes, conduit bodies, or fittings to a total of 360 degrees. This includes offsets, kicks, and saddle bends. The limit exists so the raceway can still be pulled without damaging conductors.

Question 26Wiring Methods and Materials (NEC Chapter 3)

Type UF cable is listed for installation in which locations?

  1. Wet, damp, and dry locations Correct answer.
  2. Dry and damp locations only
  3. Dry locations only
  4. Damp locations only

Explanation

Article 340 permits Type UF cable in wet, damp, and dry locations, and it is permitted for direct burial where the burial requirements of 300.5 are met. The conductors are enclosed in a moisture-resistant assembly suitable for underground use. It is also permitted in corrosive locations where identified for the purpose.

Question 27Wiring Methods and Materials (NEC Chapter 3)

Flexible metal conduit must be securely fastened within what maximum distance of a box or fitting?

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

Explanation

Section 348.30 requires FMC to be fastened within 12 in of each box or fitting and at intervals not exceeding 4 1/2 ft, with exceptions for short lengths. The 12 in dimension keeps the flexible raceway from pulling out of terminations. Listed fittings and supports must be used.

Question 28Wiring Methods and Materials (NEC Chapter 3)

Type AC cable is distinguished from Type MC cable by the presence of which feature?

  1. A bare copper equipment grounding conductor
  2. A bare aluminum bonding strip in contact with the armor Correct answer.
  3. A plastic inner jacket around the circuit conductors
  4. An overall nonmetallic outer sheath

Explanation

Type AC cable contains a bare aluminum bonding strip that is in intimate contact with the interlocked metal armor, so the armor assembly serves as the equipment grounding path. Type MC cable normally relies on a separate insulated equipment grounding conductor or an armor listed for grounding. That bonding strip is the defining internal difference between the two cable types.

Question 29Wiring Methods and Materials (NEC Chapter 3)

Type MC cable must be supported at intervals not exceeding ___ and within ___ of a box or fitting.

  1. Every 6 ft and within 6 in
  2. Every 4 1/2 ft and within 12 in
  3. Every 6 ft and within 12 in Correct answer.
  4. Every 10 ft and within 3 ft

Explanation

Section 330.30 requires Type MC cable to be secured and supported at intervals not exceeding 6 ft and within 12 in of every box or fitting. The longer interval reflects the greater rigidity of the metal-clad assembly compared with NM or AC cable. Exception provisions apply to certain short lengths and to cable in cable trays.

Question 30Wiring Methods and Materials (NEC Chapter 3)

Where conductors are spliced in a run of EMT, the splice must be ___.

  1. left accessible inside the raceway
  2. supported within 12 in of the splice
  3. enclosed in a box or conduit body Correct answer.
  4. made with an irreversible compression tool

Explanation

Section 300.15 requires a box, conduit body, or other listed enclosure at every splice, pull point, or termination point. A splice cannot simply be pulled into the raceway because the enclosure keeps the connection protected and accessible. Support of the splice itself is not what the rule requires.

Question 31Wiring Methods and Materials (NEC Chapter 3)

The conductors, splices, and taps in a metal wireway may fill the interior cross-sectional area to a maximum of ___.

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

Explanation

Section 376.22 limits conductors, splices, and taps in a wireway to 20 percent of the interior cross-sectional area. The generous physical space of a wireway is intended partly for heat dissipation and future additions. Ampacity adjustment for current-carrying conductors also applies once the count exceeds 30 in a cross section.

Question 32Wiring Methods and Materials (NEC Chapter 3)

A straight run of 1 in Schedule 40 PVC conduit must be supported at intervals not exceeding ___.

  1. 3 ft Correct answer.
  2. 5 ft
  3. 3 1/2 ft
  4. 4 ft

Explanation

Table 352.30 gives support intervals that increase with conduit size: 3 ft for 1/2 through 1 in, 3 1/2 ft for 1 1/4 through 2 in, 4 ft for 2 1/2 through 3 in, 4 1/2 ft for 3 1/2 through 5 in, and 5 ft for 6 in. PVC needs closer support than metal raceways because it is less rigid. Section 352.30 also requires a support within 3 ft of each box.

Question 33Wiring Methods and Materials (NEC Chapter 3)

A cable is run through a bored hole less than 1 1/4 in from the nearest edge of a wood framing member. Protection must be provided by a steel plate not less than ___ thick.

  1. 1/8 in
  2. 1/32 in
  3. 1/4 in
  4. 1/16 in Correct answer.

Explanation

Section 300.4(A)(1) requires a steel plate at least 1/16 in thick when a hole or notch is less than 1 1/4 in from the nearest edge of a stud, joist, or similar member. The plate prevents nails and screws from penetrating the cable or raceway. Protection may be omitted where the cable is otherwise listed for the condition.

Question 34Wiring Methods and Materials (NEC Chapter 3)

Type UF cable supplied by a 120/240 V, 20 A branch circuit is direct buried beneath a one-family dwelling driveway used only for dwelling-related purposes. What is the minimum cover?

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

Explanation

Table 300.5 contains a specific row for one- and two-family dwelling driveways and outdoor parking areas used only for dwelling-related purposes, requiring 18 in of cover. The general 12 in allowance applies to residential branch circuits not run beneath a driveway. Deeper cover is required under public streets and roads.

Question 35Wiring Methods and Materials (NEC Chapter 3)

Cut ends of rigid metal conduit and intermediate metal conduit must be ___ before the raceway is assembled.

  1. painted to prevent corrosion
  2. chamfered with a file to a 45 degree bevel
  3. threaded over the full length of the cut
  4. reamed or otherwise finished to remove burrs Correct answer.

Explanation

Sections 344.28 and 342.28 require all cut ends to be reamed or otherwise finished to remove rough edges before the conduit is installed. Burrs left in the raceway can cut conductor insulation during a pull. The requirement applies to both field cuts and factory cuts.

Question 36Wiring Methods and Materials (NEC Chapter 3)

An expansion fitting must be installed in a run of rigid PVC conduit where thermal expansion and contraction will cause a length change of at least ___.

  1. 1/4 in Correct answer.
  2. 1/8 in
  3. 1/2 in
  4. 1 in

Explanation

Section 352.44 requires expansion fittings to compensate for thermal expansion and contraction where the length change will be 1/4 in or more. The change is calculated from the run length, the temperature differential, and the expansion coefficient of the PVC. Runs with smaller movement do not require expansion fittings.

Question 37Wiring Methods and Materials (NEC Chapter 3)

The radius of the inner edge of a bend in Type NM cable must not be less than ___ the diameter of the cable.

  1. 8 times
  2. 10 times
  3. 3 times
  4. 5 times Correct answer.

Explanation

Section 334.24 requires bends in NM cable to have an inner radius of at least five times the cable diameter. The same rule appears for other cable articles and protects the conductors and jacket from damage. Bends made tighter than this can crack the sheath or stress the conductors.

Question 38Wiring Methods and Materials (NEC Chapter 3)

Which of the following locations is acceptable for the installation of electrical metallic tubing?

  1. Where subject to severe physical damage
  2. In a wet location Correct answer.
  3. In an area subject to severe corrosive vapors
  4. In a hazardous (classified) location

Explanation

Article 358 permits EMT to be installed exposed, concealed, and in wet locations, provided corrosion-resistant supports and fittings are used. Section 358.12 prohibits EMT where it would be subject to severe physical damage, in hazardous (classified) locations, and where it would be subject to corrosive conditions that damage the tubing. Wet locations therefore remain an acceptable use.

Question 39Wiring Methods and Materials (NEC Chapter 3)

Boxes and conduit bodies must be installed so that ___.

  1. their locations are recorded in the panelboard directory
  2. the wiring inside is accessible without removing building finish Correct answer.
  3. the covers are mounted a minimum of 12 in above the floor
  4. they are supported independently of the raceway system

Explanation

Section 314.29 requires boxes and conduit bodies to be installed so that the wiring inside is accessible without removing any part of the building finish or structure. Accessibility permits future inspection, repair, and modification. Support requirements in 314.23 are a separate concern.

Question 40Wiring Methods and Materials (NEC Chapter 3)

For a straight pull, the length of a box or conduit body in the direction of the pull must be at least ___ the trade size of the largest raceway.

  1. four times
  2. six times
  3. eight times Correct answer.
  4. ten times

Explanation

Section 314.28(A)(1) requires the length of a box or conduit body in the direction of a straight pull to be at least eight times the trade size of the largest raceway. The dimension is measured from the raceway entry to the opposite wall. This space allows conductors to be pulled without damage.

Question 41Wiring Methods and Materials (NEC Chapter 3)

The same conductors enter a box through a 3 in raceway on one wall and leave through a 2 in raceway on an adjacent wall. What is the minimum required distance between the two raceway entries?

  1. 24 in
  2. 18 in Correct answer.
  3. 12 in
  4. 16 in

Explanation

For an angle pull, Section 314.28(A)(2) requires the distance between raceway entries enclosing the same conductors to be at least six times the trade size of the larger raceway. Here 6 times 3 in equals 18 in. The distance is measured along the inside of the box between the nearest edges of the raceways.

Question 42Wiring Methods and Materials (NEC Chapter 3)

Six current-carrying THHN conductors are installed in a single raceway. The ampacity of each conductor must be adjusted to what percentage of its Table 310.16 value?

  1. 80 percent Correct answer.
  2. 75 percent
  3. 50 percent
  4. 70 percent

Explanation

Table 310.15(C)(1) requires ampacity adjustment when more than three current-carrying conductors are installed together. For four through six conductors the adjustment factor is 80 percent. Conductors that are not current-carrying, such as a neutral in a balanced multiwire branch circuit, are generally excluded from the count.

Question 43Wiring Methods and Materials (NEC Chapter 3)

A 4 in by 1 1/2 in square metal box is used for a splice. It contains no cable clamps, no devices, and no equipment grounding conductors. How many 12 AWG conductors may the box contain?

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

Explanation

Table 314.16(A) assigns a 4 in by 1 1/2 in square box a volume of 21.0 cu in. Each 12 AWG conductor requires 2.25 cu in under Table 314.16(B), and 21.0 divided by 2.25 equals 9.33, which rounds down to 9 conductors. Clamps, devices, and grounding conductors would consume additional volume.

Question 44Wiring Methods and Materials (NEC Chapter 3)

Type UF cable is direct buried beneath a public street. What minimum cover is required?

  1. 18 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 installed under streets, highways, roads, alleys, driveways, and parking lots. The reduced residential allowances do not apply to public roadways. Raceways in those locations are permitted shallower cover than direct-buried cable.

Question 45Wiring Methods and Materials (NEC Chapter 3)

Where all other conditions of the NEC are satisfied, flexible metal conduit may serve as an equipment grounding conductor only if its length does not exceed ___.

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

Explanation

Article 348 permits FMC to serve as an equipment grounding conductor only where the conditions of 250.118 are met, including a length limit of 6 ft and termination in listed fittings. Beyond that length the fault-current path through the flexible armor is not considered reliable. A separate equipment grounding conductor is then required.

Question 46Wiring Methods and Materials (NEC Chapter 3)

Liquidtight flexible nonmetallic conduit (Type LFNC-B) is permitted to be installed in which of the following situations?

  1. Encased within a concrete slab that is in direct contact with the earth
  2. Exposed on a building exterior where it is subject to physical damage
  3. Inside a concealed location within a plenum ceiling without any listing marking
  4. Buried directly in the earth where the conduit is listed and marked for direct burial Correct answer.

Explanation

Type LFNC-B is a listed raceway that may be installed in exposed, concealed, and underground locations when the raceway is listed and marked for the specific use, including direct burial. Where subject to physical damage, the raceway must be protected by guards or be of a type identified for the condition.

Question 47Wiring Methods and Materials (NEC Chapter 3)

A 1 1/2 in trade size rigid metal conduit nipple, 18 in long, is installed between two cabinets to protect a short raceway run. What minimum number of supports is required for this nipple?

  1. Two supports, one at each end
  2. No support is required for the nipple Correct answer.
  3. One support is required at the midpoint of the nipple
  4. Supports are required every 5 ft along the nipple

Explanation

Rigid metal conduit must be supported in accordance with the support spacing table, but a nipple of 3 ft or less in length is exempt from the support requirements. Because the 18 in nipple is shorter than 3 ft, no support is needed.

Question 48Wiring Methods and Materials (NEC Chapter 3)

A run of nonmetallic sheathed cable is installed through the attic of a dwelling and must pass across the top of ceiling joists where the attic is accessible only by a scuttle. Which installation satisfies the physical protection requirement?

  1. The cable is secured to the top edge of the joists with staples spaced 12 in apart
  2. The cable is laid across the top of the joists and secured with cable ties at each joist
  3. The cable is run through bored holes in the joists instead of across their tops Correct answer.
  4. The cable is run across the joists and covered with a 1/4 in plywood walkway

Explanation

In attics and roof spaces that are accessible, cable run across the top of floor joists, or within 6 ft of the scuttle, must be protected from physical damage; the usual acceptable method is to run the cable through bored holes in the framing members. Running the cable through holes in the joists avoids the exposure entirely.

Question 49Overcurrent Protection, Grounding, and Bonding (NEC Articles 240, 250)

Which of the following is a standard ampere rating for an inverse-time circuit breaker, as listed in NEC 240.6(A)?

  1. 130 A
  2. 110 A Correct answer.
  3. 115 A
  4. 145 A

Explanation

Section 240.6(A) lists the standard ampere ratings for fuses and inverse-time circuit breakers, and 110 A appears in that list. The values 115 A, 130 A, and 145 A are not standard ratings, so a device so marked would not be a standard-size overcurrent device.

Question 50Overcurrent Protection, Grounding, and Bonding (NEC Articles 240, 250)

A homeowner asks you to install a panelboard containing branch-circuit breakers inside a bathroom. How does the NEC address this?

  1. Permitted where it is installed at least 3 ft from the bathtub
  2. Permitted where the panelboard is protected by a GFCI receptacle
  3. Permitted where the panelboard enclosure has a lockable cover
  4. Prohibited in bathrooms by 240.24 Correct answer.

Explanation

Section 240.24 identifies bathrooms as a location where overcurrent devices are not permitted, in addition to clothes closets and similar spaces. GFCI protection, clearance, or a lockable cover does not change that prohibition.