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NJ Registered Journeyman Electrician practice questions

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Question 1Electrical contracting practice and theory (official content outline not published in source)

A 120/240-volt single-phase dwelling service supplies a 9,600 VA fixed electric space-heating load and a 4,500 VA cooking appliance. Under the standard NEC optional calculation for a dwelling, what demand factor may be applied to the heating load when the air-conditioning load is smaller?

  1. 75 percent
  2. 100 percent Correct answer.
  3. 50 percent
  4. 65 percent

Explanation

The optional dwelling calculation permits the larger of the heating or air-conditioning load to be taken at 100 percent, while the smaller of the two is omitted entirely. No percentage reduction applies to the heating load itself in this method.

Question 2Electrical contracting practice and theory (official content outline not published in source)

A 40-ampere, 240-volt branch circuit supplies a single household electric range. What minimum conductor ampacity does the branch-circuit conductor require when the range nameplate specifies 40 amperes?

  1. 40 amperes Correct answer.
  2. 24 amperes
  3. 32 amperes
  4. 20 amperes

Explanation

Branch-circuit conductors for a household range must have an ampacity not less than the rating of the branch-circuit overcurrent device, which is sized to the nameplate. Since the nameplate calls for 40 amperes, the conductors must carry 40 amperes.

Question 3Electrical contracting practice and theory (official content outline not published in source)

Which conductor material is permitted for use as an equipment grounding conductor in a rigid metal conduit installation where the conduit itself already serves as the grounding path?

  1. A copper conductor sized per the equipment grounding conductor table Correct answer.
  2. A steel conductor installed without corrosion protection
  3. A conductor with green insulation used as an ungrounded feeder
  4. An aluminum conductor smaller than 4 AWG

Explanation

Where a supplemental equipment grounding conductor is installed, it must be sized from the equipment grounding conductor table and be of an acceptable material. Copper is always permitted. Aluminum is restricted to sizes 4 AWG and larger, and green insulation identifies a grounding conductor, not an ungrounded feeder.

Question 4Electrical contracting practice and theory (official content outline not published in source)

A feeder supplying a panelboard in a commercial building carries a continuous load of 80 amperes and a noncontinuous load of 50 amperes. The terminals are rated 75 degrees C. What is the minimum feeder overcurrent device rating, assuming the conductors are sized to match?

  1. 125 amperes
  2. 150 amperes Correct answer.
  3. 175 amperes
  4. 130 amperes

Explanation

Continuous loads must be taken at 125 percent, giving 100 amperes, plus the 50-ampere noncontinuous load for a total of 150 amperes. The next standard size may only be used when conductor ampacity and terminal ratings allow it, and 150 amperes is already a standard rating.

Question 5Electrical contracting practice and theory (official content outline not published in source)

In a 3-phase, 4-wire, 208Y/120-volt system, what color is required for the grounded conductor of a service-entrance set of conductors?

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

Explanation

The grounded conductor of a service must be identified with white or natural gray finish along its entire length. Green is reserved for equipment grounding conductors, orange identifies a high-leg ungrounded conductor, and black is an ungrounded conductor.

Question 6Electrical contracting practice and theory (official content outline not published in source)

A 200-ampere service disconnecting means is installed outdoors on a dwelling. What is the maximum permitted height of the center of the operating handle above the finished grade?

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

Explanation

Service disconnecting means must be readily accessible, and the center of the operating handle may not be more than 6 feet 7 inches above the floor or grade. This limit keeps the handle operable without a ladder or portable means.

Question 7Electrical contracting practice and theory (official content outline not published in source)

A 60-ampere, 240-volt single-phase feeder supplies a subpanel 150 feet from the main service. Voltage drop is a design consideration rather than a mandatory code limit. Which conductor size best limits the voltage drop to about 3 percent for this load?

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

Explanation

Voltage drop is proportional to conductor resistance and length, so a 60-ampere load over 150 feet requires a substantially larger conductor than the minimum ampacity size. Of the choices, 4 AWG copper provides the lowest resistance and best approximates a 3 percent drop.

Question 8Electrical contracting practice and theory (official content outline not published in source)

What is the minimum working clearance required in front of a 480-volt panelboard with exposed live parts on one side and no live parts or grounded surfaces on the opposite side?

  1. 4 feet
  2. 3 feet 6 inches
  3. 5 feet
  4. 3 feet Correct answer.

Explanation

For conditions where exposed live parts are on one side and no live or grounded parts are on the other, the minimum clear distance for 480-volt equipment is 3 feet. Greater distances apply when grounded or live surfaces face the working space.

Question 9Electrical contracting practice and theory (official content outline not published in source)

A luminaire is installed in a clothes closet. Which location is permitted for a surface-mounted incandescent fixture?

  1. Directly above the shelf within 12 inches of the shelf edge
  2. On the ceiling directly over the storage area
  3. On the wall above the door opening Correct answer.
  4. Within the closet storage space near hanging garments

Explanation

Closet lighting restrictions prohibit luminaires within the storage space and too close to shelving where stored goods could contact them. A surface-mounted fixture on the wall above the door opening is outside the defined storage space and is permitted.

Question 10Electrical contracting practice and theory (official content outline not published in source)

A 15-ampere, 125-volt receptacle is installed in a wet location on a commercial patio. Which enclosure type is required for the receptacle?

  1. A standard plastic faceplate
  2. An open-bottom junction box
  3. A gasketed cover that must be opened to insert a cord
  4. A weatherproof cover that remains closed with a cord inserted Correct answer.

Explanation

Receptacles in wet locations require an enclosure that is weatherproof whether or not the attachment plug cap is inserted. A cover that stays closed around the cord maintains the weatherproof integrity during use.

Question 11Electrical contracting practice and theory (official content outline not published in source)

A 3-phase, 460-volt motor has a nameplate full-load current of 34 amperes. What is the minimum ampacity of the branch-circuit conductors supplying the motor alone?

  1. 42.5 amperes Correct answer.
  2. 60 amperes
  3. 50 amperes
  4. 34 amperes

Explanation

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the motor full-load current from the appropriate table. One hundred twenty-five percent of 34 amperes is 42.5 amperes.

Question 12Electrical contracting practice and theory (official content outline not published in source)

What is the maximum standard rating of the overcurrent device protecting a 10 AWG copper conductor with 60 degrees C insulation, where the load is not a motor and the termination is rated 60 degrees C?

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

Explanation

A 10 AWG copper conductor with 60 degrees C insulation has an ampacity of 30 amperes, and the overcurrent device may not exceed that ampacity. The termination temperature rating limits the usable ampacity to the 60 degrees C column.

Question 13Electrical contracting practice and theory (official content outline not published in source)

A dwelling unit has a 1,500 square foot floor area. What is the minimum general lighting load in volt-amperes for the service calculation?

  1. 5,000 VA
  2. 4,500 VA Correct answer.
  3. 6,000 VA
  4. 3,000 VA

Explanation

The general lighting load for a dwelling is calculated at 3 volt-amperes per square foot. Multiplying 1,500 square feet by 3 gives 4,500 volt-amperes before any demand factors are applied.

Question 14Electrical contracting practice and theory (official content outline not published in source)

An electrical contractor installs a 100-ampere feeder to a detached garage. Which of the following is required for the equipment grounding conductor between the buildings when a separate grounding electrode is installed at the garage?

  1. Bond the grounded conductor to the equipment grounding conductor at the garage
  2. Use the grounded conductor as the equipment grounding path
  3. Omit all grounding at the detached structure
  4. Install an equipment grounding conductor with the feeder Correct answer.

Explanation

For a feeder to a separate building, an equipment grounding conductor must be run with the feeder conductors and bonded to the grounding electrode system at the separate structure. The grounded conductor may not be used as the grounding path.

Question 15Electrical contracting practice and theory (official content outline not published in source)

A 20-ampere branch circuit supplies a bathroom receptacle outlet in a dwelling. Which protection method is required for the receptacle?

  1. Neither GFCI nor AFCI
  2. Arc-fault circuit-interrupter protection only
  3. Both GFCI and AFCI protection
  4. Ground-fault circuit-interrupter protection Correct answer.

Explanation

All 125-volt, single-phase, 15- and 20-ampere receptacle outlets in dwelling bathrooms require ground-fault circuit-interrupter protection. AFCI protection is generally required for branch circuits supplying outlets in dwelling living areas, but bathroom receptacles are governed by the GFCI requirement.

Question 16Electrical contracting practice and theory (official content outline not published in source)

A 480-volt, 3-phase motor branch circuit is protected by a 70-ampere inverse-time circuit breaker. The motor controller is marked with a maximum rating of 60 amperes. What is the maximum rating of the disconnecting means permitted if it is a non-fused safety switch?

  1. 100 amperes
  2. 60 amperes Correct answer.
  3. 70 amperes
  4. 115 amperes

Explanation

A motor disconnecting means must be rated at least 115 percent of the motor full-load current and must be capable of interrupting the locked-rotor current. It may not exceed the rating marked on the controller, so 60 amperes is the maximum here.

Question 17Electrical contracting practice and theory (official content outline not published in source)

A commercial kitchen has a 12 kW, 208-volt, 3-phase commercial electric cooking appliance. What is the approximate full-load current for sizing the branch-circuit conductors?

  1. 50 amperes
  2. 83 amperes
  3. 58 amperes
  4. 33 amperes Correct answer.

Explanation

For a balanced 3-phase load, current equals watts divided by the product of the square root of three and the line voltage. Dividing 12,000 VA by 1.732 times 208 volts yields approximately 33 amperes.

Question 18Electrical contracting practice and theory (official content outline not published in source)

A feeder supplies a continuous 50-ampere load and a noncontinuous 40-ampere load. The overcurrent device is rated 100 amperes. What minimum conductor ampacity is required before any adjustment or correction factors?

  1. 112.5 amperes
  2. 90 amperes
  3. 102.5 amperes Correct answer.
  4. 100 amperes

Explanation

Feeder conductors must be sized at 125 percent of the continuous load plus 100 percent of the noncontinuous load. That gives 62.5 plus 40, or 102.5 amperes, which is the minimum conductor ampacity.

Question 19Electrical contracting practice and theory (official content outline not published in source)

What is the minimum size copper equipment grounding conductor required for a 400-ampere feeder circuit using conductors larger than 250 kcmil?

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

Explanation

For overcurrent devices rated 400 amperes, the equipment grounding conductor table requires a minimum of 3 AWG copper, and for circuits with overcurrent protection above 400 amperes up to 800 amperes, 1/0 copper applies. For a 400-ampere device the table value is 3 AWG; among the choices, 3/0 is the only listed size at or above the minimum that is commonly specified for large feeders.

Question 20Electrical contracting practice and theory (official content outline not published in source)

A recessed luminaire is installed in a ceiling where the space above is used as an air-handling plenum. Which marking must the luminaire bear?

  1. A marking indicating it is listed for wet locations
  2. A marking indicating it is suitable for damp locations only
  3. A marking indicating it is for recessed installation only
  4. A marking indicating it is suitable for use in a plenum Correct answer.

Explanation

Luminaires installed in air-handling plenums must be listed for that use and marked accordingly. A general recessed or damp-location marking does not establish suitability for a plenum environment.

Question 21Electrical contracting practice and theory (official content outline not published in source)

A 3-phase, 4-wire, 120/208-volt panelboard has a 120-volt, 20-ampere branch circuit supplying a commercial garage receptacle. Which protection is required for this receptacle outlet?

  1. No special protection
  2. AFCI protection only
  3. Surge protection
  4. Ground-fault circuit-interrupter protection for personnel Correct answer.

Explanation

Receptacle outlets in commercial garages require ground-fault circuit-interrupter protection for personnel because of the presence of vehicles and possible wet conditions. AFCI or surge protection does not satisfy this requirement.

Question 22Electrical contracting practice and theory (official content outline not published in source)

A transformer has a primary rated 480 volts and a secondary rated 120/240 volts. The secondary is a 3-wire, single-phase system. Which statement about grounding the secondary is correct for a separately derived system?

  1. The secondary may be left ungrounded in all cases
  2. The secondary grounded conductor must be bonded to a grounding electrode at the transformer Correct answer.
  3. The secondary requires no grounding electrode if the primary is grounded
  4. The primary grounded conductor serves as the secondary grounding connection

Explanation

For a separately derived system, the grounded conductor of the secondary must be bonded to the grounding electrode system at the source, typically at the transformer. The primary grounding does not substitute for secondary grounding.

Question 23Electrical contracting practice and theory (official content outline not published in source)

A 240-volt, single-phase, 5 kW electric water heater is installed in a dwelling. What is the minimum branch-circuit conductor ampacity required, treating the load as continuous?

  1. 20.8 amperes
  2. 26 amperes Correct answer.
  3. 31.3 amperes
  4. 40 amperes

Explanation

Current equals 5,000 watts divided by 240 volts, or about 20.8 amperes, and a continuous load requires 125 percent, giving about 26 amperes. Conductors must have an ampacity of at least 26 amperes.

Question 24Electrical contracting practice and theory (official content outline not published in source)

A feeder supplying a 100-ampere subpanel is installed in a raceway with an ambient temperature of 50 degrees C. The conductors are 1/0 THHN copper with 90 degrees C insulation. What correction factor applies to the conductor ampacity for this ambient temperature?

  1. 0.82 Correct answer.
  2. 0.71
  3. 0.91
  4. 1.00

Explanation

For 90 degrees C insulated conductors in a 50 degrees C ambient, the correction factor is 0.82. It is selected from the insulation-rating column and ambient-temperature range, so conductor gauge and the 100-ampere panel rating do not change this factor.

Question 25Electrical contracting practice and theory (official content outline not published in source)

A 20-ampere branch circuit supplies a dwelling bedroom. Which protection is required for the branch-circuit conductors?

  1. Ground-fault circuit-interrupter protection only
  2. Arc-fault circuit-interrupter protection Correct answer.
  3. Neither AFCI nor GFCI
  4. Surge protection

Explanation

Branch circuits supplying outlets in dwelling bedrooms require arc-fault circuit-interrupter protection to reduce the risk of fire from arcing faults. GFCI protection addresses shock and does not replace this requirement.

Question 26Electrical contracting practice and theory (official content outline not published in source)

A 120/240-volt, single-phase dwelling service uses a 4-wire feeder to a subpanel. Under the National Electrical Code, which conductor must be bonded to the panelboard enclosure at the subpanel?

  1. Neither conductor, because the subpanel is a separate structure
  2. Both the grounded neutral and the equipment grounding conductor
  3. The grounded neutral conductor only
  4. The equipment grounding conductor only Correct answer.

Explanation

For a subpanel fed from a service, the equipment grounding conductor terminates on the grounding bus and is bonded to the enclosure; the grounded neutral must remain isolated from the enclosure so neutral current does not travel on grounding paths. Neutral-to-enclosure bonding occurs only at the service disconnecting means (or at the source of a separately derived system).

Question 27Electrical contracting practice and theory (official content outline not published in source)

A 125-volt, 20-ampere branch circuit supplies a single receptacle outlet in a commercial building. What is the minimum permitted ampere rating of that receptacle?

  1. 50 amperes
  2. 30 amperes
  3. 20 amperes Correct answer.
  4. 15 amperes

Explanation

A single receptacle on an individual branch circuit must have an ampere rating not less than the branch-circuit rating. On a 20-ampere circuit, a 15-ampere single receptacle would be undersized, so a 20-ampere receptacle is the minimum.

Question 28Electrical contracting practice and theory (official content outline not published in source)

A dwelling unit kitchen has two 20-ampere small-appliance branch circuits. What is the minimum number of 20-ampere small-appliance branch circuits required for the kitchen, pantry, and dining area combined?

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

Explanation

The code requires at least two 20-ampere small-appliance branch circuits to serve receptacle outlets in the kitchen, pantry, dining room, and similar areas. These circuits may also supply other permitted outlets but cannot serve lighting outlets.

Question 29Electrical contracting practice and theory (official content outline not published in source)

A 240-volt, single-phase resistance heating unit draws 40 amperes continuously. What is the minimum ampacity of the branch-circuit conductors supplying it?

  1. 60 amperes
  2. 32 amperes
  3. 50 amperes Correct answer.
  4. 40 amperes

Explanation

Fixed electric space-heating equipment is treated as a continuous load, so branch-circuit conductors must have an ampacity of at least 125 percent of the load. 40 amperes times 1.25 equals 50 amperes.

Question 30Electrical contracting practice and theory (official content outline not published in source)

A 3-phase, 208-volt feeder supplies a balanced load of 60 kVA. What is the approximate line current?

  1. 288 amperes
  2. 500 amperes
  3. 208 amperes
  4. 167 amperes Correct answer.

Explanation

For a balanced three-phase load, current equals volt-amperes divided by the product of the square root of three and the line voltage. 60,000 VA divided by (1.732 times 208 V) equals approximately 167 amperes.

Question 31Electrical contracting practice and theory (official content outline not published in source)

A 480-volt, 3-phase motor has a nameplate full-load current of 52 amperes. What is the minimum ampacity of the motor branch-circuit conductors, assuming no adjustment factors apply?

  1. 52 amperes
  2. 104 amperes
  3. 78 amperes
  4. 65 amperes Correct answer.

Explanation

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the motor full-load current from the applicable table, not the nameplate value. Using the table value for a 480-volt motor near this rating, 125 percent of 52 amperes is 65 amperes.

Question 32Electrical contracting practice and theory (official content outline not published in source)

An electrician is installing a 200-ampere, 240-volt single-phase feeder to a separate building. Which conductor may be used as the equipment grounding conductor if the feeder uses a metal raceway?

  1. The white conductor of a 3-wire cable
  2. A white insulated conductor sized to the neutral
  3. The metal raceway itself Correct answer.
  4. The grounded neutral conductor

Explanation

A metal raceway is permitted to serve as the equipment grounding conductor when installed in accordance with the code and when continuity is assured. The grounded neutral is never acceptable as an equipment grounding conductor on the load side of the service.

Question 33Electrical contracting practice and theory (official content outline not published in source)

A 20-ampere branch circuit supplies a commercial garage. Which protection is required for the receptacle outlets in the garage?

  1. Both GFCI and AFCI protection
  2. Neither GFCI nor AFCI protection
  3. Ground-fault circuit-interrupter protection Correct answer.
  4. Arc-fault circuit-interrupter protection

Explanation

Receptacle outlets in commercial garages are among the locations requiring ground-fault circuit-interrupter protection for personnel. AFCI protection is generally required for dwelling-unit branch circuits, not commercial garages.

Question 34Electrical contracting practice and theory (official content outline not published in source)

A 100-ampere, 240-volt feeder supplies a subpanel in a detached garage. What is the minimum size copper conductor required if the conductors are THWN and the ambient temperature is 30 degrees C?

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

Explanation

A 100-ampere feeder requires conductors with an ampacity of at least 100 amperes after any correction or adjustment. Using 75 degrees C terminals and standard tables, 3 AWG copper is the minimum size that provides at least 100 amperes, while 4 AWG is rated below that.

Question 35Electrical contracting practice and theory (official content outline not published in source)

A 480-volt, 3-phase motor is controlled by a magnetic starter. What is the maximum permitted rating of the branch-circuit short-circuit and ground-fault protective device if the motor has a marked code letter and the device is an inverse-time circuit breaker?

  1. 250 percent of full-load current Correct answer.
  2. 150 percent of full-load current
  3. 400 percent of full-load current
  4. 175 percent of full-load current

Explanation

For a standard inverse-time circuit breaker protecting a motor branch circuit, the maximum setting is generally 250 percent of the motor full-load current, with higher settings permitted only when the device will not carry the starting current.

Question 36Electrical contracting practice and theory (official content outline not published in source)

A dwelling unit has a 12 kW electric range. What minimum branch-circuit rating is required for the range?

  1. 50 amperes
  2. 60 amperes
  3. 30 amperes
  4. 40 amperes Correct answer.

Explanation

For a household electric range rated 12 kW or less, the branch-circuit rating may be based on the nameplate demand rather than the connected load. A 12 kW range at 240 volts draws 50 amperes, but the code permits a 40-ampere branch circuit for ranges up to 12 kW under the demand factors in the table.

Question 37Electrical contracting practice and theory (official content outline not published in source)

A luminaire is installed over a bathtub in a dwelling bathroom. Which condition must be met for the installation to be permitted?

  1. The luminaire must be listed for damp locations and be at least 8 feet above the tub rim Correct answer.
  2. The luminaire must be controlled by a wall switch outside the bathroom
  3. The luminaire must be listed for wet locations
  4. The luminaire must be of the recessed type

Explanation

Luminaires installed over a bathtub or shower must be listed for damp locations and, where subject to shower spray, for wet locations, and they must be installed at least 8 feet above the rim of the tub.

Question 38Electrical contracting practice and theory (official content outline not published in source)

A service entrance uses 500 kcmil copper conductors. What is the minimum size copper grounding electrode conductor required for a metal water pipe electrode?

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

Explanation

The grounding electrode conductor for a metal water pipe is sized from the table based on the largest service-entrance conductor. For 500 kcmil copper, the table requires 2/0 AWG copper.

Question 39Electrical contracting practice and theory (official content outline not published in source)

A 120-volt, 15-ampere branch circuit supplies a dwelling living room. Which protection is required for the branch-circuit conductors?

  1. Arc-fault circuit-interrupter protection Correct answer.
  2. Ground-fault circuit-interrupter protection
  3. Combination AFCI and GFCI protection
  4. No special protection

Explanation

Branch circuits supplying dwelling-unit living rooms, bedrooms, and similar areas require arc-fault circuit-interrupter protection. GFCI protection is required only in specific locations such as bathrooms and kitchens.

Question 40Electrical contracting practice and theory (official content outline not published in source)

An electrical contractor is installing a 200-ampere service in a dwelling. What is the minimum size of the service-entrance conductors if copper THWN is used with 75 degrees C terminals?

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

Explanation

Service-entrance conductors must have an ampacity of at least the service rating. At 75 degrees C, 3/0 AWG copper provides at least 200 amperes, while 2/0 AWG is rated below that.

Question 41Electrical contracting practice and theory (official content outline not published in source)

A 3-phase, 480-volt motor has a nameplate full-load current of 28 amperes. What is the minimum size copper conductor required for the branch circuit, assuming 75 degrees C terminations?

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

Explanation

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the full-load current from the table, which is 35 amperes here. At 75 degrees C, 10 AWG copper is rated 35 amperes and is the minimum size that satisfies the requirement.

Question 42Electrical contracting practice and theory (official content outline not published in source)

A dwelling unit has a 2,400 square foot floor area. Using the general lighting load of 3 VA per square foot, what is the minimum general lighting load?

  1. 7,200 VA Correct answer.
  2. 9,600 VA
  3. 4,800 VA
  4. 12,000 VA

Explanation

The general lighting load is calculated by multiplying the floor area by 3 volt-amperes per square foot for a dwelling unit. 2,400 square feet times 3 VA equals 7,200 VA.

Question 43Electrical contracting practice and theory (official content outline not published in source)

A 60-ampere, 240-volt single-phase feeder supplies a subpanel. What is the minimum size copper equipment grounding conductor required if the conductors are in a nonmetallic raceway?

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

Explanation

The equipment grounding conductor is sized from the overcurrent device rating. For a 60-ampere circuit, the table requires 10 AWG copper as the minimum equipment grounding conductor.

Question 44Electrical contracting practice and theory (official content outline not published in source)

A 240-volt, single-phase, 4.5 kW electric water heater is installed in a dwelling. What is the minimum branch-circuit conductor ampacity required?

  1. 28.1 amperes
  2. 37.5 amperes
  3. 18.75 amperes
  4. 23.4 amperes Correct answer.

Explanation

The water heater draws 4,500 VA divided by 240 volts, or 18.75 amperes. Because it is a continuous load, the conductor ampacity must be at least 125 percent of that value, which is approximately 23.4 amperes.

Question 45Electrical contracting practice and theory (official content outline not published in source)

A feeder supplying a 100-ampere subpanel is installed in a raceway with an ambient temperature of 50 degrees C. The conductors are THWN-2 copper. What correction factor applies to the conductor ampacity?

  1. 0.58
  2. 0.82
  3. 0.71 Correct answer.
  4. 1.00

Explanation

For 75 degrees C and 90 degrees C conductors in a 50 degrees C ambient, the correction factor is 0.71. The factor reduces the allowable ampacity to account for the elevated temperature.

Question 46Electrical contracting practice and theory (official content outline not published in source)

A 20-ampere branch circuit supplies a bathroom receptacle in a dwelling. Which protection method is required for the receptacle outlet?

  1. No protection is required
  2. Ground-fault circuit-interrupter protection Correct answer.
  3. Arc-fault circuit-interrupter protection
  4. Both GFCI and AFCI protection

Explanation

Bathroom receptacle outlets in dwelling units require ground-fault circuit-interrupter protection for personnel. AFCI protection is not the governing requirement for bathroom receptacles.

Question 47Electrical contracting practice and theory (official content outline not published in source)

A 3-phase, 4-wire, 120/208-volt panelboard supplies a 120-volt, 20-ampere branch circuit to a commercial garage receptacle. Which protection is required for the receptacle?

  1. Ground-fault circuit-interrupter protection Correct answer.
  2. Arc-fault circuit-interrupter protection
  3. Both GFCI and AFCI protection
  4. Neither GFCI nor AFCI protection

Explanation

Receptacle outlets in commercial garages require ground-fault circuit-interrupter protection. AFCI protection is not the requirement for this commercial location.

Question 48Electrical contracting practice and theory (official content outline not published in source)

A 480-volt, 3-phase motor branch circuit is protected by a 70-ampere inverse-time circuit breaker. What is the minimum size copper conductor required if the full-load current is 52 amperes?

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

Explanation

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the full-load current, which is 65 amperes here. At 75 degrees C, 6 AWG copper is rated 65 amperes and satisfies the requirement.

Question 49Electrical contracting practice and theory (official content outline not published in source)

A dwelling unit has a 1,500 square foot floor area and a 12 kW range. What is the minimum general lighting load in volt-amperes?

  1. 3,000 VA
  2. 4,500 VA Correct answer.
  3. 6,000 VA
  4. 7,500 VA

Explanation

The general lighting load for a dwelling unit is 3 volt-amperes per square foot. 1,500 square feet times 3 VA equals 4,500 VA; the range load is separate and does not change the lighting calculation.

Question 50Electrical contracting practice and theory (official content outline not published in source)

A 120-volt, 20-ampere branch circuit supplies a dwelling bedroom. Which protection is required for the branch-circuit conductors?

  1. No protection is required
  2. Ground-fault circuit-interrupter protection
  3. Arc-fault circuit-interrupter protection Correct answer.
  4. Both GFCI and AFCI protection

Explanation

Branch circuits supplying dwelling-unit bedrooms require arc-fault circuit-interrupter protection. GFCI protection is not the governing requirement for bedroom receptacles.