NEC 2020 Code Questions Practice Test 4

Question 1: A single family dwelling unit has a connected load of 4000 VA. which of the following is the calculated demand load?

• 3350 VA
• 3550 VA
• 4000 VA
• 3850 VA

NEC Reference: NEC 220.42

Question 2: What is the adjustment ampacity of a 3/0 THWN conductor at an ambient temperature of 108⁰F in wet location. The raceway contains four 3/0 THWN conductors in it.

• 119 amperes
• 144 amperes
• 153 amperes
• 133 amperes

NEC Reference: NEC 310.15(B)(16)

Question 3: In a dwelling unit has an electric heater rated at 5040 watts at 240 volts. What of the circuit breaker is used to protect the circuit?

• 20 amperes
• 21 amperes
• 24 amperes
• 25 ampere

Question 4: Which of the following locations type NM cable can be permitted to use?

• As a service entrance cable
• In storage battery rooms
• In elevators or escalators
• one and two family dwelling units

NEC Reference: NEC 334.12

Question 5: In an underground service a bare neutral conductor can be buried in the ground with out any insulation.

• True
• False

NEC Reference: NEC 230.30

Question 6: When two or more single phase electric ranges are supplied by a 3 phase , 4 wire feeder, the total load computed is on the basis of ………………………….

• Twice the maximum number connected between any two phases
• Four times the maximum number connected between any two phases
• Three times the maximum number connected to a single phase

NEC Reference: NEC 250.55

Question 7: What is the unit load per square foot in volt ampere for a restaurant?

• 2 VA
• 1 VA
• 3 VA
• 1 1/2 VA

NEC Reference: NEC 220.12

Question 8: What is permissible voltage drop in percentage for feeders at the farthest outlet of power heating and lighting loads?

• 3 %
• 2 %
• 4 %
• 5 %

NEC Reference: NEC 215.2(A)(4)

Question 9: At least one 15 or 20 ampere receptacle should be located within 50 feet of electrical service applies to outdoor service equipment.

• True
• False

Question 10: The overall length of the power supply cards for mobile homes shall not be less than ………… feet

• 20 feet
• 36 ½ feet
• 25 feet
• 34 feet

NEC Reference: NEC 550.10(D)

Question 11: In other than dwelling units, GFCI protection is required for 125 volt through 250 volt receptacles in commercial and institutional kitchens. This requirement is found in:

• NEC 210.8(A)
• NEC 210.8(B)
• NEC 240.4
• NEC 300.5

NEC Reference: NEC 210.8(B)

Question 12: Overhead conductors for outside branch circuits and feeders installed above a roof must maintain a minimum clearance of:

• 3 feet
• 8 feet
• 15 feet
• 20 feet

NEC Reference: NEC 225.19(A)

Question 13: Open (overhead) service conductors must maintain a minimum clearance from windows designed to be opened of:

• 1 foot
• 3 feet
• 5 feet
• 10 feet

NEC Reference: NEC 230.9(A)

Question 14: Under the 10-foot tap rule, tap conductors are not required to have overcurrent protection at the point of supply if the tap conductor length does not exceed 10 feet and the tap conductors have an ampacity of not less than:

• The combined computed load supplied
• 10% of the feeder rating only
• Any size is permitted
• Half the feeder OCPD rating

NEC Reference: NEC 240.21(B)(1)

Question 15: The connection of a grounding electrode conductor to a grounding electrode must be:

• Accessible
• Always buried and inaccessible
• Painted over for protection
• Located inside a sealed conduit only

NEC Reference: NEC 250.68(A)

Question 16: At each outlet, junction, or switch point, free conductor of not less than what length must be left for splices or device connections?

• 3 inches
• 6 inches
• 9 inches
• 12 inches

NEC Reference: NEC 300.14

Question 17: An outlet box intended to support a ceiling-suspended (paddle) fan must be:

• Listed for the purpose of supporting a ceiling fan
• Any standard lighting outlet box
• A plastic remodel box only
• No special box is required

NEC Reference: NEC 314.27(C)

Question 18: NM (nonmetallic-sheathed) cable is prohibited from being used in which of the following locations?

• Embedded in poured concrete
• In a one-family dwelling wall cavity
• In an attic with no physical damage exposure
• Fished through a finished wall

NEC Reference: NEC 334.12

Question 19: Rigid metal conduit (RMC) is permitted to be used in which of the following environments, provided it is suitably protected against corrosion?

• Wet and corrosive locations, if suitably protected
• RMC may never be used outdoors
• Only dry indoor locations
• Never in concrete

NEC Reference: NEC 344.10

Question 20: The fill requirements for cables installed in a cable tray are found in which NEC article?

• Article 392
• Article 250
• Article 110
• Article 90

NEC Reference: NEC 392.22

Question 21: An AC general-use snap switch is permitted to control a resistive and inductive load not exceeding what maximum rating of the switch?

• The ampere rating of the switch
• Half the ampere rating of the switch
• Twice the ampere rating of the switch
• There is no limit

NEC Reference: NEC 404.14(A)

Question 22: When replacing a receptacle where a grounding means exists in the box, the replacement receptacle must generally be:

• A grounding-type receptacle, connected to the equipment ground
• Any non-grounding receptacle is always acceptable
• A two-prong receptacle only
• No connection to ground is ever required

NEC Reference: NEC 406.4(D)

Question 23: A luminaire installed in a wet location, such as under an open porch roof exposed to rain, must be marked:

• "Suitable for Wet Locations"
• "Suitable for Dry Locations Only"
• No marking is required
• "Indoor Use Only"

NEC Reference: NEC 410.10(A)

Question 24: Unless otherwise specified elsewhere in Article 422, the branch-circuit overcurrent device for a household appliance must have a rating that is:

• In accordance with the appliance rating
• Always exactly 15 amperes
• Never required
• Always double the appliance rating

NEC Reference: NEC 422.11(A)

Question 25: For sizing motor branch-circuit conductors, ampacity, and overcurrent protection, full-load current values must be taken from:

• The NEC full-load current tables
• The motor nameplate current, always
• A random field estimate
• The service panel rating

NEC Reference: NEC 430.6(A)(1)

Question 26: Every generator must be provided with a nameplate giving the manufacturer's name, rated frequency, power factor, number of phases (if AC), and:

• Rated voltage, amperes, and kW or kVA
• The installer's name only
• No nameplate is required
• Only the purchase date

NEC Reference: NEC 445.11

Question 27: Dry-type transformers rated 600 volts or less generally must have adequate ventilation and be installed such that the ventilating openings are:

• Not obstructed by walls or nearby materials
• Always sealed shut
• Painted over
• It does not matter

NEC Reference: NEC 450.9

Question 28: In Class I hazardous locations, atmospheric gas or vapor mixtures are subdivided by material group into which of the following?

• Groups A, B, C, and D
• Groups 1, 2, and 3 only
• Groups E, F, and G only
• There is no subdivision

NEC Reference: NEC 500.6(A)

Question 29: Under the small conductor rule, 18 AWG copper conductors are limited to a maximum standard overcurrent device rating of:

• 7 amperes
• 15 amperes
• 20 amperes
• 30 amperes

NEC Reference: NEC 240.4(D)(1)

Question 30: A single means of disconnecting all ungrounded main power supply conductors must be provided for each elevator, escalator, or moving walk. This disconnect must be:

• Within sight of the motor controller
• Located anywhere in the building
• Not required if a fuse is used
• Located only in the basement

NEC Reference: NEC 620.51