NEC 2020 Code Questions Practice Test 3

Question 1: What is ampacity of 1/0 THWN conductor in a dry location at an ambient temperature of 104⁰ F if the raceway contains four 1/0 THWN conductors?

• 132
• 124
• 165
• 170

NEC Reference: NEC 310.15(B)(16)

Question 2: What size conductor are required for a single family dwelling unit with a calculated load of 220 Amperes and the maximum unbalanced neutral load is 110 amperes?

• 1/0 AWG and 4 AWG
• 3/0 AWG and 3 AWG
• 3/0 AWG and 2 AWG
• 2/0 AWG and 2 AWG

NEC Reference: NEC 310.15(B)(7)

Question 3: What is the minimum size of copper conductor used for surge protective devices?

• 14 AWG
• 12 AWG
• 10 AWG
• 8 AWG

NEC Reference: NEC 242.62

Question 4: If storage batteries are used as emergency power systems. what is the minimum time that they should supply emergency loads?

• 1 1/2 hours
• 1 hour
• 1/2 hour
• 2 hours

NEC Reference: NEC 700.12

Question 5: In a wet location, the enclosure shall be mounted that there is at least ................... airspace between enclosure and the wall.

• 1/4 inch
• 1/2 inch
• 3/4 inch
• 1 inch

NEC Reference: NEC 312.2

Question 6: The low voltage lighting system transformer has a power rating of 300 watts at 15 volts. How many 25 watts lams can be connected in the lighting system?

• 12
• 10
• 15
• 11

Question 7: The building entry points of underground ducts or conduits must be sealed.

• False
• True

NEC Reference: NEC 230.8

Question 8: What is the demand factor in percentage for a non-dwelling unit with a receptacle load of 15 kVA?

• 50 %
• 75 %
• 90 %
• 82 %

NEC Reference: NEC 220.44

Question 9: The computed branch circuit load should not be less than which of the following percentage of continuous load in the circuit?

• 100 %
• 125 %
• 115 %
• 150 %

Question 10: Receptacles installed on 20 ampere branch circuit shall not be of grounding type.

• True
• False

Question 11: An AC system supplying premises wiring, operating between 50 and 1000 volts, must be grounded if the system can be so grounded that the maximum voltage to ground does not exceed:

• 120 volts
• 150 volts
• 208 volts
• 300 volts

NEC Reference: NEC 250.20(B)

Question 12: As a general rule, how many services are permitted to supply a single building or structure?

• Only one
• Exactly two, always
• As many as the owner wants
• No limit is specified

NEC Reference: NEC 230.2

Question 13: All 125 volt, 15 and 20 ampere receptacles installed in a dwelling unit laundry area require:

• GFCI protection
• AFCI protection only
• No special protection
• A dedicated 50 ampere circuit

NEC Reference: NEC 210.8(A)(7)

Question 14: A dwelling unit kitchen must be supplied by a minimum of how many 20 ampere small-appliance branch circuits?

• One
• Two
• Three
• Four

NEC Reference: NEC 210.11(C)(1)

Question 15: The 20 ampere small-appliance branch circuits serving kitchen countertop receptacles shall not supply which of the following?

• Outlets outside the kitchen/dining areas, such as lighting outlets
• Additional kitchen countertop receptacles
• The dining room receptacles
• The refrigerator receptacle

NEC Reference: NEC 210.52(B)(1)

Question 16: Overhead service conductors must maintain a minimum vertical clearance above a roof surface of:

• 3 feet
• 8 feet
• 12 feet
• 18 feet

NEC Reference: NEC 230.24(A)

Question 17: Interior metal water piping installed in or attached to a building must be bonded to which of the following?

• The service equipment or grounding electrode system
• The water utility meter only, and nothing else
• It never needs to be bonded
• Only the hot water heater

NEC Reference: NEC 250.104(A)

Question 18: Raceways are generally prohibited from being used as a means of support for other:

• Raceways, cables, or non-electrical equipment
• Nothing — this is always permitted
• Only lighting fixtures
• Only fire alarm cable

NEC Reference: NEC 300.11(B)

Question 19: Conductors are permitted to be connected in parallel (electrically joined at both ends) only when they are sized:

• 1/0 AWG and larger
• 14 AWG and larger
• 8 AWG and larger
• Any size is permitted to be paralleled

NEC Reference: NEC 310.10(H)(1)

Question 20: Where NM cable is installed through a hole in a metal framing member, what protection must be provided?

• A listed bushing or grommet
• Electrical tape wrapped around the cable
• No protection is required
• A wood spacer only

NEC Reference: NEC 300.4(B)(1)

Question 21: In general, a switch enclosure must have provisions for connecting an equipment grounding conductor, and the box containing the switch must also have available:

• A grounded (neutral) conductor
• A second hot conductor only
• Nothing additional is ever required
• A 240 volt circuit only

NEC Reference: NEC 404.2(C)

Question 22: A recessed luminaire that is NOT identified as Type IC (insulation contact) must maintain a minimum clearance from thermal insulation of:

• 1 inch
• 3 inches
• 6 inches
• 12 inches

NEC Reference: NEC 410.116(B)

Question 23: Every fixed or stationary appliance must be provided with a means to disconnect it from all ungrounded conductors. Which of the following can serve as that disconnecting means?

• A branch-circuit switch, breaker, or attachment plug
• The appliance nameplate alone
• No disconnecting means is ever required
• Only a fused disconnect switch

NEC Reference: NEC 422.30

Question 24: Fixed electric heating cable installed in a bathroom or similar area, embedded in a floor, must be protected by:

• GFCI protection
• A fusible link only
• No special protection
• A separate disconnect switch only

NEC Reference: NEC 424.44(G)

Question 25: Per NEC Table 430.52, for an inverse time circuit breaker protecting a general (non-design-letter) squirrel-cage motor, the maximum standard setting is what percentage of motor full-load current?

• 150 %
• 175 %
• 250 %
• 400 %

NEC Reference: NEC Table 430.52

Question 26: An individual disconnecting means for a motor and its associated equipment must be located within sight from the controller location, meaning within:

• 25 feet
• 50 feet
• 75 feet
• 100 feet

NEC Reference: NEC 430.102(B)

Question 27: A cord-and-plug-connected room air conditioner must be:

• Grounded
• Double insulated only, never grounded
• Ungrounded is acceptable
• Bonded to gas piping only

NEC Reference: NEC 440.61

Question 28: Boxes and enclosures for emergency circuits must be permanently marked so they are recognized as a component of an emergency circuit. What color is commonly specified for this identification?

• Orange
• Blue
• White
• Black

NEC Reference: NEC 700.10(B)

Question 29: Central heating equipment other than fixed electric space-heating equipment must be supplied by:

• An individual branch circuit
• The kitchen small-appliance circuit
• Any general-purpose lighting circuit
• A shared circuit with the water heater

NEC Reference: NEC 422.12

Question 30: Every circuit and circuit modification at a panelboard must be legibly identified as to its clear, evident, and specific purpose on:

• A circuit directory at the panelboard
• Nothing — labeling is optional
• A note left with the homeowner only
• The utility bill

NEC Reference: NEC 408.4(A)