NEC 2020 Code Questions Practice Test 19

Question 1: A dwelling has 2000 square feet. Using 3 VA per square foot, what is the general lighting load?

• 3000 VA
• 6000 VA
• 9000 VA
• 12000 VA

NEC Reference: NEC Table 220.12

Question 2: A dwelling has a general lighting load of 4000 VA. The first 3000 VA is at 100%, and the rest at 35%. What is the demand load?

• 3000 VA
• 3350 VA
• 3600 VA
• 4000 VA

NEC Reference: NEC Table 220.42

Question 3: A dwelling has 2 small appliance circuits and 1 laundry circuit, each at 1500 VA. What is the total load?

• 3000 VA
• 4500 VA
• 6000 VA
• 1500 VA

NEC Reference: NEC 220.52

Question 4: A one-family dwelling service is rated 200 amperes. Using the 83% rule, what minimum ampacity is needed for the service conductors?

• 150 amperes
• 166 amperes
• 180 amperes
• 200 amperes

NEC Reference: NEC 310.12

Question 5: What is the ampacity of a 2 AWG copper THWN conductor in a dry location, per the 75 C column?

• 95 amperes
• 115 amperes
• 130 amperes
• 150 amperes

NEC Reference: NEC Table 310.16

Question 6: What is the ampacity of a 4/0 AWG copper THWN conductor in a dry location, per the 75 C column?

• 195 amperes
• 230 amperes
• 260 amperes
• 310 amperes

NEC Reference: NEC Table 310.16

Question 7: A conductor rated 100 amperes at 30 C is used at an ambient of 40 C, where the correction factor is 0.88. What is the corrected ampacity?

• 80 amperes
• 88 amperes
• 94 amperes
• 100 amperes

NEC Reference: NEC Table 310.15(B)(1)

Question 8: A conductor rated 100 amperes is bundled with 5 others (6 total) in one raceway. The adjustment factor for 4-6 conductors is 80%. What is the adjusted ampacity?

• 70 amperes
• 80 amperes
• 90 amperes
• 100 amperes

NEC Reference: NEC Table 310.15(C)(1)

Question 9: Voltage drop in a circuit is found by multiplying the current by the:

• Circuit resistance
• Circuit color
• Number of outlets
• Building height

NEC Reference: NEC Chapter 9, Table 8

Question 10: The NEC informational note suggests a branch circuit alone should not have more than what voltage drop?

• 1 %
• 3 %
• 5 %
• 10 %

NEC Reference: NEC 210.19(A) Informational Note No. 4

Question 11: The recommended combined voltage drop for branch circuit plus feeder together is:

• 3 %
• 5 %
• 8 %
• 10 %

NEC Reference: NEC 215.2(A) Informational Note No. 2

Question 12: A 120 volt circuit has a resistance of 24 ohms. What is the current flow?

• 3 amperes
• 5 amperes
• 8 amperes
• 12 amperes

Question 13: A 240 volt circuit draws 10 amperes. What is the power in watts?

• 1200 watts
• 2400 watts
• 3600 watts
• 4800 watts

Question 14: A 480 volt, three-phase circuit draws 20 amperes. What is the approximate power, using 1.732 for the three-phase factor?

• 9600 watts
• 16,627 watts
• 24,000 watts
• 33,254 watts

Question 15: Two resistors of 10 ohms and 15 ohms are wired in series. What is the total resistance?

• 5 ohms
• 15 ohms
• 25 ohms
• 150 ohms

Question 16: For a single 2-wire branch circuit installation, the minimum service disconnect rating is:

• 15 amperes
• 30 amperes
• 60 amperes
• 100 amperes

NEC Reference: NEC 230.79(A)

Question 17: For installations not covered by the other specific rules, the minimum service disconnect rating is:

• 15 amperes
• 30 amperes
• 60 amperes
• 200 amperes

NEC Reference: NEC 230.79(D)

Question 18: The feeder neutral load is generally figured using the maximum unbalance between the neutral and:

• Any one ungrounded conductor
• Both ungrounded conductors combined
• The ground wire
• Total connected load, always

NEC Reference: NEC 220.61

Question 19: A home has heating and air conditioning that never run at the same time. For load calculations, you may:

• Omit the smaller load
• Add both loads fully
• Double the larger load
• Ignore both loads

NEC Reference: NEC 220.60

Question 20: A single dwelling clothes dryer is rated 4500 watts by the nameplate. What minimum load value is used?

• 4500 watts
• 5000 watts
• 5500 watts
• 4000 watts

NEC Reference: NEC 220.54

Question 21: A motor has a full-load current of 30 amperes. What is the minimum branch-circuit conductor ampacity?

• 30 amperes
• 37.5 amperes
• 45 amperes
• 60 amperes

NEC Reference: NEC 430.22(A)

Question 22: A continuous load draws 24 amperes. What is the minimum conductor ampacity needed?

• 24 amperes
• 30 amperes
• 36 amperes
• 48 amperes

NEC Reference: NEC 210.19(A)(1)

Question 23: An overcurrent device for a continuous load must be rated not less than what percent of that load?

• 100 %
• 125 %
• 150 %
• 200 %

NEC Reference: NEC 210.20(A)

Question 24: A single-phase 10 kVA transformer has a 240 volt primary. What is the approximate primary current?

• 24 amperes
• 32 amperes
• 41.7 amperes
• 50 amperes

Question 25: When more than 2 conductors are in a raceway, the maximum allowed fill is:

• 31 %
• 40 %
• 53 %
• 60 %

NEC Reference: NEC Chapter 9, Table 1

Question 26: A service has 4/0 AWG copper conductors. What is the minimum copper grounding electrode conductor size?

• 6 AWG
• 4 AWG
• 2 AWG
• 1/0 AWG

NEC Reference: NEC 250.66

Question 27: A circuit is protected by a 100 ampere breaker. What is the minimum copper equipment grounding conductor size?

• 10 AWG
• 8 AWG
• 6 AWG
• 4 AWG

NEC Reference: NEC 250.122

Question 28: A box has four 12 AWG conductors and one switch. Using 2.25 in3 per 12 AWG conductor, and the switch counted as two 12 AWG conductors, what is the total required box volume?

• 9 cubic inches
• 11.25 cubic inches
• 13.5 cubic inches
• 18 cubic inches

NEC Reference: NEC 314.16

Question 29: What is the ampacity of a 6 AWG copper THWN conductor in a dry location, per the 75 C column?

• 55 amperes
• 65 amperes
• 75 amperes
• 85 amperes

NEC Reference: NEC Table 310.16

Question 30: What is the ampacity of a 1/0 AWG copper THWN conductor in a dry location, per the 75 C column?

• 130 amperes
• 150 amperes
• 170 amperes
• 195 amperes

NEC Reference: NEC Table 310.16