CEA NEC Code and Calculations 5 — Questions and Answers
Question 1: Under NEC 210.52, receptacle outlets in a dwelling unit kitchen must be served by at least how many small appliance branch circuits?
- Two 20-ampere circuits (Correct answer)
- One 20-ampere circuit
- Three 15-ampere circuits
- One 15-ampere circuit
Correct answer: Two 20-ampere circuits
NEC 210.52(B)(1) requires at least two 20-ampere small appliance branch circuits for kitchen receptacle outlets.
Question 2: According to the NEC, what is the minimum cover depth for direct-buried Type UF cable under a public sidewalk?
- 24 inches (Correct answer)
- 12 inches
- 6 inches
- 18 inches
Correct answer: 24 inches
NEC Table 300.5 requires Type UF cable to be buried at least 24 inches under a public sidewalk or driveway.
Question 3: What is the kVA demand for three household ranges each rated at 12 kW, using NEC Table 220.55?
- 21 kW (Correct answer)
- 36 kW
- 12 kW
- 26 kW
Correct answer: 21 kW
NEC Table 220.55 specifies a demand of 21 kW (maximum demand) for three ranges each rated between 8.75–12 kW using Column C values.
Question 4: The NEC defines a 'qualified person' as someone who has skills and knowledge related to the construction and operation of the electrical equipment and has received which type of training?
- Safety training on the hazards involved (Correct answer)
- A state electrical license
- A four-year apprenticeship certificate
- An OSHA 30-hour card
Correct answer: Safety training on the hazards involved
NEC Article 100 defines a qualified person as one who has skills, knowledge of electrical equipment, and has received safety training on the hazards involved.
Question 5: Under NEC 250.52, which of the following qualifies as a grounding electrode?
- A metal underground water pipe in contact with the earth for at least 10 feet (Correct answer)
- A plastic water pipe buried 6 feet deep
- A copper wire tied to a rebar in a concrete slab above grade
- A galvanized steel fence post driven 4 feet into the earth
Correct answer: A metal underground water pipe in contact with the earth for at least 10 feet
NEC 250.52(A)(1) permits a metal underground water pipe with at least 10 feet of direct contact with the earth as a grounding electrode.
Question 6: According to the NEC, what is the maximum distance between supports for EMT (electrical metallic tubing) installed horizontally?
- 10 feet (Correct answer)
- 6 feet
- 8 feet
- 12 feet
Correct answer: 10 feet
NEC 358.30 requires EMT to be securely fastened at intervals not exceeding 10 feet.
Question 7: A panelboard feeder must be sized for the calculated load plus a demand factor. If the calculated load is 120 amperes continuous, what is the minimum feeder conductor ampacity?
- 150 amperes (Correct answer)
- 120 amperes
- 144 amperes
- 125 amperes
Correct answer: 150 amperes
NEC 215.2(A)(1) requires feeder conductors for continuous loads to be sized at 125% of the continuous load: 120A × 1.25 = 150 amperes.
CEA NEC Code and Calculations 5
Under NEC 210.52, receptacle outlets in a dwelling unit kitchen must be served by at least how many small appliance branch circuits?