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NEC CODE NEC 2023

Single family dwelling unit Practice Questions

NEC Code Questions : Single family dwelling unit calculations

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Frequently Asked Questions

Yes — free, no signup required. Each question links to the relevant NEC article so you can study the code directly.

The National Electrical Code (NFPA 70) is the benchmark standard for safe electrical installation in the US. It is updated every 3 years by the NFPA.

Study the edition adopted by your state. As of 2025, most states use the 2020 or 2023 NEC. These tests are written to the 2023 edition.

The most tested articles are 100 (Definitions), 200–250 (Wiring & Grounding), 300–314 (Wiring Methods), 400–411 (Conductors), 430 (Motors), and 700–701 (Emergency Systems).

How to Use This Practice Test

This Single family dwelling unit Practice Questions has 9 questions with detailed answers and NEC references. Take the full test, review every wrong answer, and look up the NEC article it references before moving on.

Tip: Use the NEC index (back of the book) — find answers by keyword, not by article number.

Topics covered: NEC articles 100, 210, 220, 240, 250, 300, 310, 430, and special occupancies.
Passing score: Aim for 80%+ on NEC code tests before exam day.
Questions: 9 multiple-choice, one correct answer each

9

Questions

14 min

Time

70%

Pass

Timer starts immediately. Progress is auto-saved.

Single family dwelling unit Practice Questions — Question List

Question 1: What is the minimum feeder or service load for cloth dryers in a dwelling unit?

5000 watts
2500 watts
4000 watts
6500 watts

NEC Reference: NEC 220.54

Question 2: If a single family unit consists of one air conditioner rated at 3 kW and fixed heating equipment rated at 2.5 kw? What is the total dwelling calculated load for both?

3 kW
2.5 kW
5.5 kW
1.5 kW

NEC Reference: NEC 220.60

Question 3: Service conductors supplying the entire one dwelling unit load can have an ampacity of .............. percentage the service rating.

83
75
95
80

NEC Reference: NEC 310.15(B)(7)

Question 4: As per NEC what is the minimum general lighting load that is used for branch circuit and feeder/Service calculations of a single family dwelling unit?

3 Volt-ampere per square foot
2 Volt-ampere per square foot
1 Volt-ampere per square foot
4 Volt-ampere per square foot

NEC Reference: NEC 220.12

Question 5: In a single family dwelling unit when four or more appliances are fastened in a place and connected to the same feeder then ....................... percentage demand can be applied in calculating total demand load.

75
85
83
90

Question 6: What is the minimum general lightening load required for 1500 square foot single family house as permissible by NEC?

4500 VA
4800 VA
3000 VA
1500 VA

Question 7: Which of the following lamp holders are used in 15 ampere branch circuit that is used to supply fixed lightening units in dwelling unit?

standard duty lampholders
heavy duty lamp holders
both standard and heavy duty lamp holders

Question 8: All 15 or 20 ampere receptacle outlets installed in bathrooms of dwelling unit must always require ...........................

non ground receptacles
water proof receptacles
Ground fault circuit interceptor ( GFCI)
protective gaurd

NEC Reference: NEC 210.8(A)(1)

Question 9: for single family dwelling unit what is the minimum allowable rating of a 3 wire service entrance conductor?

125 amperes
100 amperes
150 amperes
175 amperes

NEC Reference: NEC 230.42(B)

Key NEC References for This Test

Article	What It Covers
Ch. 1–4	General rules — apply to all installations
Ch. 5–7	Special rules — override Ch. 1–4 where they conflict
Ch. 8	Communications — completely independent of Ch. 1–7
Ch. 9	Tables — referenced by articles, not standalone enforceable rules
Art. 210.12	AFCI — major expansion in NEC 2026
Art. 230.67	Surge protection at service equipment — new NEC 2026

Study Tip: Learn the NEC index — use keywords, not article numbers. Practice finding 5 different topics in under 2 minutes each.

EXAM CARD NEC CODE

Questions9

Time limit14 min

Pass score70%

Code editionNEC 2023

DifficultyIntermediate

Last reviewedJun 2026

Timer starts immediately. Progress is auto-saved.

Source: NEC 2026 (NFPA 70)