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NEC CODE NEC 2023

Service Entrance, Branch Circuits & Feeder Conductors 2 — NEC 2023 Edition

Free NEC 2023 practice test on service entrance, feeders, and branch circuits. Covers feeder ampacity sizing, dwelling and commercial lighting load demand, receptacle load calculations, service disconnect rules, and unbalanced load. Simple English, full explanations.

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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).

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This Service Entrance, Branch Circuits & Feeder Conductors 2 — NEC 2023 Edition has 30 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: 30 multiple-choice, one correct answer each

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Service Entrance, Branch Circuits & Feeder Conductors 2 — NEC 2023 Edition — Question List

Question 1: Two transformers, each rated 480 VA, are connected to a single 120-volt feeder, along with one utilization equipment rated 80 VA. What is the minimum feeder ampere rating?

9 amperes
10 amperes
12 amperes
7 amperes

NEC Reference: NEC 215.2(A)(1)

Question 2: A dwelling unit has a general lighting connected load of 4,000 VA. What is the total demand load after applying the lighting demand factor?

3,350 VA
4,000 VA
3,200 VA
3,600 VA

NEC Reference: NEC Table 220.45

Question 3: What is the branch-circuit load calculated for a show window that is 10 feet wide (measured horizontally along its base)?

2,000 VA
1,800 VA
1,600 VA
2,200 VA

NEC Reference: NEC 220.14(G)

Question 4: How many 15-ampere, 14 AWG branch circuits are minimally required to supply the general lighting load for a 2,000 sq ft dwelling unit at 120 volts?

NEC Reference: NEC Table 220.42 / 210.11

Question 5: A retail shop has 20 duplex receptacles, each on its own yoke. What is the calculated load for these receptacles?

300 volt-amperes
3,600 volt-amperes
1,800 volt-amperes
36,000 volt-amperes

NEC Reference: NEC 220.14(I)

Question 6: In a shopping complex, what is the maximum number of receptacles generally permitted on a 20-ampere, 120-volt breaker, using the standard 180 VA per receptacle?

NEC Reference: NEC 220.14(I)

Question 7: A single piece of equipment has five receptacles built into it. What is the total calculated load for these receptacles?

450 volt-amperes
900 volt-amperes
600 volt-amperes
800 volt-amperes

NEC Reference: NEC 220.14(I)

Question 8: How many 15-ampere, 2-wire branch circuits are needed for the general lighting load of a 120/240-volt, 1,200 sq ft dwelling unit?

NEC Reference: NEC Table 220.42

Question 9: What is the minimum laundry circuit load that must be considered for each 2-wire laundry branch circuit in a dwelling unit?

1,500 Volt-Amperes
1,200 Volt-Amperes
1,000 Volt-Amperes
800 Volt-Amperes

NEC Reference: NEC 220.52(B)

Question 10: True or false: the maximum unbalanced load of a service or feeder is the maximum net calculated load between the hot conductor and the neutral conductor.

True
False
Only for 3-phase feeders
Only for services under 100A

NEC Reference: NEC 220.61

Question 11: For a one-family dwelling, what is the maximum number of service disconnects generally permitted, grouped at one location?

6
2
10
There is no limit

NEC Reference: NEC 230.71(A)

Question 12: For a one-family dwelling, what is the minimum rating required for the service disconnecting means?

100 amperes
60 amperes
125 amperes
200 amperes

NEC Reference: NEC 230.79(C)

Question 13: Overhead service conductors above a roof generally need a vertical clearance of at least how much?

8 feet
3 feet
15 feet
25 feet

NEC Reference: NEC 230.24(A)

Question 14: A service mast used to support service-drop conductors must generally be what?

Strong enough for the strain
Made of any weak material
Left unsupported
Optional to install

NEC Reference: NEC 230.28

Question 15: Feeder conductors must generally be protected against overcurrent according to what?

Ampacity
Color
Length only
Manufacturer preference

NEC Reference: NEC 215.3

Question 16: Per the NEC informational note, what is the recommended maximum COMBINED voltage drop for a feeder plus branch circuit together?

NEC Reference: NEC 215.2(A) Informational Note

Question 17: Service entrance cable exposed to physical damage must generally be protected by what?

Rigid conduit
Tape only
Nothing at all
Paint

NEC Reference: NEC 230.50(A)

Question 18: Each service disconnect must be marked to show what?

Its ampere rating
The installer's name
Nothing at all
The paint color

NEC Reference: NEC 230.79

Question 19: A service disconnect must be located where?

A readily accessible location
Attic only
Locked closet with no key
Crawlspace only

NEC Reference: NEC 230.70(A)(1)

Question 20: For a grounded system, a connection to the grounding electrode system must be made at what point?

The service
A random branch circuit
The neighbor's panel
Nowhere is required

NEC Reference: NEC 250.24(A)

Question 21: Under the 10-foot feeder tap rule, tap conductors not over 10 feet long must have an ampacity of not less than what?

The load served or terminating device rating
Any size at all
Half the feeder size
A fixed 15 amperes

NEC Reference: NEC 240.21(B)(1)

Question 22: In a building with multiple occupancies, each occupancy must generally have what, per feeder and service disconnect access rules?

Access to their own disconnect, or supervised building management
No access is ever needed
A single shared key given to no one
Nothing is required

NEC Reference: NEC 230.72(C)

Question 23: Per NEC 230.42(B), ungrounded service-entrance conductors for a specific installation generally must not be smaller than what, relative to the service disconnecting means?

The rating of the service disconnecting means
Any size, chosen at random
Half the disconnect rating
Twice the disconnect rating

NEC Reference: NEC 230.42(B)

Question 24: When calculating a feeder or service load using the standard method, what is generally done after finding the general lighting connected load?

Apply the general lighting demand factor
Call the building inspector
Skip straight to the service disconnect size
Ignore the lighting load entirely

NEC Reference: NEC Table 220.45

Question 25: For service equipment rated 0-150 volts to ground under Condition 1, what is the minimum required clear working space depth?

3 feet
1 foot
6 feet
10 feet

NEC Reference: NEC Table 110.26(A)(1)

Question 26: For a single dwelling unit, the "optional" feeder or service load calculation method can be used instead of the standard method under which condition?

Single 120/240V or 208Y/120V service, 100A or more
Only for buildings with 3-phase power
Only for services under 60 amperes
It can never be used for dwellings

NEC Reference: NEC 220.82

Question 27: Raceways entering a building from an underground service must generally be what, to keep moisture out?

Sealed with an approved material
Left completely open
Filled with sand only
Nothing is required

NEC Reference: NEC 230.8

Question 28: Service equipment must have a rating not less than what, per NEC 230.79?

The calculated load to be carried
A random guess
The physical size of the meter
Nothing -- any rating works

NEC Reference: NEC 230.79

Question 29: In a two-family dwelling with individually metered units, each unit's feeder is generally sized based on what?

That individual unit's own calculated load
The whole building's load, divided randomly
A flat, unrelated fixed value
Nothing -- feeders do not need sizing

NEC Reference: NEC Article 220

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.

Service Entrance, Branch Circuits & Feeder Conductors 2 — NEC 2023 Edition

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Service Entrance, Branch Circuits & Feeder Conductors 2 — NEC 2023 Edition

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Service Entrance, Branch Circuits & Feeder Conductors 2 — NEC 2023 Edition — Question List

Question 1: Two transformers, each rated 480 VA, are connected to a single 120-volt feeder, along with one utilization equipment rated 80 VA. What is the minimum feeder ampere rating?

Question 2: A dwelling unit has a general lighting connected load of 4,000 VA. What is the total demand load after applying the lighting demand factor?

Question 3: What is the branch-circuit load calculated for a show window that is 10 feet wide (measured horizontally along its base)?

Question 4: How many 15-ampere, 14 AWG branch circuits are minimally required to supply the general lighting load for a 2,000 sq ft dwelling unit at 120 volts?

Question 5: A retail shop has 20 duplex receptacles, each on its own yoke. What is the calculated load for these receptacles?

Question 6: In a shopping complex, what is the maximum number of receptacles generally permitted on a 20-ampere, 120-volt breaker, using the standard 180 VA per receptacle?

Question 7: A single piece of equipment has five receptacles built into it. What is the total calculated load for these receptacles?

Question 8: How many 15-ampere, 2-wire branch circuits are needed for the general lighting load of a 120/240-volt, 1,200 sq ft dwelling unit?

Question 9: What is the minimum laundry circuit load that must be considered for each 2-wire laundry branch circuit in a dwelling unit?

Question 10: True or false: the maximum unbalanced load of a service or feeder is the maximum net calculated load between the hot conductor and the neutral conductor.

Question 11: For a one-family dwelling, what is the maximum number of service disconnects generally permitted, grouped at one location?

Question 12: For a one-family dwelling, what is the minimum rating required for the service disconnecting means?

Question 13: Overhead service conductors above a roof generally need a vertical clearance of at least how much?

Question 14: A service mast used to support service-drop conductors must generally be what?

Question 15: Feeder conductors must generally be protected against overcurrent according to what?

Question 16: Per the NEC informational note, what is the recommended maximum COMBINED voltage drop for a feeder plus branch circuit together?

Question 17: Service entrance cable exposed to physical damage must generally be protected by what?

Question 18: Each service disconnect must be marked to show what?

Question 19: A service disconnect must be located where?

Question 20: For a grounded system, a connection to the grounding electrode system must be made at what point?

Question 21: Under the 10-foot feeder tap rule, tap conductors not over 10 feet long must have an ampacity of not less than what?

Question 22: In a building with multiple occupancies, each occupancy must generally have what, per feeder and service disconnect access rules?

Question 23: Per NEC 230.42(B), ungrounded service-entrance conductors for a specific installation generally must not be smaller than what, relative to the service disconnecting means?

Question 24: When calculating a feeder or service load using the standard method, what is generally done after finding the general lighting connected load?

Question 25: For service equipment rated 0-150 volts to ground under Condition 1, what is the minimum required clear working space depth?

Question 26: For a single dwelling unit, the "optional" feeder or service load calculation method can be used instead of the standard method under which condition?

Question 27: Raceways entering a building from an underground service must generally be what, to keep moisture out?

Question 28: Service equipment must have a rating not less than what, per NEC 230.79?

Question 29: In a two-family dwelling with individually metered units, each unit's feeder is generally sized based on what?

Key NEC References for This Test

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