Questions and Answers
How many first-level subdivisions exist in Section 250.122?
7
A conductor with continuous white or gray covering shall be used only for the grounded circuit conductor.
True
A supplementary grounding electrode is required when the only grounding electrode available is?
a metal underground water pipe
Match the article title with the appropriate NEC article.
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Which list items does Exception No. 1 in Section 210.8(B) apply to?
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The broad scope of Chapter 2, Wiring and Protection, is addressed by subdividing this chapter into how many articles?
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The definition of tap conductors is located in which section?
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What is defined as the circuit conductors between the final overcurrent device and the outlet(s)?
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What is defined as an area including a sink with plumbing fixtures?
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An 8 AWG gray insulated neutral conductor is acceptable to supply a 120-volt electrical heater.
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General-purpose branch circuits rated at 30 amperes are acceptable for lighting and receptacle circuits in dwelling units.
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One common neutral conductor is acceptable with two sets of 120/208-volt feeders.
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In a strip mall, service conductors for Building No. 2 can pass through Building No. 1.
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What is the minimum overhead clearance for branch-circuit conductors crossing a sidewalk?
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What is the maximum nominal voltage permitted for a luminaire installed in a motel room?
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The required branch-circuit overcurrent protection rating for a continuous load of 80 amperes is 100 amperes.
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What is the minimum calculated feeder load for 12 feet of show window lighting?
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What should circuit breakers used for switching fluorescent lighting circuits be marked?
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What is the feeder load for each small-appliance branch circuit required in a dwelling unit?
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How far shall service-entrance cables be supported from the service head?
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What is the minimum length for a rod-type grounding electrode?
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What is the minimum vertical clearance for overhead service drop conductors from roofs?
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Surge-protective devices (SPDs) must be installed indoors and accessible to unqualified persons.
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The NEC requires a conductor to have overcurrent protection at the point it receives its supply.
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Where shall Type 2 SPDs be connected in relation to a service disconnect overcurrent device?
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Study Notes
NEC Chapter 2: Planning the Installation
- Section 250.122 contains 7 first-level subdivisions.
- Continuous white or gray covering on conductors is reserved for the grounded circuit conductor (200.7).
- A supplementary grounding electrode is mandatory when the only available one is a metal underground water pipe (250.53).
- Articles associated with various topics:
- Branch Circuits → Article 210
- Branch-Circuit, Feeder, and Service Load Calculations → Article 220
- Feeders → Article 215
- Overvoltage Protection → Article 242
- Outside Branch Circuits and Feeders → Article 225
- Grounding and Bonding → Article 250
- Use and Identification of Grounded Conductors → Article 200
- Services → Article 230
- Overcurrent Protection → Article 240
- Exception No. 1 in subdivision 210.8(B) applies only to list items (3) and (4).
- Chapter 2, Wiring and Protection, includes a total of 9 articles.
- Article 240 details the general location provisions for overcurrent protective devices and defines tap conductors in Section 240.2.
- A branch circuit refers to conductors between the final overcurrent device and the outlet(s) (100).
- A bathroom is defined as an area with a sink and one or more plumbing fixtures, such as a toilet or a shower (100).
- An 8 AWG gray insulated neutral conductor is allowed for a 120-volt heater (200.6(A)).
- Installing general-purpose branch circuits rated at 30 amperes for lighting and receptacles in dwelling units is a violation (210.23(B)).
- A common neutral conductor with two sets of 120/208-volt, 3-phase, 4-wire feeders is acceptable (215.4(A)).
- Service conductors passing through the interior ceiling space of adjacent buildings is a violation (230.3).
- Overhead branch-circuit conductors must maintain a minimum clearance of 10 feet when crossing sidewalks (225.18(1)).
- The maximum nominal voltage for luminaires in motel rooms is limited to 120V (210.6(A)(1)).
- Continuous loads of 80 amperes require branch-circuit overcurrent protection rated at 100 amperes (210.20(A)).
- For 12 feet of show window lighting, the minimum calculated feeder load is 2,400 VA (220.43(A)).
- Circuit breakers for fluorescent lighting circuits must be marked as HID or SWD (240.83(D)).
- The feeder load for each small-appliance branch circuit in a dwelling unit is calculated at 1,500 VA (220.52(A)).
- Service-entrance cables must be supported within 12 inches of the service head (230.51(A)).
- A rod-type grounding electrode must be at least 8 feet long (250.52(A)(5)).
- Overhead service drop conductors require a vertical clearance of at least 8 feet from roofs (230.24(A)).
- Surge-protective devices (SPDs) can be installed indoors or outdoors and should be accessible unless listed otherwise (242.22).
- NEC mandates that conductors have overcurrent protection where they receive their supply (240.21).
- Type 2 SPDs must be connected on the load side of the service disconnect overcurrent device as outlined in Section 230.91 (242.14(A)).
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Test your knowledge on the National Electrical Code (NEC) Chapter 2 with these flashcards. Each card covers key concepts related to planning the installation according to NEC standards, including important definitions and requirements. Perfect for electrical professionals preparing for installation tasks.
