Practice Test GeeksIEC - Independent Electrical Contractors Practice Test
← All IEC Flashcard Decks

Conductors and Branch Circuits Flashcards

7 cards from real IEC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Conductors and Branch Circuits flashcards as text

  1. A branch circuit overcurrent device is rated 20 amperes. The connected load includes a single motor with a full-load current of 16 amperes. Does this comply with NEC branch circuit rules?

    Answer: No, motor branch circuits must be sized at 125% of FLC per NEC 430.22

    NEC Section 430.22 requires motor branch circuit conductors to be sized at not less than 125% of the motor's full-load current, so 16A × 1.25 = 20A minimum conductor ampacity.

  2. When is it permissible to use 10 AWG copper on a 30-ampere branch circuit per NEC Article 210?

    Answer: When the circuit supplies a single receptacle rated 30 amperes

    NEC Section 210.21(B) permits a single 30-ampere receptacle outlet to be supplied by 10 AWG copper (30A at 75°C) on a 30-ampere branch circuit.

  3. Which insulation type is listed for use in wet locations as well as dry locations, making it suitable for outdoor branch circuit wiring in conduit?

    Answer: THWN

    THWN (Thermoplastic, Heat- and Moisture-Resistant, Nylon-jacketed) insulation is listed for both wet and dry locations and is commonly used in outdoor conduit runs.

  4. Where two or more branch circuits supply devices in the same enclosure, what color coding must the grounded (neutral) conductors follow per NEC 200.6?

    Answer: Neutrals must be identified by white or gray color, or three white stripes on another color

    NEC Section 200.6 requires grounded conductors to be identified by a continuous white or gray outer finish, or three continuous white or gray stripes on other than green insulation.

  5. In a dwelling unit, how many small-appliance branch circuits are required by NEC 210.11(C)(1) for kitchen, pantry, breakfast room, and dining room receptacles?

    Answer: At least two 20-ampere small-appliance branch circuits

    NEC Section 210.11(C)(1) mandates a minimum of two 20-ampere small-appliance branch circuits for receptacles in the kitchen, pantry, breakfast room, and dining room.

  6. What is the effect of raising the ambient temperature above 30°C (86°F) on a conductor's allowable ampacity?

    Answer: Ampacity must be derated using the correction factors in NEC Table 310.15(B)(1)

    Higher ambient temperatures reduce a conductor's ability to dissipate heat, requiring a correction factor from NEC Table 310.15(B)(1) to derate the allowable ampacity.

  7. A branch circuit runs 150 feet from the panelboard to a 120V, 10-ampere load. Which NEC guideline addresses keeping voltage drop within acceptable limits?

    Answer: NEC 210.19(A) Informational Note recommends voltage drop not exceed 3% on branch circuits

    NEC Section 210.19(A) contains an Informational Note recommending that voltage drop on branch circuits not exceed 3% to maintain efficiency and equipment performance.