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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. What is the minimum branch circuit rating permitted for a single outlet on a household appliance circuit where the appliance nameplate rating is 12 amperes?

    Answer: 15 amperes

    A 15-ampere branch circuit is sufficient when the single outlet serves an appliance rated at 12 amperes, since 12A does not exceed 80% of 15A for continuous loads.

  2. Which NEC table is used to determine the allowable ampacity of conductors in conduit based on temperature rating and insulation type?

    Answer: Table 310.16

    NEC Table 310.16 lists the allowable ampacities of insulated conductors rated up to 2000V in raceway, cable, or earth.

  3. A 20-ampere, 120-volt branch circuit supplies multiple receptacle outlets. What is the maximum load that may be connected continuously?

    Answer: 16 amperes

    Continuous loads on a branch circuit must not exceed 80% of the circuit rating, so 80% of 20A = 16 amperes.

  4. What gauge is the smallest copper conductor permitted for branch circuits under NEC Article 210?

    Answer: 14 AWG

    NEC Section 210.19 permits 14 AWG copper as the minimum conductor size for branch circuits, which corresponds to a 15-ampere rating.

  5. When conductors of different circuits are installed in the same raceway, which NEC adjustment factor must be applied?

    Answer: Bundling or fill derating factor

    When more than three current-carrying conductors are in a raceway, NEC Table 310.15(C)(1) bundling derating factors must be applied to reduce allowable ampacity.

  6. Under the NEC, what is the maximum voltage permitted between conductors on a branch circuit supplying luminaires in a dwelling unit?

    Answer: 150 volts

    NEC Section 210.6 limits branch circuits supplying luminaires in dwelling units to a maximum of 150 volts to ground.

  7. What is the purpose of a neutral conductor on a multiwire branch circuit?

    Answer: It carries the unbalanced load current and completes the circuit

    The neutral on a multiwire branch circuit carries the difference (unbalanced) current between the two hot conductors and completes the return path.