Practice Test Geeks(NECA) National Electrical Contractors Association Practice Test
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Electrical Systems & Equipment Flashcards

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

Read the first 7 Electrical Systems & Equipment flashcards as text

  1. What is the maximum voltage drop allowed by the NEC for branch circuits as a recommendation?

    Answer: 3%

    The NEC recommends a maximum 3% voltage drop on branch circuits for optimal efficiency.

  2. Which type of transformer connection is most commonly used to supply three-phase power to commercial buildings in the US?

    Answer: Delta-Wye

    Delta-Wye transformers are standard for commercial applications because the Wye secondary provides a neutral for 120V single-phase loads.

  3. A 480V, 3-phase motor draws 40A at full load. What is the approximate kVA demand?

    Answer: 33.3 kVA

    kVA = V × A × √3 / 1000 = 480 × 40 × 1.732 / 1000 ≈ 33.3 kVA.

  4. Which device automatically disconnects a circuit when it detects an arc fault condition?

    Answer: AFCI breaker

    An Arc Fault Circuit Interrupter (AFCI) detects dangerous arc faults and opens the circuit to prevent fires.

  5. What does the 'interrupting rating' of a circuit breaker indicate?

    Answer: Maximum fault current it can safely clear

    The interrupting rating specifies the maximum short-circuit current the breaker can safely interrupt without damage.

  6. In an electrical panel, what is the purpose of a main bonding jumper?

    Answer: Connects the neutral bar to the equipment grounding conductor

    The main bonding jumper connects the grounded (neutral) conductor to the equipment grounding conductor and enclosure at the service entrance.

  7. What is the standard frequency of alternating current in the United States?

    Answer: 60 Hz

    The US uses 60 Hz AC power, while most of Europe and Asia use 50 Hz.