Practice Test Geeks(E2) E2 Commercial Electrical Inspector Practice Test
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Overcurrent Protection Devices Flashcards

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  1. Per NEC 240.4(B), using the next higher standard overcurrent device rating above the conductor's calculated ampacity is NOT permitted when the conductor ampacity exceeds:

    Answer: 800 amperes

    NEC 240.4(B) prohibits rounding up to the next higher standard overcurrent device rating when the conductor ampacity exceeds 800 amperes; the OCPD must not exceed the conductor's ampacity.

  2. According to NEC 240.85, a circuit breaker with a straight voltage rating (e.g., 480V) is suitable for use in:

    Answer: Either solidly grounded or ungrounded systems at that voltage

    NEC 240.85 states that a straight voltage-rated circuit breaker may be applied in either solidly grounded or ungrounded systems at that voltage level.

  3. Per NEC Article 100, a current-limiting overcurrent protective device is defined as one that:

    Answer: Reduces the let-through current to a value less than the available fault current

    A current-limiting OCPD reduces the peak let-through current to a magnitude less than the maximum available fault current, reducing thermal and magnetic stress on protected equipment.

  4. Per NEC 240.24(E), in a multifamily dwelling, overcurrent devices protecting a specific dwelling unit shall be accessible to:

    Answer: The occupant of the dwelling unit that is protected

    NEC 240.24(E) requires that overcurrent devices protecting a dwelling unit be accessible to the occupant of that specific unit, allowing them to reset breakers without entering another tenant's space.

  5. Under NEC 110.9, equipment intended to interrupt current at fault levels must have an interrupting rating:

    Answer: Sufficient for the nominal circuit voltage and the current available at its line terminals

    NEC 110.9 requires that equipment intended to interrupt fault current have an interrupting rating sufficient for the nominal circuit voltage and the available fault current at its terminals.

  6. Per NEC 230.95(A), what is the maximum ground-fault trip current setting permitted for ground-fault protection of equipment (GFPE) on service equipment?

    Answer: 1200 amperes

    NEC 230.95(A) limits the maximum GFPE trip setting to 1200 amperes to ensure the device will operate before a destructive arcing ground fault causes catastrophic damage to switchgear or switchboards.

  7. Per NEC 110.15 and 230.56, the high-leg conductor of a 4-wire, 3-phase delta system shall be identified by the color:

    Answer: Orange

    NEC 110.15 and 230.56 require the high-leg conductor (the phase with the highest voltage to ground, approximately 208V) in a 4-wire delta system to be identified with orange color.