E2 Overcurrent Protection Devices 3

Question 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:

Accepted Answer

800 amperes

Answer

200 amperes

Answer

400 amperes

Answer

600 amperes

Question 2

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

Accepted Answer

Either solidly grounded or ungrounded systems at that voltage

Answer

Solidly grounded systems only

Answer

Ungrounded systems only

Answer

Resistance-grounded systems only

Question 3

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

Accepted Answer

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

Answer

Limits current to the conductor's rated ampacity under all fault conditions

Answer

Prevents any fault current from reaching the load side

Answer

Limits the duration of any overcurrent to exactly one half-cycle

Question 4

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

Accepted Answer

The occupant of the dwelling unit that is protected

Answer

The building owner or property manager only

Answer

All tenants in the building equally

Answer

Only qualified electrical personnel

Question 5

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

Accepted Answer

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

Answer

Of at least 10,000 amperes symmetrical RMS

Answer

Of at least 22,000 amperes symmetrical RMS

Answer

Marked on the nameplate with a minimum of 5,000 AIC

Question 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?

Accepted Answer

1200 amperes

Answer

400 amperes

Answer

800 amperes

Answer

1600 amperes

Question 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:

Accepted Answer

Orange

Answer

Red

Answer

Blue

Answer

Yellow