Test your knowledge of the National Electrical Code (NEC).
Created by: Michael Johnston
1. The term selective coordination means localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection and installation of overcurrent protective devices and their ratings or settings for the full range of available overcurrents, from overload to the maximum available fault current, and for the full range of overcurrent protective device opening times associated with those overcurrents.
2. Generally, ground-fault protection of equipment (GFPE) shall be provided for solidly grounded wye electric services of more than 150 volts (V) to ground but not exceeding _____V phase-to-phase for each service disconnect rated _____ amperes (A) or more.
A. 600; 600
B. 1,000; 1,000
C. 2,500; 1,200
D. 3,000; 100
3. Class A ground-fault circuit-interrupter (GFCI) protection is for protection against shock and electrocution, while GFPE is for protection of equipment.
4. GFPE is required for fire pumps or continuous industrial processes where a non-orderly shutdown would introduce additional or increased hazards.
5. The maximum current setting for service disconnect GFPE is _____A, and the maximum time delay for operation is _____ second(s) for ground-fault currents equal to or greater than 3,000A.
A. 600; 2
B. 1,000; 5
C. 1,200; 1
D. 3,000; 1
6. What is a system intended to provide equipment protection from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit? This protection is provided at current levels less than those required to protect conductors from damage through the operation of a supply circuit overcurrent device.
A. Arc-fault circuit interrupter protection
B. GFCI protection
D. Short-circuit protection
7. A(n) _____ is the operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating.
B. Selective coordination
8. Section 517.17(B) indicates, when GFPE is provided at the service or feeder disconnecting means, as specified by Section 230.95 or 215.10, an additional level of GFP is not required to be installed in the next level of feeder disconnecting means downstream toward the load.
9. The additional level of GFPE required by Section 517.17(B) is not permitted to be installed in which of the following locations or applications?
A. Between the on-site generating unit or units described in Section 517.35(B) and the essential system transfer switch or switches
B. On electrical systems that are not solidly grounded wye systems with greater than 150V to ground but not exceeding 1,000V phase-to-phase
C. On the load side of an essential electrical system transfer switch
D. All of the above
10. Sections 230.95(C) and 517.17(D) of the NEC require GFPE systems to be performance-tested when first installed on-site to ensure proper operation and selectivity.