Midterm Exam

15. Rather than make a grounding connection in each service disconnecting means for services that are double-ended, it is permitted to make a single grounding electrode connection at the tie point for services. a. True b. False

a. True

35. Which of the following statements about painted electrical enclosures is not true? a. paint used on electrical enclosures can be thought of as an insulator b. where conduit, emt, or metal cables are connected to these enclosures paint should be removed c. fittings and locknuts are readily available that are listed to make removal of paint unnecessary d. every connection in the ground return path should be evaluated to ensure it is a good, solid connection that is capable of carrying fault current

c. fittings and locknuts are readily available that are listed to make removal of paint unnecessary

13. If more than one path exists for neutral current to flow, the current will flow a. in only one path of lowest resistance b. in only the paths that are in series c. in all paths available d. only when there is a ground-fault

c. in all paths available

26. Where operating at less than 50 volts, A/C systems are required to be grounded where supplied by transformers if the transformer supply system exceeds ___ volts to ground. a. 100 b. 110 c. 140 d. 150

d. 150

38. Which of the following systems in not required to be grounded? a. 120-volt, 1-phase, 2-wire b. 120/240- volt, 1-phase, 3 wire c. 208Y/120-volt, 3-phase, 4-wire, wye-connected d. 240-volt, 3-[phase, 3-wire

d. 240-volt, 3-phase, 3-wire

33. Which of the following is not permitted for the bonding required by 250.97? a. threadless couplings and connectors for cables with metal sheaths b. two locknuts, on rigid metal conduit or intermediate metal conduit, one inside and one outside c. fittings with shoulders that seat firmly against a box or cabinet, with one locknut inside d. one locknut outside the enclosure and one metal bushing inside the enclosure for rigid or intermediate metal conduit

d. one locknut outside the enclosure and one metal bushing inside the enclosure for rigid or intermediate metal conduit

7. Because separately derived systems are not a service, it is generally permitted to ground the neutral at multiple locations on the load side of the separately derived system. a. True b. False

False

24. Ungrounded systems are required to be legibly marked at the first disconnecting means with a label or some other identifying means. This warning label should indicate the following: a. "Warning: ungrounded systems can be dangerous" b. "Caution: ungrounded systems do not include a grounded conductor" c. "Caution: ungrounded system operating ____ volts between conductors" d. " Warning: Qualified Personnel Only"

c. "Caution: ungrounded system operating ____ volts between conductors"

22. The minimum size copper grounded conductor required for a separately derived system where the derived phase conductors are 300 kcmil cu conductors (1 per phase) and there is very little or no neutral load on the system is _____. a. 6 AWG b. 1/0 AWG c. 2 AWG d. 2/0 AWG

c. 2 AWG

25. Where multiple separately derived systems are installed and connected to a common grounding electrode conductor, the minimum size of the copper grounding electrode conductor must not be smaller than ____. a. 6 AWG b. 250 kcmil c. 4 AWG d. 3/0

c. 4 AWG

39. Which of the following terms is not used to describe an effective ground fault path? a. intentionally constructed b. low impedance c. 6 AWG or larger d. continuous and reliable

c. 6 AWG or larger

40. Which of the following underground water pipes is not recognized as a grounding electrode in 250.52 (A)(1)? a. 3/4 in. galvanized in contact with the earth for 22ft. b. 1 in. copper in contact with the earth for 28ft. c. 6 in. iron half-wrapped with corrosion-protection tape in contact with the earth for 40ft. d. 3/4 in. copper in contact with the earth for 12 ft.

c. 6 in. iron half-wrapped with corrosion-protection tape in contact with the earth for 40ft.

27. Where the common grounding electrode conductor tap system is used for grounding multiple separately derived system, the grounding electrode conductor taps shall be connected in a manner that the ____ remains without a splice or joint. a. equipment grounding conductor b. grounded conductor c. common grounding electrode conductor d. equipment bonding jumper

c. common grounding electrode conductor

23. The minimum size of the grounded conductor for a 3-phase, 3-wire, corner-grounded, delta connected service is a. not smaller than the required grounding electrode conductor b. not smaller than a neutral for a 3-phase, wye-connected system or same ampacity c. not smaller than the ungrounded service conductors d. not specified as a grounded conductor is not required

c. not smaller than the ungrounded service conductors

17. The effective ground-fault current path must be installed in a manner that creates a path that is ____. a. electrically continuous b. has the capacity to conduct safely the maximum ground-fault current likely to be imposed on it c. has sufficiently low impedance to limit the voltage to ground and to facilitate the operation of the over-current protective device. d. all of the above

d. all of the above

32. Which of the following enclosures for service conductors are required to be bonded? a. service raceways, cable trays, and auxiliary gutters b. meter fittings, boxes, or similar enclosures c. any metallic raceway or armor enclosing a grounding electrode conductor d. all of the above

d. all of the above

9. Equipment bonding jumpers are permitted to consist of a. wire b. bus c. screw d. any of the above

d. any of the above

2. A sheet metal enclosure must not be less than ___ thick if a machine screw type fastener of the 10-32 size is used to connect an equipment grounding conductor to the enclosure. a. 1/32 in. b. 1/16 in. c. 3/32 in. d. 1/8 in.

b. 1/16 in.

34. Which of the following phrases best describes the term grounded conductor? a. a system or circuit conductor that is intentionally grounded b. a conductor used to connect the neutral and equipment grounding conductors c. the midpoint of a wye-connected transformer bank d. the conductor used to connect exposed conductive surfaces together

a. a system or circuit conductor that is intentionally grounded

16. Some utility policies prohibit a grounding electrode conductor connection within metering equipment, and many inspection authorities prohibit that connection location because they interpret the connection to be no longer ____. a. accessible b. identified c. serviceable d. visible

a. accessible

14.Keeping all circuit conductors, including the equipment grounding conductor, in the same raceway, cable or similar enclosure is essential to keep the ____ as low as practicable. a. impedance b. resistance c. inductance d. capacitance

a. impedance

10. For current to be present there must be a complete ______. a. grounding conductor b. conduit system c. circuit d. overcurrent protective device

c. circuit

4. A/C system grounding is not required for 50 to 1000 volts electric systems used exclusively to supply industrial electric furnaces for _____. a. melting b. refining c. tempering d. all of the above

d. all of the above

36. Which of the following statements about providing an effective ground-fault current path is not true? a. it must be reliable rather than a temporary path b. it must provide a low-impedance circuit c. it must be capable of carrying the maximum ground-fault current likely to be imposed d. it permits the earth to be considered an effective ground-fault current path

d. it permits the earth to be considered an effective ground-fault current path

18. The equipment grounding conductor a. connects normally non-current carrying metal parts together. b. connects equipment to the system ground conductor. c. connects equipment to the grounding electrode d. performs all of the above functions

d. performs all of the above functions

3. A _____ premises wiring system is one that is derived from a source of electric energy or equipment other than a service such as, a generator, transformer or converter windings that have no direct connection to the circuit conductors originating in another system, except through grounding and bonding. a. identified b. open neutral c. isolated power d. separately derived

d. separately derived

30. Which of the following connection methods is not permitted to be used to connect grounding conductors to enclosures or equipment? a. exothermic welding b. listed pressure connectors c. listed clamps d. sheet metal screws

d. sheet metal screws

28.Where the generator is not a separately derived system, the ____ bonding jumper must be removed from the generator and the neutral conductor must not be grounded. In this case, the system is grounded by it's solid connection to the grounded conductor of the premises wiring system. a. 10 AWG b. equipment c. service d. system

d. system

31. Which of the following descriptions is the best definition of the term bonding (bonded)? a. connected to a grounded panel board enclosure b. a device that makes a connection to the earth c. driving a local ground rod at the equipment d. the permanent joining of metallic parts to form an electrically conductive path

d. the permanent joining of metallic parts to form an electrically conductive path

1. A grounded electronically conductive object is forced to take the same potential as the ____. Select one: a. electrode b. metal raceway c. ground (the earth) d. system

. ground (the earth)

29. Which of the following best describes the definition of ground? a. connected to the earth b. a grounding electrode c. the earth d. equipment grounding conductor

. the earth

11. For sets of ungrounded service-entrance conductors larger than 1100 kcmil copper and 1750 kcmil aluminum, the grounded conductor cannot be smaller than ___ percent of the area of the largest service-entrance conductor. a. 12.5 b. 14.5 c. 13 d. 12

a. 12.5

20. The higher the impedance or resistance of a circuit, the ____ amount of current in the circuit. a. lower b. higher c. same d. different

a. lower

37. Which of the following statements does not describe objectionable current? a. neutral current flowing over the grounded (neutral) conductor b. neutral current flowing over the equipment grounding conductor c. neutral current flowing over cable shields d. neutral current flowing over metal conduit

a. neutral current flowing over the grounded (neutral) conductor

6. An over current included all of the following except _____. a. phase fault b. short circuit c. overload d. ground-fault

a. phase fault

12. Ground detection systems are required to be installed to indicate that a ground fault has occurred on the ___ systems. a. ungrounded b. grounded c. bonded d. identified

a. ungrounded

5. A/C system grounding is required for 50 to 1000 volts systems supplying premise wiring or premise wiring systems where the system can be grounded so the maximum voltage to ground on the ungrounded conductors does not exceed ___ volts. a. 180 b. 150 c. 240 d. 208

b. 150

8. Derived phase conductors supplied by a separately derived system sized at 500 kcmil aluminum generally required a grounding electrode conductor not smaller than ____. a. 4 AWG cu or 2 AWG al b. 2 AWG cu or 1/0 AWG al c. 6 AWG cu or 4 AWG al d. 8 AWG cu or 6 AWG al

b. 2 AWG cu or 1/0 AWG al

21. The minimum size bonding jumper from the building disconnecting means to the metal water pipe if the building is supplied by a 600 amp feeder consisting of 2 350-kcmil copper conductors in parallel is a. 3/0 AWG copper b. 2/0 AWG copper c. 1/0 AWG copper d. 1 AWG copper

b. 2/0 AWG copper

19. The grounding electrode for a lightning protection system is required to be completely separate from the grounding electrode system for the electrical service and the electrodes are not permitted to be bonded together. a. True b. False

b. False