Master Examination

Practice Drill #5 2011

Ted “Smitty” Smith

O Given: a 150 kVA service transformer has a 480Y/277 volt, 3-phase secondary. What is the approximate full-load ampere rating of the primary of the transformer?A. 180 amperesB. 312 amperesC. 542 amperesD. 416 amperes

O 1. A

O 180.32 A

O Where a conductor is marked RHW-2 on the insulation what does the -2 represent?A. The cable has 2 conductorsB. The conductor is double insulatedC. The conductor has a nylon outer

jacketD. The conductor has a maximum

operating temperature of 90°C.

O 2. D Table 310.104(A)

O For a grounded electrical system, the equipment grounding conductor shall be sized in accordance with ___________?A. The undergrounded circuit

conductorsB. The overcurrent protective deviceC. The service entrance conductorsD. The grounding electrode

O 3. B

O 250.32(B)(1)O Table 250.122

O Determine the allowable ampacity of a size kcmil THW aluminum conductor installed in a raceway with four (4) other current-carrying conductors when the expected ambient temperature is 44 deg. C.A. 151 amperesB. 164 amperesC. 210 amperesD. 146 amperes

O 4. B

O Tbl. 310.15(B)(16)O Tbl. 310.15(B)(2)(a)O Tbl. 310.15(B)(3)(a)

O Determine the MAXIMUM number of 120-volt, general-purpose duplex receptacles the NEC® permits to be protected by a 20-ampere, 120-volt single-pole circuit breaker in a commercial building.A. 18B. 15C. 13D. 10

O 5. CO 120 volts x 20 amperes= 2400 VAO 2400 VA / 180 VA= 13 receptacles

O For4 lighting systems operating at 30 volts or less, the output circuits of the power supply are to be rated for NOT more than ___________?A. 15 amperesB. 20 amperesC. 25 amperesD. 30 amperes

O 6. C

O 411.2

O Where there are tenant spaces in a retail shopping mall, each occupant shall have access to the main disconnecting means, EXCEPT:A. Where the service and maintenance

are provided by the building management.

B. Where there are more than six disconnecting means provided.

C. Where the primary feeder transformer does not exceed 600 volts.

D. Where the secondary of the service transformer does not exceed 240 volts to ground.

O 7. A

O 240.24(B)(1)(1)

O Determine the conductor allowable ampacity given the following related information:Ambient temperature of 44°C250 kcmil THWN copper conductorsFour (4) current-carrying conductors

in the racewayLength of raceway is 50 feet.

A. 160 amperesB. 167 amperesC. 200 amperesD. 209 amperes

O 8. B

O Tble. 310.15(B)(16)O Tbl. 310.15(B)(2)(a)O Tbl. 310.15(B)(3)(a)

O 250 kcmil THWN copper ampacity 255 A

O 255 A x .82 temp correction x .8 adj factor

O In general, the grounded conductor and the grounding conductor must be bonded together in _____________? I. Panelboards used as service

equipmentAll sub-panels

A. I onlyB. II only C. Both I and IID. Neither I not II

O 9. A

O 250.24(A)O 250.24(A)(5)O 408.3(C)

O Using the standard method of calculation, what is the demand, in kW, on the undergrounded service-entrance conductors of an apartment complex that has thirty-five (35) electric ranges rated at 11.5 kW each?A. 403 kWB. 15 kWC. 280 kWD. 50 kW

O 10. D

O Tbl 220.55, Col. C

O A grounding ring consisting of a size 2 AWG bare copper wire encircling a building, buried 36 in. deep, in direct contact with the earth, is required to have a MINIMUM length of ____________?A. 15 feetB. 20 feetC. 25 feetD. 50 feet

O 11. B

O 250.52(A)(4)

O Where applying the optional method of calculation for one-family dwelling, what is the demand load for the heating and cooling, in kW, on the ungrounded service-entrance conductors for a residence that has the following? One blower motor rated 1.2 kW, interlocked with

both space heating and AC equipment. One central electric space-heating unit rated 25 kW One air-conditioning unit rated 6.5 kW

A. 32.75 kWB. 25.00 kWC. 17.03 kWD. 26.20 kW

O 12. C

O 220.82(C) and (C)(4)

O Note: Use the large of the A/C or heating load

O Apply the general method of calculation for dwelling units and determine the Minimum demand load, in VA, where a one-family residence has the following fastened in place appliances.Microwave oven – 1,250 VATrash compacter – 960VADishwasher – 1,400 VAGarage door opener – 960 VA

A. 3,428 VAB. 3,656 VAC. C. 4,570D. 4,883 VA

O 13. A 220.53O Microwave Oven: 1250 VAO Trash Compactor: 960 VAO Dish Washer: 1400 VAO Garage Door Opener: 900 VaO Total: 4570 VA x .75= 3428 VA

O Where a service riser is installed in a wet location and contains THWN insulated conductors, the wiring method used ________________.A. Is permitted to be Type AC cableB. Shall be rigid metal conduit

(RMC)C. Is permitted to be electrical

metallic tubing (EMT)D. Shall be liquidtight flexible metal

conduit (LFMC)

O 14. C 230.43(5)

O What is the MAXIMUM distance between supports for straight horizontal runs of trade size 1 ½ in. threaded rigid metal conduit (RMC)?A. 10 feetB. 12 feetC. 14 feetD. 16 feet

O 15. C

O Tbl 344.30(B)(2)

O At least one receptacle outlet shall be installed directly above a show window of a department store for each __________ linear feet of show window area.A. SixB. EightC. Ten D. Twelve

O 16. D

O 210.62

O A thermal barrier shall be required if the space between the resistors and reactors, of 600 volts or less, and combustible material is Less than __________________?A. 12 inches B. 18 inchesC. 10 inchesD. 6 inches

O 17. A

O 470.3

O In movie theaters, all switches for controlling the emergency lighting systems shall be located __________.A. On the stageB. In the lobbyC. In the manger’s officeD. In the project booth

O 18. B

O 700.21

O Where a 90 ampere, 240-volt, single-phase load is located 225 feet from a panelboard and is supplied with size 3 AWG copper conductors, determine the approximate voltage drop on the conductors. (K=12.9)A. 6 voltsB. 4 voltsC. 8 voltsD. 10 volts

O 19. D

O VD= 2KDI/CMO 2x12.9x225x90/52620= 9.92

O A one-family residence is served with insulated 120/240 colt service-drop conductors, supported with a grounded messenger wire from the utility company. This service-drop crosses the swimming pool; the pool has a diving board that is 5 feet above the water level. The NEC® requires the conductors to be a Minimum height of ______ above the pool water level.A. 25 feetB. 14 ¼ feetC. 22 ½ feetD. 19 ½ feet

O 20. C

O Fig. 580.8O Tbl. 680.8

O Given: A trade size 2 in. electrical metallic tubing (EMT) containing four (4) size 2/0 AWG THWN copper conductors is to be installed in a pull box for a straight pull of the conductors. What is the MINIMUM required length of the pull box?A. 4 inchesB. 12 inches C. 16 inchesD. 24 inches

O 21. C

O 314.28

O 2x8= 16

O In a commercial garage work area, which of the following receptacles, if any, are required to have GFCI protection? I. 15 ampere general-purpose

receptacles for hand tools and portable lights.

II. 20 ampere receptacles serving electrical diagnostic equipment only.

A. I onlyB. II onlyC. Both I and IID. Neither I and II

O 22. C

O 210.8(B)(8)O 511.12

O Conductors tapped from a feeder and supplying the primary of a transformer need not have overcurrent protection, if the length of the tap conductors are not over 25 feet and have an ampacity of at LEAST ______ of the rating of the overcurrent device protecting the feeder conductors.A. One-thirdB. One-halfC. 80 percentD. 75 percent

O 23. A

O 240.21(B)(3)(1)

O Where conductors carrying alternating current are installed in ferrous metal raceways, ________.A. All phase conductors, the grounded

conductor and equipment grounding conductors shall be grouped together

B. The phase conductors shall not be grouped with the grounded conductor

C. The equipment grounding conductor is not permitted to be in the same raceway with the grounded and ungrounded conductors

D. The equipment grounding conductors are not permitted to be installed in a common raceway with the grounded conductors.

O 24. A

O 300.20(A)

O When connecting utilization equipment to a 20-ampere rated branch-circuit that also serves luminaires (lighting fixtures), the utilization equipment shall have an ampere rating of NOT more than _______.A. 10 amperesB. 15 amperesC. 16 amperesD. 12 amperes

O 25. AO 210.23(A)(2)O 20A x 50%= 10 A

Click Here to Proceed without the timer

O Given: a 150 kVA service transformer has a 480Y/277 volt, 3-phase secondary. What is the approximate full-load ampere rating of the primary of the transformer?A. 180 amperesB. 312 amperesC. 542 amperesD. 416 amperes

O 1. A

O 180.32 A

O Where a conductor is marked RHW-2 on the insulation what does the -2 represent?A. The cable has 2 conductorsB. The conductor is double insulatedC. The conductor has a nylon outer

jacketD. The conductor has a maximum

operating temperature of 90°C.

O 2. D Table 310.104(A)

O For a grounded electrical system, the equipment grounding conductor shall be sized in accordance with ___________?A. The undergrounded circuit

conductorsB. The overcurrent protective deviceC. The service entrance conductorsD. The grounding electrode

O 3. B

O 250.32(B)(1)O Table 250.122

O Determine the allowable ampacity of a size kcmil THW aluminum conductor installed in a raceway with four (4) other current-carrying conductors when the expected ambient temperature is 44 deg. C.A. 151 amperesB. 164 amperesC. 210 amperesD. 146 amperes

O 4. B

O Tbl. 310.15(B)(16)O Tbl. 310.15(B)(2)(a)O Tbl. 310.15(B)(3)(a)

O Determine the MAXIMUM number of 120-volt, general-purpose duplex receptacles the NEC® permits to be protected by a 20-ampere, 120-volt single-pole circuit breaker in a commercial building.A. 18B. 15C. 13D. 10

O 5. CO 120 volts x 20 amperes= 2400 VAO 2400 VA / 180 VA= 13 receptacles

O For4 lighting systems operating at 30 volts or less, the output circuits of the power supply are to be rated for NOT more than ___________?A. 15 amperesB. 20 amperesC. 25 amperesD. 30 amperes

O 6. C

O 411.2

O Where there are tenant spaces in a retail shopping mall, each occupant shall have access to the main disconnecting means, EXCEPT:A. Where the service and maintenance

are provided by the building management.

B. Where there are more than six disconnecting means provided.

C. Where the primary feeder transformer does not exceed 600 volts.

D. Where the secondary of the service transformer does not exceed 240 volts to ground.

O 7. A

O 240.24(B)(1)(1)

O Determine the conductor allowable ampacity given the following related information:Ambient temperature of 44°C250 kcmil THWN copper conductorsFour (4) current-carrying conductors

in the racewayLength of raceway is 50 feet.

A. 160 amperesB. 167 amperesC. 200 amperesD. 209 amperes

O 8. B

O Tble. 310.15(B)(16)O Tbl. 310.15(B)(2)(a)O Tbl. 310.15(B)(3)(a)

O 250 kcmil THWN copper ampacity 255 A

O 255 A x .82 temp correction x .8 adj factor

O In general, the grounded conductor and the grounding conductor must be bonded together in _____________? I. Panelboards used as service

equipmentAll sub-panels

A. I onlyB. II only C. Both I and IID. Neither I not II

O 9. A

O 250.24(A)O 250.24(A)(5)O 408.3(C)

O Using the standard method of calculation, what is the demand, in kW, on the undergrounded service-entrance conductors of an apartment complex that has thirty-five (35) electric ranges rated at 11.5 kW each?A. 403 kWB. 15 kWC. 280 kWD. 50 kW

O 10. D

O Tbl 220.55, Col. C

O A grounding ring consisting of a size 2 AWG bare copper wire encircling a building, buried 36 in. deep, in direct contact with the earth, is required to have a MINIMUM length of ____________?A. 15 feetB. 20 feetC. 25 feetD. 50 feet

O 11. B

O 250.52(A)(4)

O Where applying the optional method of calculation for one-family dwelling, what is the demand load for the heating and cooling, in kW, on the ungrounded service-entrance conductors for a residence that has the following? One blower motor rated 1.2 kW, interlocked with

both space heating and AC equipment. One central electric space-heating unit rated 25 kW One air-conditioning unit rated 6.5 kW

A. 32.75 kWB. 25.00 kWC. 17.03 kWD. 26.20 kW

O 12. C

O 220.82(C) and (C)(4)

O Note: Use the large of the A/C or heating load

O Apply the general method of calculation for dwelling units and determine the Minimum demand load, in VA, where a one-family residence has the following fastened in place appliances.Microwave oven – 1,250 VATrash compacter – 960VADishwasher – 1,400 VAGarage door opener – 960 VA

A. 3,428 VAB. 3,656 VAC. C. 4,570D. 4,883 VA

O 13. A 220.53O Microwave Oven: 1250 VAO Trash Compactor: 960 VAO Dish Washer: 1400 VAO Garage Door Opener: 900 VaO Total: 4570 VA x .75= 3428 VA

O Where a service riser is installed in a wet location and contains THWN insulated conductors, the wiring method used ________________.A. Is permitted to be Type AC cableB. Shall be rigid metal conduit

(RMC)C. Is permitted to be electrical

metallic tubing (EMT)D. Shall be liquidtight flexible metal

conduit (LFMC)

O 14. C 230.43(5)

O What is the MAXIMUM distance between supports for straight horizontal runs of trade size 1 ½ in. threaded rigid metal conduit (RMC)?A. 10 feetB. 12 feetC. 14 feetD. 16 feet

O 15. C

O Tbl 344.30(B)(2)

O At least one receptacle outlet shall be installed directly above a show window of a department store for each __________ linear feet of show window area.A. SixB. EightC. Ten D. Twelve

O 16. D

O 210.62

O A thermal barrier shall be required if the space between the resistors and reactors, of 600 volts or less, and combustible material is Less than __________________?A. 12 inches B. 18 inchesC. 10 inchesD. 6 inches

O 17. A

O 470.3

O In movie theaters, all switches for controlling the emergency lighting systems shall be located __________.A. On the stageB. In the lobbyC. In the manger’s officeD. In the project booth

O 18. B

O 700.21

O Where a 90 ampere, 240-volt, single-phase load is located 225 feet from a panelboard and is supplied with size 3 AWG copper conductors, determine the approximate voltage drop on the conductors. (K=12.9)A. 6 voltsB. 4 voltsC. 8 voltsD. 10 volts

O 19. D

O VD= 2KDI/CMO 2x12.9x225x90/52620= 9.92

O A one-family residence is served with insulated 120/240 colt service-drop conductors, supported with a grounded messenger wire from the utility company. This service-drop crosses the swimming pool; the pool has a diving board that is 5 feet above the water level. The NEC® requires the conductors to be a Minimum height of ______ above the pool water level.A. 25 feetB. 14 ¼ feetC. 22 ½ feetD. 19 ½ feet

O 20. C

O Fig. 580.8O Tbl. 680.8

O Given: A trade size 2 in. electrical metallic tubing (EMT) containing four (4) size 2/0 AWG THWN copper conductors is to be installed in a pull box for a straight pull of the conductors. What is the MINIMUM required length of the pull box?A. 4 inchesB. 12 inches C. 16 inchesD. 24 inches

O 21. C

O 314.28

O 2x8= 16

O In a commercial garage work area, which of the following receptacles, if any, are required to have GFCI protection? I. 15 ampere general-purpose

receptacles for hand tools and portable lights.

II. 20 ampere receptacles serving electrical diagnostic equipment only.

A. I onlyB. II onlyC. Both I and IID. Neither I and II

O 22. C

O 210.8(B)(8)O 511.12

O Conductors tapped from a feeder and supplying the primary of a transformer need not have overcurrent protection, if the length of the tap conductors are not over 25 feet and have an ampacity of at LEAST ______ of the rating of the overcurrent device protecting the feeder conductors.A. One-thirdB. One-halfC. 80 percentD. 75 percent

O 23. A

O 240.21(B)(3)(1)

O Where conductors carrying alternating current are installed in ferrous metal raceways, ________.A. All phase conductors, the grounded

conductor and equipment grounding conductors shall be grouped together

B. The phase conductors shall not be grouped with the grounded conductor

C. The equipment grounding conductor is not permitted to be in the same raceway with the grounded and ungrounded conductors

D. The equipment grounding conductors are not permitted to be installed in a common raceway with the grounded conductors.

O 24. A

O 300.20(A)

O When connecting utilization equipment to a 20-ampere rated branch-circuit that also serves luminaires (lighting fixtures), the utilization equipment shall have an ampere rating of NOT more than _______.A. 10 amperesB. 15 amperesC. 16 amperesD. 12 amperes

O 25. AO 210.23(A)(2)O 20A x 50%= 10 A