Calculation Speed Drill # 3 2008 NEC ©Ted “Smitty” Smith 2008, 2011 THIS DRILL MAY ALSO BE USED IN ACCORDANCE WITH THE 2011 NEC.

Instructions This speed drill focuses on calculations that will be required for the journeyman and masters examination. The question slide will still transition in 3 ½ minutes for calculations and 2 mins for code look up questions and will be followed by the correct answer which will stay on the screen for only 10 seconds. Do not worry about writing down the correct answer during the transition. At the end of the questions, a stop slide will appear and then that will be followed by the questions and answers without the timer so you can review them. You must click on the screen icon in the lower right hand or left corner of the tool bar to start the slide show in order for the timer to operate.

How many watts is used by a 10 hp motor?

7460 Watts 746 x 10= 7460

What is the ampacity of NM cables installed in a bored hole if the cables are 10-2 with ground and there are a total of three cables installed in the bored hole?

30 amperes 334.80 Must derate based on 90 C column and conductors in a raceway or cable table. There are six current carrying conductors. 10 AWG is 40 amperes and six conductors requires .80 derating. 40X.80= 32 334.80 also states that the adjusted ampacity can not exceed the value found in the 60 C column of 310.16. 60 C column is 30 amperes for #10 AWG copper.

What is the minimum sized equipment grounding conductor required for a circuit that is supplied by a 400A inverse time, overcurrent protective device?

Table 250.122 #3 Copper or #1 Aluminum

A disconnecting means for an emergency system or fire pump shall be installed __________________ from the one to six service disconnecting means for normal service. Copyright 2005 Ted "Smitty" Smith

Remote, away from 230.72

IMC conduit shall be installed so that it is supported in intervals not exceeding ___________ feet? Copyright 2005 Ted "Smitty" Smith

10 feet 342.30(B)

Motor Calculation What is the maximum branch circuit- short circuit protection allowed for a 208V, three phase, squirrel cage motor with the following nameplate ratings: 20 hp, 51.6 A FLC, 1.15 Service Factor, and Design B The short circuit protection will be done with an inverse time circuit breaker.

Motor Calculation 150 ampere inverse time breaker.

Raceway Fill What is the minimum trade name size conduit that can be used for a 310 foot conduit run that will contain nine 10 AWG TW conductors, five 2 AWG RHW conductors with outer covering, and two 6 AWG RHH conductors that do not have an outer covering? The wires will be installed in an intermediate metal conduit.

Raceway Fill The total area of the conductors is 1.0934 and a 2” IMC at 31% fill will allow 1.125. 2”

1. Standard trade size 2-inch rigid polyvinyl chloride conduit (PVC), shall be supported at least every _____. 3 feet 5 feet 6 feet 8 feet Ted "Smitty" Smith 4/22/2017

1. b Tbl. 352.30 Ted "Smitty" Smith 4/22/2017

inverse-time circuit breakers Non-time-delay fuses 2. When sizing time-delay Class CC fuses for motor branch-circuit, short-circuit, and ground-fault protection, they are to be sized at the same value as _____. inverse-time circuit breakers Non-time-delay fuses Instantaneous trip circuit breakers Adjustable trip circuit breakers Ted "Smitty" Smith 4/22/2017

2. b Tbl. 430.52,Note 1 Ted "Smitty" Smith 4/22/2017

3. Where sizes 1/0 AWG single conductor cables are installed in ladder type cable tray, the MAXIMUM allowable rung spacing for the ladder cable tray shall be _____. 6 inches 9 inches 12 inches 15 inches Ted "Smitty" Smith 4/22/2017

3. b 392.3(B)(1)(a) Ted "Smitty" Smith 4/22/2017

4. The NEC® requires the MAXIMUM length permitted for a flexible cord supplying a 208-volt, single-phase, room air-conditioner to be ____. 4 feet 6 feet 8 feet 10 feet Ted "Smitty" Smith 4/22/2017

4. b 440.64 Ted "Smitty" Smith 4/22/2017

All 125-volt, single phase, 15- and 20-ampere rated receptacles. 5. In general, which of the following receptacle outlets in a commercial kitchen are required by the NEC® to be GFCI protected? All 125-volt, single phase, 15- and 20-ampere rated receptacles. All 125-volt, 15- or 20-ampere rated receptacles in wet locations only. All receptacle outlets. All 125-volt countertop receptacle outlets only. Ted "Smitty" Smith 4/22/2017

5. a 210.8(B)(2) Ted "Smitty" Smith 4/22/2017

6. All wiring installed in or under an aircraft hanger floor shall comply with the requirements for ______ locations. Class I, Division 1 Class I, Division 2 Class II, Division 1 Class II, Division 2 Ted "Smitty" Smith 4/22/2017

6. a 513.8(A) Ted "Smitty" Smith 4/22/2017

7. In general, branch-circuit conductors supplying more than one motor shall have an ampacity of a at least _____ percent of the FLC of the largest motor, and 100 percent of the FLC of the other motor(s) in the group. 25 80 100 125 Ted "Smitty" Smith 4/22/2017

7. d 430.24 Ted "Smitty" Smith 4/22/2017

8. What is the MINIMUM size equipment grounding conductor required for a 5 HP, three-phase, 208-volt motor having 20-ampere rated overload protection and short-circuit overcurrent protection rated at 30 amperes? 10 AWG 14 AWG 12 AWG 8 AWG Ted "Smitty" Smith 4/22/2017

8. a Tbl. 250.122 Ted "Smitty" Smith 4/22/2017

The motor to be less than 2 HP. 9. If a circuit breaker serves as the controller for a motor, and the motor is not in sight of the breaker, the NEC® requires which of the following? The motor to be less than 2 HP. The breaker be able to be locked in the open position. The motor to be Code letter “E”. The breaker to be rated 25,000 AIC. Ted "Smitty" Smith 4/22/2017

9. b 430.102(B)(2), Ex. Ted "Smitty" Smith 4/22/2017

10. In Class II, Division 1, hazardous locations, an approved method of connection of conduit to boxes is _____. Compression fittings Threaded bosses Welding All of these Ted "Smitty" Smith 4/22/2017

10. b 502.10(A)(4) Ted "Smitty" Smith 4/22/2017

11. Given: an AC service is supplied with four parallel kcmil aluminum conductors. What is the MINIMUM size copper grounding electrode required, when connected to the concrete-encased building steel used as the grounding electrode system? 3/0 AWG 4/0 AWG 250 kcmil 2/0 AWG Ted "Smitty" Smith 4/22/2017

500 kcmil X 4 conductors = 2000 kcmil total 11. a Tbl. 250.66 500 kcmil X 4 conductors = 2000 kcmil total *NOTE: Aluminum service-entrance conductors over 1750 kcmil require a size 3/0 AWG copper grounding electrode conductor. Ted "Smitty" Smith 4/22/2017

12. Given: an AC transformer arc welder has a 50- ampere rated primary current and a 60 percent duty-cycle. Determine the MINIMUM size copper 60°C rated conductors the NEC® requires to supply this welder. 6 AWG 8 AWG 10 AWG 4 AWG Ted "Smitty" Smith 4/22/2017

.78 (duty cycle) X 50 amperes (primary current) = 39 amperes 12. b Tbl. 630.11(A) Tbl. 310.16 .78 (duty cycle) X 50 amperes (primary current) = 39 amperes Tbl. 310.16 requires a size 8 AWG conductor. Ted "Smitty" Smith 4/22/2017

13. When installing wiring for sensitive electronic equipment, the MAXIMUM voltage to ground is required to be ____ volts. 30 60 120 300 Ted "Smitty" Smith 4/22/2017

13. b 647.1 Ted "Smitty" Smith 4/22/2017

Stop This is the end of the presentation. You can now review the slides and answers without the timer. Click the slide to advance to the next slide

Calculation Speed Drill # 3 2008 NEC ©Ted “Smitty” Smith 2008

Instructions This speed drill focuses on calculations that will be required for the journeyman and masters examination. The question slide will still transition in 3 ½ minutes and will be followed by the correct answer which will stay on the screen for only 10 seconds. Do not worry about writing down the correct answer during the transition. At the end of the questions, a stop slide will appear and then that will be followed by the questions and answers without the timer so you can review them. You must click on the screen icon in the lower right hand or left corner of the tool bar to start the slide show in order for the timer to operate.

How many watts is used by a 10 hp motor?

7460 Watts 746 x 10= 7460

What is the ampacity of NM cables installed in a bored hole if the cables are 10-2 with ground and there are a total of three cables installed in the bored hole?

30 amperes 334.80 Must derate based on 90 C column and conductors in a raceway or cable table. There are six current carrying conductors. 10 AWG is 40 amperes and six conductors requires .80 derating. 40X.80= 32 334.80 also states that the adjusted ampacity can not exceed the value found in the 60 C column of 310.16. 60 C column is 30 amperes for #10 AWG copper.

What is the minimum sized equipment grounding conductor required for a circuit that is supplied by a 400A inverse time, overcurrent protective device?

Table 250.122 #3 Copper or #1 Aluminum

A disconnecting means for an emergency system or fire pump shall be installed __________________ from the one to six service disconnecting means for normal service. Copyright 2005 Ted "Smitty" Smith

Remote, away from 230.72

IMC conduit shall be installed so that it is supported in intervals not exceeding ___________ feet? Copyright 2005 Ted "Smitty" Smith

10 feet 342.30(B)

Motor Calculation What is the maximum branch circuit- short circuit protection allowed for a 208V, three phase, squirrel cage motor with the following nameplate ratings: 20 hp, 51.6 A FLC, 1.15 Service Factor, and Design B The short circuit protection will be done with an inverse time circuit breaker.

Motor Calculation 150 ampere inverse time breaker.

Raceway Fill What is the minimum trade name size conduit that can be used for a 310 foot conduit run that will contain nine 10 AWG TW conductors, five 2 AWG RHW conductors with outer covering, and two 6 AWG RHH conductors that do not have an outer covering? The wires will be installed in an intermediate metal conduit.

Raceway Fill The total area of the conductors is 1.0934 and a 2” IMC at 31% fill will allow 1.125. 2”

1. Standard trade size 2-inch rigid polyvinyl chloride conduit (PVC), shall be supported at least every _____. 3 feet 5 feet 6 feet 8 feet Ted "Smitty" Smith 4/22/2017

1. b Tbl. 352.30 Ted "Smitty" Smith 4/22/2017

inverse-time circuit breakers Non-time-delay fuses 2. When sizing time-delay Class CC fuses for motor branch-circuit, short-circuit, and ground-fault protection, they are to be sized at the same value as _____. inverse-time circuit breakers Non-time-delay fuses Instantaneous trip circuit breakers Adjustable trip circuit breakers Ted "Smitty" Smith 4/22/2017

2. b Tbl. 430.52,Note 1 Ted "Smitty" Smith 4/22/2017

3. Where sizes 1/0 AWG single conductor cables are installed in ladder type cable tray, the MAXIMUM allowable rung spacing for the ladder cable tray shall be _____. 6 inches 9 inches 12 inches 15 inches Ted "Smitty" Smith 4/22/2017

3. b 392.3(B)(1)(a) Ted "Smitty" Smith 4/22/2017

4. The NEC® requires the MAXIMUM length permitted for a flexible cord supplying a 208-volt, single-phase, room air-conditioner to be ____. 4 feet 6 feet 8 feet 10 feet Ted "Smitty" Smith 4/22/2017

4. b 440.64 Ted "Smitty" Smith 4/22/2017

All 125-volt, single phase, 15- and 20-ampere rated receptacles. 5. In general, which of the following receptacle outlets in a commercial kitchen are required by the NEC® to be GFCI protected? All 125-volt, single phase, 15- and 20-ampere rated receptacles. All 125-volt, 15- or 20-ampere rated receptacles in wet locations only. All receptacle outlets. All 125-volt countertop receptacle outlets only. Ted "Smitty" Smith 4/22/2017

5. a 210.8(B)(2) Ted "Smitty" Smith 4/22/2017

6. All wiring installed in or under an aircraft hanger floor shall comply with the requirements for ______ locations. Class I, Division 1 Class I, Division 2 Class II, Division 1 Class II, Division 2 Ted "Smitty" Smith 4/22/2017

6. a 513.8(A) Ted "Smitty" Smith 4/22/2017

7. In general, branch-circuit conductors supplying more than one motor shall have an ampacity of a at least _____ percent of the FLC of the largest motor, and 100 percent of the FLC of the other motor(s) in the group. 25 80 100 125 Ted "Smitty" Smith 4/22/2017

7. d 430.24 Ted "Smitty" Smith 4/22/2017

8. What is the MINIMUM size equipment grounding conductor required for a 5 HP, three-phase, 208-volt motor having 20-ampere rated overload protection and short-circuit overcurrent protection rated at 30 amperes? 10 AWG 14 AWG 12 AWG 8 AWG Ted "Smitty" Smith 4/22/2017

8. a Tbl. 250.122 Ted "Smitty" Smith 4/22/2017

The motor to be less than 2 HP. 9. If a circuit breaker serves as the controller for a motor, and the motor is not in sight of the breaker, the NEC® requires which of the following? The motor to be less than 2 HP. The breaker be able to be locked in the open position. The motor to be Code letter “E”. The breaker to be rated 25,000 AIC. Ted "Smitty" Smith 4/22/2017

9. b 430.102(B)(2), Ex. Ted "Smitty" Smith 4/22/2017

10. In Class II, Division 1, hazardous locations, an approved method of connection of conduit to boxes is _____. Compression fittings Threaded bosses Welding All of these Ted "Smitty" Smith 4/22/2017

10. b 502.10(A)(4) Ted "Smitty" Smith 4/22/2017

11. Given: an AC service is supplied with four parallel kcmil aluminum conductors. What is the MINIMUM size copper grounding electrode required, when connected to the concrete-encased building steel used as the grounding electrode system? 3/0 AWG 4/0 AWG 250 kcmil 2/0 AWG Ted "Smitty" Smith 4/22/2017

500 kcmil X 4 conductors = 2000 kcmil total 11. a Tbl. 250.66 500 kcmil X 4 conductors = 2000 kcmil total *NOTE: Aluminum service-entrance conductors over 1750 kcmil require a size 3/0 AWG copper grounding electrode conductor. Ted "Smitty" Smith 4/22/2017

12. Given: an AC transformer arc welder has a 50- ampere rated primary current and a 60 percent duty-cycle. Determine the MINIMUM size copper 60°C rated conductors the NEC® requires to supply this welder. 6 AWG 8 AWG 10 AWG 4 AWG Ted "Smitty" Smith 4/22/2017

.78 (duty cycle) X 50 amperes (primary current) = 39 amperes 12. b Tbl. 630.11(A) Tbl. 310.16 .78 (duty cycle) X 50 amperes (primary current) = 39 amperes Tbl. 310.16 requires a size 8 AWG conductor. Ted "Smitty" Smith 4/22/2017

13. When installing wiring for sensitive electronic equipment, the MAXIMUM voltage to ground is required to be ____ volts. 30 60 120 300 Ted "Smitty" Smith 4/22/2017

13. b 647.1 Ted "Smitty" Smith 4/22/2017

Stop This is the end of the presentation. You can now review the slides and answers without the timer. Click the slide to advance to the next slide