Review 4

You installed a 3-pole 300-A breaker in a panel to feed a motor. Although the plans required only 3 AWG circuit conductors to the motor, you ran 1 AWG because of the long length of the circuit. The smallest EGC you can run with the circuit is ___ AWG. Select one: a. 6 b. 2 c. 3 d. 1 e. 4

1 Refer to Chapter 9, Table 8 #4 AWG-41,740 #3AWG-52,620 #1AWG-83,690 52,620/83,690=62% 41,470x62%=67,322 or 1 AWG

Refer to the nameplate shown in Figure 230.127. The branch circuit for the motor is supplied from a 277/480-volt, 3Ø, 4-wire panelboard. A NEMA size ___ starter is the smallest that could be used. Select one: a. 2 b. 00 c. 0 d. 1 e. 3

1 Refer to Y2 Annex N-6

Refer to the nameplate and information shown in Figure 230.132. The smallest EGC permitted with Nontime delay fuses is ___ AWG. 430.52(C)(1) Exc 1 was used to determine the largest permitted fuses. Select one: a. 12 b. 10 c. 8 d. 6 e. 14

10

Motor Nameplate Information: 115/230-V 1Ø 5 hp Supply: 2-pole breaker in a 120/240-V, 1-ph, 3-W panel Minimum size circuit conductors are ___ AWG. Select one: a. 6 b. 8 c. 4 d. 3 e. 10

10 Refer to Table 430.248 & Table 310.16 28Ax1.25=35A or 10 AWG

The nameplate for a 15 hp, three-phase motor shows an FLA of 20 amps at 460 volts. What minimum size wire is required for this motor? Select one: a. 14 b. 8 c. 12 d. 10 e. 6

10 Refer to Table 430.250 & Table 310.16 21x1.25=26.25A or 10 AWG

Refer to the nameplate and information shown in Figure 230.132. The smallest branch circuit conductors permitted are ___ AWG. Select one: a. 6 b. 10 c. 12 d. 8 e. 4

10 Refer to Table 430.250 & Table 310.16 27Ax1.25=33.75A or 10 AWG

Refer to Figure 230.261. Between the panel and the wireway, the minimum size circuit conductors for Motor #3 are ___ AWG. Count the number of circuit conductors in the conduit and determine ampacity inside the conduit from the 90º column. Select one: a. 8 b. 4 c. 6 d. 12 e. 10

10 Refer to Table 430.250, 310.15(B)(3)(a)& Table 310.16(90 degree) 22Ax1.25=27.5A 27.5/.7=39.3A or 10 AWG

The smallest permitted circuit conductors are to be installed to feed a 2 hp, 115/230-V, single-phase motor. The circuit is supplied from a 1-pole breaker in a 120/208-V, 3-ph, 4-W panel. The maximum permitted size ITCB [utilizing Exception 1 to 430.52(C)(1)] was installed for the motor circuit. Under these conditions, the minimum size EGC permitted is ___ AWG. Select one: a. 6 b. 10 c. 8 d. 14 e. 12

10 Refer to Tables 430.250, 310.16 & 250.122 24Ax1.25=30A or 10 AWG(310.16) 24Ax2.5=60A or 10 AWG(250.122)

Motor Nameplate Information: 3 hp 208-V 1Ø Branch Circuit Supply: 2-pole breaker in a 120/208-V, 3-ph, 4-W panel The smallest permitted circuit conductors are used in Scenario 230-27. Utilizing 430.52(C)(1) Exc. 1, an ITCB with a maximum permitted rating was installed. The minimum size EGC permitted for this installation is ___ AWG. Select one: a. 8 b. 6 c. 10 d. 12 e. 14

12 Refer to Tables 430.250, 310.16 & 250.122 19.6Ax1.25=24.5A or 12 AWG(310.16) 19.6Ax2.5=49A or 10 AWG(250.122)

Scenario 230-26Motor Nameplate Information: 208-V 1Ø 2 hp Branch Circuit Supply: 2-pole breaker in a 120/208-V, 3-ph, 4-W panel Refer to Scenario 230-26. The minimum size circuit conductors permitted are ___ AWG. Select one: a. 8 b. 14 c. 12 d. 10 e. 6

14 Refer to Table 430.248 & Table 310.16 13.2x1.25=16.5A or 14 AWG

Motor Nameplate Information: 208-230/460-V 3Ø 3 hp Supply: 3-pole breaker in a 120/208-V, 3-ph, 4-W panel Minimum size circuit conductors are ___ AWG. Select one: a. 12 b. 6 c. 10 d. 8 e. 14

14 Refer to Table 430.250 & Table 310.16 10.6Ax1.25=13.3A or 14 AWG

Using the information shown in Figure 230.224, an ITCB with a maximum permitted rating was installed in the panel. Given this information, the smallest permitted circuit conductors are ___ AWG. Select one: a. 8 b. 12 c. 14 d. 6 e. 10

14 Refer to Tables 430.250, 310.16 14x1.25=17.5A or 14 AWG

Refer to the information shown in Figure 234.152. When the tap for Motor 1 terminates in a breaker enclosure, the maximum permitted size for an ITCB in this enclosure would be ___ A. Select one: a. 15 b. 35 c. 45 d. 25 e. none of these

25 Refer to Tables 430.250,430.52& 240.6(A) Motor 1-9.2A 9.2x2.5=23A R.U 25A

A NEMA Type ___ enclosure provides a degree of protection against windblown dust. Refer to NEC® Table 110.28. Select one: a. 3 b. 1 c. 3R

3

Refer to the information shown in Figure 234.143. The smallest conductors permitted between the gutter and the switch for Motor 3 are ___ AWG. Select one: a. 10 b. 3 c. 4 d. 4/0 e. 8

3 Refer to Table 430.250& 310.16 230/3=76.7A or 4AW FLC-77x1.25=96.25A or 3 AWG

Refer to the nameplate and information shown in Figure 233.241. When this motor tries to start with 3Ø power available, it will pull ___ A. For this motor's Code Letter, use nameplate voltage and the range value that results in the highest current. Select one: a. 332.7 b. 521.1 c. 235.2 d. 576.2 e. 300.8

300.8 Refer to Table 430.251 7.99x15x1000/230x1.732 119,850/398.36=300.8

Motor Nameplate Information: 208-V 1Ø 2 hp Branch Circuit Supply: 2-pole breaker in a 120/208-V, 3-ph, 4-W panel Refer to Scenario 230-26. The maximum size ITCB permitted is ___ A. Select one: a. 20 b. 30 c. 35 d. 40 e. 25

35 Refer to Tables 430.248, 430.52&240.6 13.2x2.5=33 or a 35A breaker

Refer to the nameplate and information shown in Figure 233.241. When this motor is running normally at rated voltage, it is drawing ___ A. Select one: a. 39.2 b. 33.9 c. 46.2 d. 42 e. 45.1

39.2

Refer to the information shown in Figure 234.140. The smallest conductors permitted to be installed from a 120/240-volt, 3Ø, 4-wire panelboard for this motor feeder are ___ AWG or kcmil. Select one: a. 4/0 b. 250 c. 300 d. 3/0 e. 2/0

4/0 Refer to Table 430.250& 310.16 Motor 1-54 Motor 2-104 Motor3-28 104x1.25=130 130+54+28=212 or 4/0 AWG

The nameplate of a 460-volt, three-phase motor shows an FLA of 40 amps. It will draw about ___ amps if one leg is dead when the motor tries to start. This is a fairly typical motor that has a locked-rotor current of about six times the running current. Select one: a. 416 b. 139 c. 378 d. 240 e. 218

416 40x6=240 240x1.732=415.68

Refrigeration equipment requirements are provided in Article ___ in the NEC®. Select one: a. 445 b. 430 c. 460 d. 440 e. 470

440

Article ___ in the NEC® provides requirements for the installation of generators. Select one: a. 470 b. 460 c. 445 d. 440 e. 430

445

The locked-rotor current of a 10 hp, single-phase motor is ___ amps. It operates at 120 volts and the nameplate shows a code letter of F. Select one: a. 559 b. 269 c. 466 d. 600 e. 671

466 Refer to Table 430.7(B) 5.59x10x1,000/120=465.83

Refer to Figure 234.411. The maximum size circuit breaker that you are permitted to use for the branch circuit is ___ amps. Select one: a. 40 b. 35 c. 45 d. 30 e. 50

50

A 240-volt, 3Ø feeder supplies power to four motors. Motor 1 is 50 hp, motor 2 is 40 hp, motor 3 is 30 hp, and motor 4 is 10 hp. The minimum size feeder conductors permitted are ___. Select one: a. 1/0 AWG b. 500 kcmil c. 4/0 AWG d. 250 kcmil e. none of these

500 kcmil Refer to Table 430.250& 310.16 Motor 1-130 Motor 2-104 Motor 3-80 Motor 4-28 130x1.25=162.5 162.5+104+80+25=374.5 or 500 AWG

A three-phase, 240-volt feeder is going to supply power to one 5 hp 3Ø motor, three 2 hp 3Ø motors, and two 1 hp 3Ø motors. The minimum size aluminum THWN/THHN conductors permitted for this feeder are ___ AWG. Select one: a. 2 b. 6 c. 3 d. 8 e. 4

6 Refer to Table 430.250& 310.16 15.2x1.25=19 6.8x3=20.4 4.2x2=8.4 19+20.4+8.4=47.8A or 6AWG

Refer to Figure 230.121. When the maximum permitted size ITCB has been installed for the branch circuit [using 430.52(C)(1) Exc 1] and the smallest permitted circuit conductors are installed, the smallest size EGC permitted is ___ AWG. Select one: a. 8 b. 10 c. 6 d. 14 e. 12

6 Refer to Tables 430.250, 310.16 & 250.122 50Ax1.25=62.5A or 6 AWG(310.16) 50Ax2.5=125A or 6 AWG(250.122)

Scenario 230-27Motor Nameplate Information: 3 hp 208-V 1Ø Branch Circuit Supply: 2-pole breaker in a 120/208-V, 3-ph, 4-W panel Refer to Scenario 230-27. A safety switch is used as the disconnecting means for the motor. The maximum size nontime-delay fuses permitted to be installed are ___ A. Select one: a. 50 b. 60 c. 35 d. 30 e. 45

60 Refer to Tables 430.248, 430.52&240.6 18.7x3=56.1A or a 60A breaker

Motor Nameplate Information: 115/230-V 1Ø 3 hp Supply: 1-pole breaker in a 120/240-V, 1-ph, 3-W panel. The maximum size DETD fuses permitted are ___ A. Select one: a. 40 b. 60 c. 100 d. 70 e. none of these

60 Refer to Tables 430.248, 430.52&240.6 34AX1.75=59.5A or a 60A breaker

A switch with the lowest permitted voltage rating is used for the installation in Figure 230.252. The smallest permitted Square D, NF safety switch has a hp rating of ___. Select one: a. 400 b. 60 c. 30 d. 100 e. 200

60 Refer to Y2 Annex N-10

Refer to the nameplate and information shown in Figure 230.132. The minimum size (standard amp rating) Square D safety switch required to hold DETD fuses has a rating of ___ amps. A switch with the lowest permitted voltage rating is used. Select one: a. 60 b. 200 c. 30 d. 100 e. none of these

60 Refer to Y2 Annex N-12

Motor Nameplate Information: 115/230-V 1Ø 3 HP Supply: 1-pole breaker in a 120/240-V, 3-ph, 4-W panel What minimum size SJ cord is needed to connect this motor? Select one: a. 10 b. 12 c. 7 d. 8 e. 14

7 Refer to Table 430.248 & Table 400.5 Column B 34Ax1.25=42.5A or 7 SJ Cord

Refer to the information shown in Figure 234.152. When the tap for Motor 3 terminates in a breaker enclosure, the maximum permitted size for an ITCB in this enclosure would be ___ A. Select one: a. 35 b. 70 c. 30 d. 60 e. none of these

70 Refer to Tables 430.250,430.52& 240.6(A) Motor 3-26.2A 26.2x2.5=65.5A R.U 70A

AC NAMEPLATE 3: Lennox Industries Model HS26-060-2P Serial 5897F-30976Electrical Ratings: Compressor Fan VOLTS 240 VOLTS 240 PH 1 PH 1Residential RLA 23.9 FLA 1.5Air-Conditioning Unit LRA 32.9 HP 1/4 MCA 32.9 Maximum fuse or circuit breaker 50 Refer to AC NAMEPLATE 3. The minimum size NM Cable Romex® that can be installed to this unit is ___ AWG. Select one: a. 10 b. 6 c. 8 d. 12 e. 4

8

Given the information shown in Figure 230.225 and that the smallest permitted circuit conductors are used, the minimum size EGC permitted is ___ AWG. An ITCB was installed in the panel using 430.52(C)(1) Exc 1. Select one: a. 10 b. 8 c. 14 d. 6 e. 12

8

Motor Nameplate Information: 208-230/460-V 3Ø 25 hp Supply: 3-pole breaker in a 277/480-V, 3-ph, 4-W panel Minimum size circuit conductors are ___ AWG. Select one: a. 6 b. 4 c. 3 d. 8 e. 10

8 Refer to Table 430.250 & Table 310.16 34Ax1.25=42.5A or 8 AWG

Refer to the information shown in Figure 234.143. The smallest conductors permitted between the gutter and the switch for Motor 1 are ___ AWG. Select one: a. 14 b. 4 c. 12 d. 4/0 e. 10 f. 8

8 Refer to Table 430.250& 310.16 250/10=25A or 12 AWG FLC-34x1.25=42.5A or 8 AWG

Refer to Figure 230.261. Between the panel and the wireway, the minimum size circuit conductors for Motor #1 are ___ AWG. Count the number of circuit conductors in the conduit and determine ampacity inside the conduit from the 90º column. Select one: a. 4 b. 12 c. 6 d. 8 e. 10

8 Refer to Table 430.250, 310.15(B)(3)(a)& Table 310.16(90 degree) 28Ax1.25=35A 35/.7=50A or 8 AWG

A 115/230-V, 1Ø, 3 hp motor is fed from a circuit supplied by a 1-pole breaker in a 120/240-V, 1-ph, 3-W panel. The smallest permitted ITCB was installed for this circuit. Utilize 430.52(C)(1) Exc 1. The minimum size EGC permitted is ___ AWG where minimum permitted size circuit conductors are used for this circuit. Select one: a. 10 b. 6 c. 14 d. 8 e. 12

8 Refer to Tables 430.250, 310.16 & 250.122 34Ax1.25=42.5A or 8 AWG(310.16) 34Ax2.5=85A or 4 AWG(250.122)

A 2 hp, 230-volt, three-phase, Design C motor has an FLC of 7 amps, and a LRC of 50 amps. If it is only receiving power from two conductors, the motor will draw ___ amps while starting. Select one: a. 16.7 b. 86.6 c. 42 d. 34.7 e. 72.7

86.6 50x1.732=86.6

The nameplate for a 15 HP, three-phase motor shows an FLA of 18 amps at 460 volts. What minimum size SOO cord is required to connect the motor to the branch circuit? Select one: a. 9 b. 4 c. 8 d. 6 e. 10

9 Refer to Table 430.248 & Table 400.5 Column A 21Ax1.25=26.25A or 9 SOO Cord

Refer to the information shown in Figure 234.152. The maximum permitted rating for an ITCB for the feeder would be ___ A. Select one: a. 100 b. 125 c. 150 d. 90 e. none of these

90 Refer to Table 430.250,430.52& 240.6(A) Motor 1-9.2A Motor 2-14.8A Motor 3-26.2A 26.2x2.5=65.5A R.U 70A 70+9.2+14.8=94A R.D 90A

Refer to the nameplate and information shown in Figure 230.132. The maximum size nontime-delay fuses permitted are ___ A. Select one: a. 90 b. 50 c. 100 d. 70 e. none of these

90 Refer to Tables 430.250, 430.52&240.6 27x3=81A or a 90A breaker

A 50 HP, 480-volt, 3Ø motor has FLA = 53 on its nameplate. The power factor is about 89%. The efficiency of this motor is about ___%. Select one: a. 48.9 b. 52.6 c. 84.7 d. 54.9 e. 60.7 f. 95.1

95.1 Eff=input/output 50x746/53x480x.89x1.732 37,300/39,215.25=.951 .951 or 95.1%

A combination starter consists of a ___. I. disconnect switch II. twist-lock receptacle III. motor starter Select one: a. II and III only b. I & III only c. I only d. I, II, & III e. III only

I & III only disconnect switch & motor starter

Refer to Figure 232.103. ___ could be used as a disconnecting means for a 3-horsepower, 240-volt, single-phase motor. Select one: a. I only b. II only c. Either I or II d. Neither I nor II

I only

Refer to the nameplate shown in Figure 230.123. Drawing ___ at the right shows the correct lead numbering and winding connections for the motor. Select one: a. I only b. II only c. either I or II d. neither I nor II

I only (delta)

The speed of a single-phase AC motor can be easily controlled by changing the ___. I. frequency II.number of poles III. voltage Select one: a. I only b. III only c. I or II only d. II only e. I or II or III

I or II only frequency & number of poles

Among the terminal box (peckerhead) connection drawings shown in Figure 229.213, Diagram ___ is correctly drawn for a 12-lead, wye-wound, dual-voltage motor connected to high (480V) voltage. Select one: a. I b. II c. III d. IV e. none of these

II

The OCPD for a motor branch circuit opens quickly when subjected to faults. These faults include ___. I. overloads II. ground faults III. short circuits Select one: a. I & III only b. I, II & III c. III only d. II only e. I & II only f. II & III only

II & III only ground faults & short circuits

Can a single-pole single-throw (light) switch rated for 277 volts AC only and 20 amps be used as a disconnect for a 1.5 HP, 230-volt, single-phase motor that is stationary? Note: the NEC® considers a toggle switch to be a general-use snap switch. See the definition in Article 100. Select one: a. Yes b. No

No

The starting current of a typical motor is about 6 times the FLA shown ___. Select one: a. in the NEC® b. on the motor nameplate c. either a or b d. neither a nor b

On the motor nameplate.

Motors with built-in thermal protection have field leads labeled with a(n) ___ preceding the lead number. Select one: a. P b. M c. A d. none of these

P

The motor winding leads in Drawing ___ are correctly numbered.

Refer to delta wiring on formula sheet.

When sizing conductors for a 1-phase AC motor, ___ FLA is used. Select one: a. Table 430.249 b. Table 430.250 c. Table 430.248 d. Table 430.247 e. nameplate

Table 430.248

The function of a centrifugal switch in a 1Ø motor is to drop out the start winding when a critical speed is attained. Select one: a. True b. False

True

Refer to the Plan View of the electrical and equipment rooms below. A circuit breaker in Panel HA feeds the starter and the motor in the equipment room. There is a full-height wall between the two rooms. Which of the safety switches must be installed to satisfy the minimum requirements of the NEC®? Select one: a. Y only b. Z only c. Both Y and Z d. Neither Y nor Z

Y only

A ___ motor can be operated from a single-phase AC circuit. Select one: a. capacitor b. synchronous c. split-phase d. series (universal) e. all of these

all of these

A 208-230/460V, delta-wound motor can be supplied with a 3-phase circuit from a ___ service panel. Select one: a. 277/480V, 3Ø, 4W wye b. 120/240V, 3Ø, 4W delta c. 120/208V, 3Ø, 4W wye d. any of these

any of these

The OCPDs protecting circuits for supervised fire pumps are selected to ___. Select one: a. carry LRC for an indefinite period b. permit the pump to burn up before the OCPDs open c. both a & b d. neither a nor b

both a & b

If an overload in a motor branch circuit persists for a long enough period of time, it can cause damage to the ___. Select one: a. insulation on the motor windings b. conductors supplying the motor c. both a and b d. neither a nor b

both a and b

Refer to the motor nameplate shown in Figure 230.110. If you properly connected the single-phase motor but the shaft was rotating in the wrong direction, you would swap the ___. Select one: a. P1 & P2 leads b. P2 & T2 leads c. T2 & T4 leads d. L1 & L2 connections e. none of these

none of these

Refer to the nameplate shown in Figure 230.122. This motor can be supplied power from a ___-connected power supply. I. wye II. delta Select one: a. I only b. II only c. either I or II d. neither I nor II

either I or II

Article 695 covers the installation of ___. Select one: a. jockey pumps b. fire pumps c. both a & b d. neither a nor b

fire pumps

Determine the minimum size feeder conductors required to feed one each 50 hp, 40 hp, 30 hp, and 10 hp motors. Although rated for 208-230/460-volts, 3Ø, each motor will operate at 480-volts. Select one: a. 4/0 AWG b. 250 kcmil c. 2/0 AWG d. 1/0 AWG e. 500 kcmil f. none of these

none of these Refer to Table 430.250& 310.16 Motor 1-65 Motor 2-52 Motor 3-40 Motor 4-14 65x1.25=81.25 81.25+52+40+14=187.25 or 3/0 AWG(none of these)

Refer to Figure 229.302. When operated at 240 volts, the windings of this motor will be connected in ___ with each other. Select one: a. parallel b. series

parallel

The speed of the rotating magnetic field in the stator of an AC motor is referred to as the ___ speed. Select one: a. synchronous b. relative c. actual d. rotor

synchronous

Single-phasing is a term used to describe ___. Select one: a. the process of reversing the direction of a 3Ø motor b. the effect on equipment when one phase of a three-phase circuit is lost c. the calculation required to determine the equivalent size single-phase motor required to replace a three-phase motor d. none of these

the effect on equipment when one phase of a three-phase circuit is lost

Generally, only ___ is authorized to initially energize air-handling and other HVAC equipment. Select one: a. the mechanical contractor b. the MEP engineer c. a journeyman electrician d. none of these

the mechanical contractor