FREE AND STUDY GAMES ABOUT CODEOLOGY 6 EXAM

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FREE AND STUDY GAMES ABOUT CODEOLOGY 6 EXAM

QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -20 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: 18.Size the maximum primary and secondary overcurrent devices for a

100-kilovolt-amperes, 3-phase transformer, a 480-volt primary, and a 208/120 volts secondary (Only consider the transformer and not conductor protection or panelboard protection).a.

Answer:

• 300 A (primary) / 350 A (secondary)

Question 2: 12.According to 430.32, if a continuous-duty motor nameplate does not have a 1.15 or greater service factor or temperature rise of 40°C or less, then a separate overload protection device must be set at no more than ? (assuming that this selection wil

Answer:

• 115%

Question 3: 14.Using 430.52 and Table 430.248, what is the maximum size dual-element fuse short-circuit and ground-fault protective device allowed for a 10-horsepower, 230-volt, single-phase motor, assuming the motor starts with this size?

• 50 A
• 70 A
• 8

Answer:

• 90 A Correct

Note: 50 × 1.75 = 87.5 A

430.52(C)(1) Exception 1 allows rounding-up to next size standard fuse. 87.5 = 90 ampere fuse.

The correct answer is: 90 A

Question 4: When an AC motor is started across the line, a high inrush current occurs.

Answer:

True Question 5: 20.Overcurrent protection is required in each ungrounded conductor supplying a capacitor. The conductor ampacity shall not be less than ? of the rated current of the capacitor.

• 100%
• 125%
• 135%Correct
• 150%

Answer:

• 135%

The correct answer is: 460.8

Question 6: Which of the following is typically true regarding motor overcurrent protection?

• Motor branch-circuit short-circuit and ground-fault protection is located at the beginning of a

motor branch circuit in order to provide short-circuit and ground-fault

Answer:

• Both I. and II.

Question 7: 15.Using Table 430.52, what is the maximum instantaneous trip circuit breaker setting allowed for the motor installation using a 460-volt, 25-horsepower, 3-phase motor marked with a 115% service factor and a nameplate current of 32 amperes based upon 430.

Answer:

272 A

Note: 34 × 800% = 272 A

The circuit breaker in this question is an instantaneous trip only circuit breaker which does not have an overload sensing element. Do not confuse this with a thermal magnetic circuit breaker. This result is the setting of Question 8: In some cases, momentary high inrush currents during motor starting can reach as high as ? times the normal running current amperes during the first 1/2 cycle.

Select one:

• 2
• 4
• 10
• 20

Answer:

• 20

Question 9: In addition to determining the proper OCPD ampere rating for an application, what criteria is/are important when selecting overcurrent devices?

Select one:

• Interrupting rating
• Short-circuit current ratings
• Voltage rating
• All of the abov

Answer:

• All of the above

Question 10: 9.Separate motor and branch-circuit overload protection is sized based upon the ?

• Full load current based on motor horsepower in NEC Tables 430.247 to 430.250
• maximum locked-rotor current
• motor nameplate full-load current
• start-up curr

Answer:

motor nameplate full-load current Question 11: 16. Instantaneous trip circuit breakers are also referred to as motor circuit protectors (MCPs) and are intended only for motor branch circuit short-circuit and ground-fault protection.True False

Answer:

True Question 12: 11. Using the conductor sizing guide in this lesson, what conductor ampacity is needed for a 10-horsepower, 230-volt single phase motor?

Answer:

• 62.5 A Correct

Note: Motor ampacity from Table 430.248: 50 A

Minimum conductor ampacity calculated = 50 × 1.25 = 62.5 A using Conductor Ampacity Selection Guide 6, 7, 8.

The correct answer is: 62.5 A

Question 13: Most circuit breakers and fuses would "nuisance open" on motor startup if sized to provide motor and branch-circuit overload protection. As a result, motor branch circuits are permitted by NEC requirements to have two separate overcurrent protective devic

Answer:

Tue