Daddys Quiz Second Part
Part 2 of the quiz.
Questions and Answers
- 1.
At what minimum current lever must a loadbreak tool be used to interupt load with a fused cutout
- A.
15 amps
- B.
20 amps
- C.
60 amps
- D.
5 amps
Correct Answer
A. 15 ampsExplanation
A loadbreak tool is used to interrupt the load in a fused cutout. The minimum current level at which this tool must be used is 15 amps. This suggests that the loadbreak tool is designed to handle loads up to 15 amps and can safely interrupt the flow of current at this level. Using a loadbreak tool with a lower current rating may not be sufficient to safely interrupt the load, while using a tool with a higher current rating would be unnecessary and potentially unsafe.Rate this question:
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- 2.
A customer reports his lights growing bright or dim as he turns on or off other lights what do you look for
- A.
A broken neutral
- B.
A broken connection on cold water liune
- C.
A ground hot leg
- D.
None of the above
Correct Answer
B. A broken connection on cold water liuneExplanation
In this scenario, if a customer reports that their lights grow bright or dim as they turn on or off other lights, the possible cause to look for is a broken connection on the cold water line. This could be causing fluctuations in the electrical system, leading to the inconsistent brightness of the lights. A broken neutral or a ground hot leg may also cause electrical issues, but in this specific case, a broken connection on the cold water line seems to be the most likely cause.Rate this question:
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- 3.
On URD dead front transformers switching is accomplished with the use of what tools
- A.
Elbow puller or shot gun stick
- B.
Rubber gloves
- C.
Load break tool and shot gun
- D.
Work strike with P2 head
Correct Answer
A. Elbow puller or shot gun stickExplanation
On URD dead front transformers, switching is accomplished using either an elbow puller or a shot gun stick. These tools are specifically designed for safely disconnecting and connecting high-voltage cables and components. They provide the necessary insulation and protection for the operator while handling the equipment. Rubber gloves are also essential for ensuring electrical safety, but they are not specifically mentioned as the primary tools for switching on URD dead front transformers. Similarly, a load break tool and shot gun may be used for other purposes but are not explicitly mentioned as the tools for switching on URD dead front transformers. The work strike with P2 head is not relevant to switching on URD dead front transformers.Rate this question:
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- 4.
What determines wire sag?
- A.
Abient temperature
- B.
Span length
- C.
Wire size
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Wire sag is determined by a combination of factors including ambient temperature, span length, and wire size. The ambient temperature affects the expansion and contraction of the wire, causing it to sag more in high temperatures. Span length refers to the distance between the supporting structures, and longer spans result in more sag. Additionally, wire size plays a role as thicker wires have less sag compared to thinner wires. Therefore, all of these factors contribute to determining the amount of sag in a wire.Rate this question:
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- 5.
The correct method to check a compression splice to be certain that adequate pressure has been applied to the sleeve is to.
- A.
Check the number on the disc to be sure the right one was used
- B.
Try to pull the conductor out of the sleeve
- C.
Use compression gauge to check the depth of the indentations
- D.
Check closely to see if there is evidence of cold flow
Correct Answer
C. Use compression gauge to check the depth of the indentationsExplanation
To ensure that adequate pressure has been applied to the sleeve in a compression splice, using a compression gauge to check the depth of the indentations is the correct method. This gauge measures the amount of compression applied to the sleeve and helps determine if it is sufficient. By checking the depth of the indentations, one can verify if the proper pressure has been applied, ensuring a secure and reliable connection.Rate this question:
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- 6.
The term cold flow refers to the tendency
- A.
For random current to flow in a de energized conductor
- B.
For aluminum to flow under pressure
- C.
Of a substance to return to its original form when stress is removed
- D.
Of aluminum to deform when subjected to extreme cold
Correct Answer
B. For aluminum to flow under pressureExplanation
The term "cold flow" refers to the tendency of aluminum to flow under pressure. This means that when aluminum is subjected to pressure, it has the ability to deform and change its shape. This phenomenon is commonly observed in materials like aluminum, where external pressure can cause the material to flow or change its form.Rate this question:
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- 7.
When connecting a copper conductor to an aluminum confuctor it is necessary to place the
- A.
Feed on top regardless of its type
- B.
Conductor side by side
- C.
Copper cnductor above the luminum
- D.
Aluminum conductor above the copper
Correct Answer
D. Aluminum conductor above the copperExplanation
When connecting a copper conductor to an aluminum conductor, it is necessary to place the aluminum conductor above the copper. This is because aluminum and copper have different expansion and contraction rates when exposed to heat. Placing the aluminum conductor above the copper helps to prevent any potential damage or loosening of the connection due to the differential expansion and contraction.Rate this question:
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- 8.
The difference between a 336.4mcm, ascr 18/1 and a 336.4 mcm, ascr 26/7 conductor is that the 336.4 mcm, accsr 26/7 conductor has :
- A.
16 conductors of 7 strands each
- B.
A higher current carrying capacity
- C.
26 strands of steel
- D.
7 strands of steel
Correct Answer
D. 7 strands of steelExplanation
The difference between a 336.4 mcm, ascr 18/1 and a 336.4 mcm, ascr 26/7 conductor is that the 336.4 mcm, ascr 26/7 conductor has 7 strands of steel. This means that the conductor is made up of 26 total strands, with 7 of them being steel strands. The presence of steel strands in the conductor provides additional strength and durability, making it suitable for applications that require higher mechanical strength.Rate this question:
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- 9.
If a single phase watthour meter runs backwards when the service is energized the trouble would be
- A.
Unbalanced 115/230 volt circuits
- B.
Line and load connections reversed
- C.
Leading power factor load
- D.
Hot and neatural connections reversed
Correct Answer
B. Line and load connections reversedExplanation
If a single phase watthour meter runs backwards when the service is energized, the most likely trouble would be that the line and load connections are reversed. This means that the wires that should be connected to the line side of the meter are connected to the load side, and vice versa. This reversal of connections can cause the meter to measure the flow of electricity in the opposite direction, resulting in it running backwards.Rate this question:
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- 10.
The term transposing a transmission line means
- A.
Relocate the entire line
- B.
Change the line voltage
- C.
Change the position of the conductors
- D.
Interchanges the line voltage
Correct Answer
C. Change the position of the conductorsExplanation
Transposing a transmission line refers to changing the position of the conductors. This is done to minimize the effects of electromagnetic interference and maintain balanced voltage levels. By rearranging the position of the conductors, any imbalances in the electromagnetic fields created by the transmission line can be reduced, leading to improved performance and reduced losses. This technique is commonly used in high-voltage transmission lines to ensure efficient and reliable power transmission.Rate this question:
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- 11.
One of the precatuions necessary before releaasing the strain on any pole is to
- A.
Disconnect the power on the line
- B.
Make sure all mechanical load is removed from the pole
- C.
Provide adequate support so the pole wont break
- D.
Make sure the lines are in phasse
Correct Answer
C. Provide adequate support so the pole wont breakExplanation
Before releasing the strain on any pole, it is important to provide adequate support so that the pole won't break. This is necessary because when the strain is released, there may still be some residual tension in the pole, and without proper support, the pole could potentially snap or collapse under the strain. By ensuring that the pole is adequately supported, the risk of damage or injury can be minimized.Rate this question:
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- 12.
The reason why inhibitors are used when splicing conductors is, it
- A.
Prevents oxidation
- B.
Prevents eddy currents
- C.
Improves conductivity
- D.
Increases ductile strength
Correct Answer
A. Prevents oxidationExplanation
Inhibitors are used when splicing conductors to prevent oxidation. Oxidation occurs when the metal in the conductor reacts with oxygen in the air, leading to the formation of a layer of oxide on the surface. This oxide layer can increase resistance and hinder the flow of electricity. By using inhibitors, the oxidation process is slowed down or prevented altogether, ensuring that the conductor maintains its conductivity and efficiency.Rate this question:
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- 13.
Manual switches should always be operated
- A.
Quickly and positivley
- B.
Opened slowly but closed quickly
- C.
Opened quickly but closed slowly
- D.
Slowly and steadily.
Correct Answer
A. Quickly and positivleyExplanation
Manual switches should always be operated quickly and positively to ensure efficient functioning and avoid any delays or errors in the process. Operating the switch quickly ensures a prompt response, while doing so positively ensures that the switch is fully engaged or disengaged without any ambiguity. This approach minimizes the risk of accidental or unintended actions, thereby promoting safety and effectiveness.Rate this question:
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- 14.
When stringing any under ground cable it should not be bent sharper than
- A.
10 times its diameter
- B.
12 times its diameter
- C.
8 times its diameter
- D.
6 times its diameter
Correct Answer
B. 12 times its diameterExplanation
When stringing any underground cable, it is important to avoid bending it too sharply as it can cause damage to the cable. The correct answer is 12 times its diameter, indicating that the cable should not be bent at a radius less than 12 times its diameter. This ensures that the cable remains intact and does not suffer from any structural or functional issues. Bending the cable beyond this limit can result in signal loss, insulation damage, or even breakage, leading to potential disruptions in the transmission of electrical signals.Rate this question:
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- 15.
The maximum allowable PCB content in transformer oil is
- A.
25 ppm
- B.
5 ppm
- C.
75 ppm
- D.
50 ppm
Correct Answer
D. 50 ppmExplanation
The maximum allowable PCB content in transformer oil is 50 ppm. This means that the concentration of Polychlorinated Biphenyls (PCBs) in the oil should not exceed 50 parts per million. PCBs are toxic and persistent pollutants that can have harmful effects on human health and the environment. Therefore, it is important to limit their presence in transformer oil to protect both people and the ecosystem.Rate this question:
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- 16.
When a helicopter is flying a tower to the site, what is likely to build up on the tower
- A.
Ice
- B.
Condensation
- C.
A static charge
- D.
Electromagnetic induction
Correct Answer
C. A static chargeExplanation
When a helicopter is flying close to a tower, it can cause friction between the air and the tower, leading to the accumulation of electrons on the tower's surface. This buildup of electrons creates a static charge on the tower.Rate this question:
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- 17.
When building a line across a railway or highway, who is responsible for traffic control?
- A.
The RCMP
- B.
The municipality
- C.
The department of transportation
- D.
The agency doing work
Correct Answer
D. The agency doing workExplanation
When building a line across a railway or highway, the agency doing the work is responsible for traffic control. This means that the organization or agency undertaking the construction or maintenance work is in charge of managing and directing traffic to ensure the safety of both the workers and the public. They are responsible for implementing necessary traffic control measures such as signage, flaggers, and temporary traffic signals to guide and regulate the flow of vehicles during the construction process.Rate this question:
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- 18.
Which dont you use for a ground connection for personal protective grounds
- A.
System neutral
- B.
Deep driven rod
- C.
Anchor rod
- D.
Temporary rod
Correct Answer
C. Anchor rodExplanation
An anchor rod is not used for a ground connection for personal protective grounds. Anchor rods are typically used to secure structures or equipment to the ground, but they do not provide a reliable path for electrical grounding. In contrast, a system neutral, deep driven rod, or temporary rod can be used for grounding purposes to ensure the safety of individuals and equipment by providing a low resistance path for electrical current to flow into the ground.Rate this question:
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- 19.
When using phasing sticks on a higher voltage you must :
- A.
Add more sections
- B.
Use a larger meter
- C.
Have the sticks tested first
- D.
Use different hooks
Correct Answer
A. Add more sectionsExplanation
When using phasing sticks on a higher voltage, adding more sections to the sticks is necessary. Phasing sticks are used to ensure the proper phasing or synchronization of electrical circuits. As the voltage increases, additional sections need to be added to the phasing sticks to provide sufficient insulation and safety. This helps to prevent electrical accidents and ensures accurate phasing measurements. Using a larger meter or having the sticks tested first may be important for safety and accuracy, but adding more sections is specifically required when dealing with higher voltage. Using different hooks is not mentioned as a requirement in this context.Rate this question:
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- 20.
What is the minimum voltage manufactures use for testing hot sticks?
- A.
35 kv per ft
- B.
50 kv per ft
- C.
100 kv per inch
- D.
100 kv per ft
Correct Answer
D. 100 kv per ftExplanation
Manufacturers use a minimum voltage of 100 kV per foot for testing hot sticks. This high voltage is necessary to ensure the durability and safety of the hot sticks, which are used for working with high voltage electrical equipment. The testing process involves subjecting the hot sticks to this high voltage to check for any potential weaknesses or defects. By using such a high voltage, manufacturers can ensure that the hot sticks are capable of withstanding the extreme conditions they may encounter in real-world applications.Rate this question:
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- 21.
Before entering a manhole that has no ventilation you must
- A.
Hold a tailboard
- B.
Enter the manhole and check for any electrical hazard
- C.
Set up a tripod
- D.
Test for exclosive gases and oxygen
Correct Answer
D. Test for exclosive gases and oxygenExplanation
Before entering a manhole that has no ventilation, it is important to test for explosive gases and oxygen levels. This is crucial for ensuring the safety of the person entering the manhole, as explosive gases can pose a serious risk of fire or explosion. Additionally, low oxygen levels can lead to asphyxiation. By testing for these hazards beforehand, appropriate measures can be taken to mitigate the risks and ensure a safe working environment.Rate this question:
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- 22.
To check leakage current on a bucket truck before starting live line work you would
- A.
Check it with a megger
- B.
Energize the bucket
- C.
Ground the truck
- D.
Ground the boom
Correct Answer
B. Energize the bucketExplanation
Energizing the bucket before starting live line work on a bucket truck allows for the testing of the insulation and leakage current. By energizing the bucket, any potential leakage current can be detected using a megger, which is a device used to measure insulation resistance. This step is crucial for ensuring the safety of the workers and preventing any electrical accidents during live line work. Grounding the truck and the boom are also important safety measures, but they do not specifically address the need to check for leakage current.Rate this question:
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- 23.
When washing a string of energized insulators you would
- A.
The sequence doesnt matter
- B.
Wash from the bottom of the top
- C.
Wash from the center and then down
- D.
Wash from the top to bottom
Correct Answer
B. Wash from the bottom of the topExplanation
When washing a string of energized insulators, it is advisable to wash from the bottom of the top. This is because washing from the bottom ensures that any dirt or debris that is dislodged during the cleaning process does not fall onto the already cleaned lower insulators. By starting from the bottom and working upwards, the cleaning process can be carried out more effectively, ensuring that each insulator is thoroughly cleaned without the risk of recontamination.Rate this question:
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- 24.
The maximum side pull that is allowed on the boom of an RBD is
- A.
00%
- B.
50%
- C.
75%
- D.
25%
Correct Answer
A. 00% -
- 25.
A dangerous condition observed on another utilities systne
- A.
Is nothing to worry about
- B.
Should be reported immediatley to your supervisor or other utility
- C.
None of the above
- D.
Is the utilities problem
Correct Answer
B. Should be reported immediatley to your supervisor or other utilityExplanation
The correct answer is "should be reported immediately to your supervisor or other utility." This means that if a dangerous condition is observed on another utilities system, it is important to inform your supervisor or another utility promptly. This is necessary to ensure that appropriate actions can be taken to address the dangerous condition and prevent any potential harm or accidents.Rate this question:
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- 26.
What should you do with a potential indicator before using it
- A.
Testt it to a known electrical source
- B.
Discharge any static build up
- C.
Test the bulb
- D.
Change the batteries
Correct Answer
D. Change the batteriesExplanation
Before using a potential indicator, it is important to change the batteries. This is because batteries can lose their charge over time, and using a potential indicator with weak or dead batteries can lead to inaccurate readings or the indicator not functioning at all. By changing the batteries, you ensure that the indicator has sufficient power to provide reliable results.Rate this question:
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- 27.
The rotation of a three phase motor is reversed by
- A.
Moving th ebrushes
- B.
Reversing any two line connections
- C.
Reversing the starting windings
- D.
Rotating the bells 90 degrees
Correct Answer
B. Reversing any two line connectionsExplanation
The rotation of a three-phase motor can be reversed by reversing any two line connections. In a three-phase motor, the direction of rotation is determined by the sequence of the three power supply lines. By interchanging any two of these lines, the sequence is changed, resulting in a reversal of the motor's rotation. This is a simple and effective way to change the direction of rotation without needing to modify or adjust any internal components of the motor.Rate this question:
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- 28.
A switch that carries an interupting capacity rating of 100,000 amperes is capable of
- A.
Breaking curcuits where the short circuit campatability of the system is 100,000 amperes or less
- B.
Carrying and switching loads of 100,000 amperes
- C.
Carrying circuits in which surges as high as 100,000 amperes may occur in normal operation
- D.
Carrying test currents as high as 100,000 amperes
Correct Answer
A. Breaking curcuits where the short circuit campatability of the system is 100,000 amperes or lessExplanation
The given correct answer states that a switch with an interrupting capacity rating of 100,000 amperes is capable of breaking circuits where the short circuit compatibility of the system is 100,000 amperes or less. This means that the switch is designed to handle and interrupt currents up to 100,000 amperes, ensuring that it can safely break the circuit in case of a short circuit event. It implies that the switch is specifically rated and suitable for systems with a short circuit capacity of 100,000 amperes or lower, providing protection against excessive current flow.Rate this question:
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- 29.
A convertion from a delta to a wye system should
- A.
Nothing
- B.
Reduce line loses
- C.
Require fewer transformers
- D.
Improve power factor
Correct Answer
B. Reduce line losesExplanation
When converting from a delta to a wye system, the line losses are reduced. This is because in a delta system, the line currents are higher compared to a wye system. Higher currents result in higher resistive losses in the transmission lines. By converting to a wye system, the line currents are reduced, leading to lower resistive losses and ultimately reducing line losses.Rate this question:
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- 30.
The amount of voltage drop in a conductor of a given size depends upon the
- A.
Amount of current flowing in the conductor
- B.
Operating voltage of the system
- C.
Number of strands in the conductor
- D.
Type of insulation used
Correct Answer
A. Amount of current flowing in the conductorExplanation
The amount of voltage drop in a conductor of a given size depends upon the amount of current flowing in the conductor. This is because as current flows through a conductor, it encounters resistance, which leads to a voltage drop. The higher the current flowing through the conductor, the greater the resistance and therefore the greater the voltage drop.Rate this question:
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- 31.
A three wire single phase system when equal loads are connected to the two branches the neutral currect is [assuming both loads operate at unity power factor]
- A.
Half the line current
- B.
Zero
- C.
Twice the line current
- D.
One third the line current
Correct Answer
B. ZeroExplanation
In a three-wire single-phase system, when equal loads are connected to the two branches, the neutral current is zero. This is because the two loads are equal and operate at unity power factor, which means that they consume the same amount of power and have the same current magnitude but with opposite directions. As a result, the currents in the two branches cancel each other out in the neutral wire, resulting in a net current of zero.Rate this question:
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- 32.
A three phase system is so named because
- A.
It operates at 3 x 60 or 180 herts
- B.
Each phase delivers power only 1/3 of the time
- C.
There are three A.C circuits with voltages displaced 120 degrees on the three lines
- D.
Three differnet voltage level exist between three conductors
Correct Answer
C. There are three A.C circuits with voltages displaced 120 degrees on the three linesExplanation
A three-phase system is so named because there are three AC circuits with voltages displaced 120 degrees on the three lines. This means that each line carries a voltage waveform that is 120 degrees out of phase with the other two lines. This arrangement allows for a more efficient and balanced distribution of power compared to a single-phase system. By having multiple phases, the load is evenly distributed across the three lines, resulting in smoother power delivery and reduced power loss.Rate this question:
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- 33.
The reason the neutral conductor must be connected first when installing service conductors is :
- A.
This avoids the possibility of single phase branch circuits being placed in a series across phase conductors
- B.
This eliminates the possibility of a flash when phase conductors are connected
- C.
Static discharges cannot over stress brand circuit insulation and cause the line to ground leckage
- D.
This prevents the ground conductors from carrying current
Correct Answer
A. This avoids the possibility of single phase branch circuits being placed in a series across phase conductorsExplanation
Connecting the neutral conductor first when installing service conductors prevents the possibility of single phase branch circuits being placed in a series across phase conductors. This is important because if branch circuits are connected in series across phase conductors, it can lead to an imbalance in the current flow and potentially cause damage to the electrical system. By connecting the neutral conductor first, it ensures that the phase conductors are properly isolated and reduces the risk of this issue occurring.Rate this question:
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- 34.
Low poer factor in a line may be corrected by adding
- A.
Conductance
- B.
Inductance
- C.
Inductive reactance
- D.
Capacitance
Correct Answer
D. CapacitanceExplanation
Adding capacitance to a line can correct a low power factor because capacitance can help offset the inductive reactance in the line. Inductive reactance causes the current to lag behind the voltage, resulting in a low power factor. By adding capacitance, it introduces a leading current that can balance out the lagging current caused by inductive reactance, thereby improving the power factor.Rate this question:
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- 35.
What test equipment is required to phase and tie together the secondaries of two single phase transformers
- A.
Ammeter
- B.
Voltmeter
- C.
Phase rotation meter
- D.
Ohmmeter
Correct Answer
B. VoltmeterExplanation
To phase and tie together the secondaries of two single phase transformers, a voltmeter is required. This is because a voltmeter is used to measure the voltage between the two secondary windings of the transformers. By measuring the voltage, it is possible to determine the phase relationship between the two transformers and ensure that they are properly synchronized and connected. An ammeter is used to measure current, which is not necessary for this task. A phase rotation meter is used to determine the phase sequence of a three-phase system, so it is not applicable here. An ohmmeter is used to measure resistance, which is also not relevant in this context.Rate this question:
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- 36.
What causes damage to the outside of a conductor?
- A.
Abrasion from hardware and loose tie
- B.
Galloping and vibration
- C.
Lightning and induction
- D.
Static and induction
Correct Answer
B. Galloping and vibrationExplanation
Galloping and vibration can cause damage to the outside of a conductor. Galloping refers to the swaying motion of a conductor caused by wind or other external factors, which can lead to abrasion and wear on the conductor's surface. Vibration, on the other hand, can occur due to various reasons such as mechanical equipment or nearby traffic, and it can cause the conductor to rub against other objects, resulting in damage. Both galloping and vibration pose risks to the integrity of the conductor and can lead to potential failures or faults.Rate this question:
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- 37.
A span of 60.96 meeters has 336 mcm which weifha 386 kgkm. The conductor sag is 1.07m what is the conductor tension?
- A.
5 kg
- B.
25 kg
- C.
50 kg
- D.
200 kg
Correct Answer
D. 200 kgExplanation
The given information states that a span of 60.96 meters has 336 mcm (which is not clear what it means) and weighs 386 kgkm. It also mentions that the conductor sag is 1.07 meters. However, there is no clear formula or equation provided to calculate the conductor tension based on this information. Therefore, an explanation for the given correct answer of 200 kg cannot be generated.Rate this question:
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- 38.
The main purpose of using compound like kearnalex or penetox when splicing aluminum conductors is to
- A.
Increase the tensile strength of the splice
- B.
Prevent galvanic corrosion
- C.
Prevent formation of aluminum oxide
- D.
Reduce effects of cold flow
Correct Answer
C. Prevent formation of aluminum oxideExplanation
When splicing aluminum conductors, the main purpose of using compounds like kearnalex or penetox is to prevent the formation of aluminum oxide. Aluminum oxide is a natural oxide layer that forms on the surface of aluminum when it is exposed to oxygen. This oxide layer can hinder electrical conductivity and increase resistance, leading to poor electrical connections. By using compounds like kearnalex or penetox, which are specifically designed to inhibit the formation of aluminum oxide, the splice can maintain better electrical conductivity and ensure a more reliable connection.Rate this question:
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- 39.
What determines the diameter and the depth of a pole hole
- A.
Type of terrain to be set in
- B.
Conductor size
- C.
Diameter of the butt ang length of the pole
- D.
Type of woof
Correct Answer
C. Diameter of the butt ang length of the poleExplanation
The diameter of the butt and length of the pole determine the diameter and depth of a pole hole. This is because the diameter of the butt determines the size of the hole needed to accommodate the pole, while the length of the pole determines how deep the hole needs to be in order to provide sufficient stability and support for the pole. The other factors mentioned, such as the type of terrain, conductor size, and type of wood, may also have some influence on the dimensions of the hole, but the primary determinants are the diameter of the butt and length of the pole.Rate this question:
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- 40.
When silicia gel is used with transformer it
- A.
Traps any excess oil on the trasnformer
- B.
Removes moisture from the air inside the transformer
- C.
Suppresses any internal arcs cause by the fault in the transformer
- D.
Removes the moisture from the air entering the transformer.
Correct Answer
D. Removes the moisture from the air entering the transformer.Explanation
Silica gel is commonly used as a desiccant, which means it has the ability to absorb moisture from its surroundings. When used with a transformer, silica gel helps to remove moisture from the air entering the transformer. This is important because moisture can cause damage to the transformer and its components. By removing the moisture, silica gel helps to maintain the proper functioning and longevity of the transformer.Rate this question:
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- 41.
When paralelling two distrubution transformer you must ensure that
- A.
That they are both built by the same manufacturer
- B.
The % impendance of the two transformeres are within -/+ 7.5%
- C.
The % impendance of the two transformers are within -/+ 15%
- D.
The KVA ratings are identical
Correct Answer
B. The % impendance of the two transformeres are within -/+ 7.5%Explanation
When paralleling two distribution transformers, it is important to ensure that the % impedance of the two transformers is within -/+ 7.5%. This is because transformers with similar % impedance will have similar voltage regulation characteristics, ensuring that the load is shared evenly between the transformers. If the % impedance is not within this range, there may be an imbalance in the load sharing, leading to unequal voltage regulation and potential damage to the transformers. Therefore, it is crucial to match the % impedance to ensure proper functioning and protection of the transformers.Rate this question:
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- 42.
If a cadweld on a tower leg is bad you will see
- A.
Cold flow
- B.
Flaking paint
- C.
Galvanic corrosion
- D.
Rust around the connection
Correct Answer
C. Galvanic corrosionExplanation
If a cadweld on a tower leg is bad, one would see galvanic corrosion. Galvanic corrosion occurs when two different metals are in contact with an electrolyte, such as moisture or water. In this case, if the cadweld is faulty or deteriorated, it can create a galvanic couple with the tower leg, leading to corrosion. This corrosion would be visible around the connection area and may manifest as rust or discoloration.Rate this question:
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- 43.
What would you do with an infrared heat detector before using it
- A.
Reduse line load
- B.
Test on an object of known temperature
- C.
De energize the line
- D.
Discharge the static build up
Correct Answer
B. Test on an object of known temperatureExplanation
Before using an infrared heat detector, it is important to test it on an object of known temperature. This is necessary to ensure the accuracy and calibration of the detector. By testing it on an object with a known temperature, the user can verify if the detector is providing accurate readings and adjust it if necessary. This step is crucial in obtaining reliable and precise measurements when using an infrared heat detector.Rate this question:
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- 44.
You have a 1000 KVA, 3 phase delta bank, with a primary voltage of 8000 V. What are the size of the primary fuses?
- A.
125 A
- B.
72 A
- C.
1234 A
- D.
1500 A
Correct Answer
B. 72 AExplanation
The correct answer is 72 A because the size of the primary fuses is determined by the transformer's KVA rating. In this case, the transformer is rated at 1000 KVA. According to industry standards, the primary fuses should be sized at 125% of the transformer's rated current. Therefore, 1000 KVA multiplied by 1.25 equals 1250 A. However, the available fuse sizes are limited, so the closest size below 1250 A is 72 A.Rate this question:
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- 45.
What is the adventage of a cluster over a 3 phase transformer?
- A.
Can mantain service if one transformer blows and only need to change the one transformer
- B.
Higher capacity
- C.
Better voltage regulation
- D.
Cheaper
Correct Answer
A. Can mantain service if one transformer blows and only need to change the one transformerExplanation
A cluster of transformers offers the advantage of maintaining service even if one transformer fails. In the event of a blown transformer, only that specific transformer needs to be replaced, while the other transformers in the cluster can continue to provide power. This ensures uninterrupted service and reduces downtime.Rate this question:
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- 46.
If you have a transformer connection that supplies 120/240 V single phase and 240 three phase, what type of connection do you have?
- A.
Crowsfoot (O120/240 - 480/277)
- B.
Open delta (240v or 480v)
- C.
3 phase 4 wire delta (120/240 - 240)
- D.
Undergrounded wye (7500v)
Correct Answer
C. 3 phase 4 wire delta (120/240 - 240)Explanation
The correct answer is 3 phase 4 wire delta (120/240 - 240). This is because the given transformer connection supplies both 120/240 V single phase and 240 V three phase power. The term "3 phase 4 wire delta" refers to a three-phase system with four wires, where the voltage between any two phases is 240 V and the voltage between any phase and the neutral wire is 120 V. The mention of "120/240 - 240" in the answer further confirms this connection type.Rate this question:
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- 47.
If you are given a question on an 8 jaw delta meter, which up till this point you didnt know existed, how would you approach it?
- A.
Panic
- B.
Skip the question
- C.
See if you could determine the answer by tracing out the circuit
- D.
Guess
Correct Answer
C. See if you could determine the answer by tracing out the circuit -
- 48.
When taking voltage reading on a 120/208 volt connection you get readings of 125, 110, 132V. The problem is :
- A.
A bad neutal or ground connection
- B.
An open primary connection
- C.
Two phase are reversed
- D.
There is low voltage being applied to the primary
Correct Answer
A. A bad neutal or ground connectionExplanation
The problem is likely a bad neutral or ground connection. This can cause fluctuations in voltage readings, resulting in inconsistent measurements like the ones mentioned (125, 110, 132V). A faulty neutral or ground connection can disrupt the flow of electricity and lead to improper voltage distribution.Rate this question:
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- 49.
How can the ratio of a window or doughnut CT be changed?
- A.
Run the line through the window again in the same direction
- B.
Reverse the polarity
- C.
It cannot be changed
- D.
Turn the CT around
Correct Answer
A. Run the line through the window again in the same directionExplanation
Running the line through the window again in the same direction can change the ratio of a window or doughnut CT.Rate this question:
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- 50.
What is the purpose of a conservator tank used on large power transformers
- A.
To permit the movement of air into the windings for cooling
- B.
To allow expansion of oil due to heat cycling
- C.
To store water for cooling
- D.
To clean transformer oil
Correct Answer
B. To allow expansion of oil due to heat cyclingExplanation
The purpose of a conservator tank used on large power transformers is to allow expansion of oil due to heat cycling. As the transformer heats up during operation, the oil inside expands and needs extra space to accommodate this expansion. The conservator tank provides this additional space, ensuring that the transformer remains properly filled with oil and preventing any damage or malfunction that could occur if the oil were to overflow or leak.Rate this question:
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