17th Edition Online Practice - Free (2014.1)
A selection of questions taken from the best-selling Electacourse 17th Edition Exam Simulator. Purchased either on its own or as part of the popular Electacourse 17th Edition BS7671 Course, the 17th Edition Exam Simulator has been used by hundreds of UK electricians to pass the City & Guilds 2382-12 Wiring Regulations exam.
- 1.
BS7671 Wiring Regulations do NOT apply to the design, erection and verification of:
- A.
Commercial premises
- B.
Caravans, caravan parks and similar sites
- C.
External lighting and similar installations
- D.
Electric fences covered by BS EN 60335-2-76.
Correct Answer
D. Electric fences covered by BS EN 60335-2-76.Explanation
The BS7671 Wiring Regulations do not apply to the design, erection, and verification of electric fences covered by BS EN 60335-2-76. This means that the specific regulations and guidelines outlined in BS7671 do not need to be followed when installing or working on electric fences that fall under the scope of BS EN 60335-2-76. However, it is important to note that BS7671 still applies to other areas such as commercial premises, caravans and caravan parks, and external lighting installations.Rate this question:
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- 2.
BS7671 Wiring Regulations do NOT apply to the design, erection and verification of:
- A.
Agricultural and horticultural premises
- B.
Highway equipment and street furniture
- C.
Equipment of mobile and fixed offshore installations
- D.
Public premises
Correct Answer
C. Equipment of mobile and fixed offshore installationsExplanation
The BS7671 Wiring Regulations do not apply to the design, erection, and verification of equipment for mobile and fixed offshore installations. These regulations are specific to electrical installations in various premises, including agricultural and horticultural premises, highway equipment and street furniture, and public premises. However, mobile and fixed offshore installations have their own set of regulations and standards that govern their electrical systems, ensuring safety and compliance in these unique environments.Rate this question:
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- 3.
BS7671 Wiring Regulations include requirements for circuits supplied at nominal voltages
- A.
Up to and including 800 V a.c. or 1000 V d.c.
- B.
Up to and including 1000 V a.c. or 1500 V d.c.
- C.
Up to and including 1200 V a.c. or 2000 V d.c.
- D.
Up to and including 100 V a.c. or 150 V d.c.
Correct Answer
B. Up to and including 1000 V a.c. or 1500 V d.c.Explanation
The correct answer is "up to and including 1000 V a.c. or 1500 V d.c." This is because BS7671 Wiring Regulations specify the requirements for circuits supplied at nominal voltages up to and including 1000 V a.c. or 1500 V d.c. This means that the regulations cover electrical installations and wiring systems that operate within these voltage limits.Rate this question:
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- 4.
BS7671 Wiring Regulations may need to be supplemented by the requirements or recommendations of other standards in cases where they are applied to:
- A.
Emergency lighting
- B.
Marinas
- C.
Operating and maintenance gangways.
- D.
Photovoltaic systems
Correct Answer
A. Emergency lightingExplanation
BS7671 Wiring Regulations may need to be supplemented by the requirements or recommendations of other standards in cases where they are applied to emergency lighting. This is because emergency lighting systems have specific requirements and considerations that may not be fully covered by BS7671 alone. These additional standards provide guidance on aspects such as design, installation, and maintenance of emergency lighting systems to ensure their proper functioning during power outages or emergencies. By considering these supplementary standards, the overall safety and effectiveness of emergency lighting systems can be enhanced.Rate this question:
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- 5.
Which of the following is NOT considered as a harmful effect of heat or thermal radiation emitted by electrical equipment?
- A.
Combustion, ignition, or degradation of materials
- B.
Impairment of the safe function of installed equipment
- C.
Risk of bums
- D.
Radioactivity
Correct Answer
D. RadioactivityExplanation
Radioactivity is not considered as a harmful effect of heat or thermal radiation emitted by electrical equipment. Radioactivity refers to the emission of ionizing radiation from unstable atomic nuclei, which is not typically associated with the heat or thermal radiation emitted by electrical equipment. The other options, combustion, ignition, or degradation of materials, impairment of the safe function of installed equipment, and risk of burns, are all potential harmful effects of heat or thermal radiation emitted by electrical equipment.Rate this question:
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- 6.
The fundamental principles of BS7671 state that persons and livestock shall be protected against injury as a consequence of overvoltages originating from
- A.
Motors running
- B.
The operation of circuit breakers
- C.
Atmospheric events
- D.
Voltage recovery
Correct Answer
C. AtmospHeric eventsExplanation
The correct answer is atmospheric events. The fundamental principles of BS7671 state that persons and livestock shall be protected against injury as a consequence of overvoltages originating from atmospheric events. This means that measures should be taken to prevent harm to individuals and animals caused by electrical overvoltages that occur due to lightning strikes, storms, or other atmospheric disturbances.Rate this question:
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- 7.
A single pole switch shall be connected in the
- A.
Earthing conductor only
- B.
Neutral conductor only
- C.
Line conductor only
- D.
Across the neutral and line conductor
Correct Answer
C. Line conductor onlyExplanation
A single pole switch should be connected in the line conductor only. This is because the line conductor is the conductor that carries the current from the power source to the load. By connecting the switch in the line conductor, it allows the flow of current to be controlled, effectively turning the circuit on or off. Connecting the switch in the neutral conductor or the earthing conductor would not serve the purpose of controlling the current flow in the circuit. Connecting the switch across the neutral and line conductor would create a short circuit, which is not the intended function of a switch.Rate this question:
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- 8.
The Regulations do NOT apply to the design, erection and verification of:
- A.
Electrical vehicle charging points
- B.
Photovoltaic systems
- C.
Systems for the distribution of electricity to the public
- D.
Residential premises
Correct Answer
C. Systems for the distribution of electricity to the publicExplanation
The Regulations do not apply to systems for the distribution of electricity to the public. This means that the rules and requirements outlined in the Regulations do not need to be followed when designing, erecting, or verifying such systems. However, it is important to note that the Regulations still apply to other aspects mentioned in the question, such as electrical vehicle charging points, photovoltaic systems, and residential premises.Rate this question:
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- 9.
A device other than current-using equipment, associated with such equipment or with the wiring of an installation is called
- A.
Not current-using equipment
- B.
Accessory
- C.
Supplementary
- D.
Additional equipment
Correct Answer
B. AccessoryExplanation
An accessory is a device that is not current-using equipment but is associated with such equipment or with the wiring of an installation. It serves a supplementary or additional function to the current-using equipment, providing support or enhancing its capabilities.Rate this question:
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- 10.
Extraneous-conductive part is a part liable to introduce a potential, generally Earth potential, and
- A.
Being an earthing part of the electrical installation
- B.
Forming part of the electrical installation
- C.
Is intended to be an earthing part of the electrical installation
- D.
Not forming part of the electrical installation
Correct Answer
D. Not forming part of the electrical installationExplanation
The correct answer is "not forming part of the electrical installation." This means that the extraneous-conductive part is not included or integrated into the electrical installation itself. It is separate from the electrical system and is not intended to be a part of it.Rate this question:
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- 11.
A standard which has been drawn up by common agreement between national standards bodies notified to the European Commission by all member states and published under national procedures is known as
- A.
International Standard
- B.
Conventional Standard
- C.
Harmonized Standard
- D.
Common Standard
Correct Answer
C. Harmonized StandardExplanation
A harmonized standard is a standard that has been agreed upon by national standards bodies of all member states and notified to the European Commission. It is published under national procedures and is aimed at achieving uniformity and compatibility in technical regulations and standards across different countries. Harmonized standards play a crucial role in facilitating trade and ensuring product safety and quality within the European Union.Rate this question:
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- 12.
Heating cable is intended to
- A.
Give off heat for heating purposes
- B.
Be used in heating devices
- C.
Conduct heat for heating purposes
- D.
Supply heat for heating purposes
Correct Answer
A. Give off heat for heating purposesExplanation
The correct answer is "give off heat for heating purposes." Heating cables are designed to produce and emit heat in order to provide warmth for heating purposes. This means that the cables are specifically created to generate heat and release it into the surrounding environment, allowing for effective heating in various applications.Rate this question:
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- 13.
BS7671 IET Wiring Regulations define extra low voltage ripple-free d.c. as not exceeding
- A.
50 volts d.c.
- B.
120 volts d.c.
- C.
150 volts d.c.
- D.
200 volts d.c.
Correct Answer
B. 120 volts d.c.Explanation
The correct answer is 120 volts d.c. According to the BS7671 IET Wiring Regulations, extra low voltage ripple-free d.c. should not exceed 120 volts d.c. This means that any direct current with a voltage higher than 120 volts would not be considered as extra low voltage.Rate this question:
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- 14.
For low voltage equipment, systems and installation, basic protection generally corresponds to protection against
- A.
Mechanical damage
- B.
Circuit overload
- C.
Direct contact
- D.
Risk of burns
Correct Answer
C. Direct contactExplanation
Basic protection for low voltage equipment, systems, and installations generally refers to safeguarding against potential hazards that may arise from direct contact with the equipment. This means implementing measures to prevent individuals from coming into contact with live parts or conductive elements that could cause electric shock or injury. This can involve using insulation, barriers, enclosures, or other protective devices to minimize the risk of direct contact and ensure the safety of individuals interacting with the equipment.Rate this question:
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- 15.
A neutral can be defined as a
- A.
Bus conductor
- B.
Protective conductor
- C.
Live conductor
- D.
Line conductor
Correct Answer
C. Live conductorExplanation
A live conductor refers to a conductor that carries electric current and is not connected to the ground or any other conductor. In electrical systems, live conductors are typically identified by colors such as red or brown. They are responsible for carrying the current from the power source to the load.Rate this question:
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- 16.
A final circuit is defined as the wiring between the
- A.
Distribution board and current-using equipment
- B.
Consumer's main earth terminal and circuit protective device
- C.
Intake and the energy meter
- D.
Main switch and the distribution board
Correct Answer
A. Distribution board and current-using equipmentExplanation
A final circuit refers to the wiring that connects the distribution board to the current-using equipment. This means that it includes the wires that carry electricity from the distribution board to the devices or appliances that consume the electricity. The other options mentioned in the question, such as the consumer's main earth terminal and circuit protective device, intake and energy meter, and main switch and distribution board, are not part of the final circuit.Rate this question:
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- 17.
What is the charging mode of the following statement? Connection of the electric vehicle to the a.c. supply network utilizing an off-board charger where the control pilot function extends to equipment permanently connected to the a.c. supply.
- A.
Mode 1
- B.
Mode 2
- C.
Mode 3
- D.
Mode 4
Correct Answer
D. Mode 4Explanation
The correct answer is Mode 4. Mode 4 is the charging mode where the electric vehicle is connected to an off-board charger that is permanently connected to the AC supply network. In this mode, the control pilot function extends to the equipment connected to the AC supply.Rate this question:
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- 18.
Which of the following should be taken into account in the choice of methods of protection for safety and the selection and erection of equipment?
- A.
It's maximum power
- B.
Its maintainability
- C.
It's suitability for public service
- D.
The country of origin
Correct Answer
B. Its maintainabilityExplanation
When choosing methods of protection for safety and selecting and erecting equipment, it is important to consider its maintainability. This means taking into account how easily the equipment can be maintained, repaired, and serviced. Equipment that is difficult to maintain may lead to increased downtime and higher costs for repairs and replacements. Therefore, considering maintainability ensures that the chosen equipment can be efficiently and effectively maintained, contributing to overall safety and operational effectiveness.Rate this question:
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- 19.
Which of the following does not need to be taken into account in the choice of methods of protection for safety and the selection and erection of equipment?
- A.
Recognized safety services
- B.
Assessment for continuity of service
- C.
The nature of the current and frequency
- D.
The compatibility of its equipment
Correct Answer
C. The nature of the current and frequencyExplanation
In the choice of methods of protection for safety and the selection and erection of equipment, the nature of the current and frequency does not need to be taken into account. The nature of the current refers to whether it is AC (alternating current) or DC (direct current), and the frequency refers to the number of cycles per second in an AC current. While the nature of the current and frequency are important factors to consider in certain electrical applications, they are not directly related to the choice of methods of protection for safety and equipment selection and erection.Rate this question:
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- 20.
Which of the following does not need to be taken into account in the choice of methods of protection for safety and the selection and erection of equipment?
- A.
The external influences to which it is to be exposed
- B.
Its maintainability
- C.
Recognized safety services
- D.
It's suitability for public service
Correct Answer
D. It's suitability for public serviceExplanation
The suitability for public service does not need to be taken into account in the choice of methods of protection for safety and the selection and erection of equipment. The focus should be on external influences, maintainability, and recognized safety services to ensure the safety and functionality of the equipment. The suitability for public service may be a consideration in other aspects, but not specifically in the choice of protection methods and equipment selection.Rate this question:
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- 21.
The third letter of the code for system earthing type has a meaning of
- A.
Relationship of the exposed-conductive-parts of the installation to Earth
- B.
Relationship of the exposed-conductive-parts of the installation to the power system
- C.
Relationship of the power system to Earth
- D.
Arrangement of neutral and protective conductors
Correct Answer
D. Arrangement of neutral and protective conductorsExplanation
The third letter of the code for system earthing type refers to the arrangement of neutral and protective conductors. This means that the code indicates how the neutral and protective conductors are arranged in the electrical installation. The arrangement of these conductors is important for ensuring the safety and proper functioning of the electrical system.Rate this question:
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- 22.
In each installation main protective bonding conductors shall connect to the main earthing terminal extraneous-conductive-parts including:
- A.
Multimedia network system cables
- B.
Power supply
- C.
Metal fences
- D.
Exposed metallic structural parts of the building.
Correct Answer
D. Exposed metallic structural parts of the building.Explanation
The main protective bonding conductors in each installation need to connect to the main earthing terminal. This includes connecting to extraneous-conductive parts such as multimedia network system cables, power supply, metal fences, and exposed metallic structural parts of the building.Rate this question:
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- 23.
According to the Regulations a protective measure shall consist of
- A.
A provision for basic protection and an independent provision for fault protection
- B.
An enhanced protective provision which provides both basic protection and fault protection.
- C.
An independent provision for basic protection and an enhanced protective provision for fault protection
- D.
An appropriate combination of a provision for basic protection and an independent provision for fault protection or an enhanced protective provision which provides both basic protection and fault protection.
Correct Answer
D. An appropriate combination of a provision for basic protection and an independent provision for fault protection or an enhanced protective provision which provides both basic protection and fault protection.Explanation
The correct answer is an appropriate combination of a provision for basic protection and an independent provision for fault protection or an enhanced protective provision which provides both basic protection and fault protection. This means that a protective measure can either consist of a separate provision for basic protection and fault protection, or it can be an enhanced provision that includes both basic and fault protection. The regulations allow for flexibility in the design of protective measures, as long as they provide the necessary level of protection.Rate this question:
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- 24.
If an RCD is used in a TN-C-S system, which conductor shall not be used on the load side?
- A.
PEN conductor
- B.
Protective conductor
- C.
Neutral conductor
- D.
Line conductor
Correct Answer
A. PEN conductorExplanation
In a TN-C-S system, the PEN conductor is used as a combined protective and neutral conductor. However, when an RCD (Residual Current Device) is used, it is important not to use the PEN conductor on the load side. This is because the RCD measures the imbalance between the line and neutral currents, and if the PEN conductor is used on the load side, it can create a false imbalance and cause the RCD to trip unnecessarily. Therefore, the PEN conductor should not be used on the load side when an RCD is present.Rate this question:
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- 25.
Except for equipment for which an appropriate product standard specifies requirements a luminaire shall be kept at an adequate distance from combustible materials. Unless otherwise recommended by the manufacturer, a small spotlight or projector rated up to 100 W shall be installed at the following minimum distance from combustible materials:
- A.
0.3 m
- B.
0.4 m
- C.
0.5 m
- D.
0.7 m
Correct Answer
C. 0.5 mExplanation
A luminaire is required to be kept at an adequate distance from combustible materials, unless there is a specific product standard that specifies the requirements for the equipment. For a small spotlight or projector rated up to 100 W, the minimum recommended distance from combustible materials is 0.5 m. This distance helps to ensure that the heat generated by the spotlight or projector does not pose a fire hazard to the combustible materials.Rate this question:
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- 26.
A TN or TT wiring system, other than mineral insulated cable, busbar trunking system or power track system shall be protected against insulation faults by an RCD having a rated residual operating current not exceeding
- A.
50 mA
- B.
100 mA
- C.
200 mA
- D.
300 mA
Correct Answer
D. 300 mAExplanation
The correct answer is 300 mA. In a TN or TT wiring system, an RCD (Residual Current Device) is used to protect against insulation faults. The RCD is designed to detect any imbalance in the electrical current flowing through the system, which could indicate a fault or leakage to earth. The rated residual operating current of the RCD determines the level of imbalance that will trigger it to trip and disconnect the power. In this case, the RCD should have a rated residual operating current not exceeding 300 mA, meaning it will trip if the current imbalance exceeds 300 mA.Rate this question:
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- 27.
Regardless of the nominal voltage of a circuit supplied at extra-low voltage, live parts shall be either contained in enclosures affording a degree of protection of at least IPXXB or IP2X, or provided with insulation capable of
- A.
Withstanding a test voltage of 100 V d.c. for 2 minutes.
- B.
Withstanding a test voltage of 300 V d.c. for 1 minute.
- C.
Withstanding a test voltage of 500 V d.c. for 2 minutes.
- D.
Withstanding a test voltage of 500 V d.c. for 1 minute.
Correct Answer
D. Withstanding a test voltage of 500 V d.c. for 1 minute.Explanation
Live parts in a circuit supplied at extra-low voltage must have a certain level of protection or insulation. The correct answer states that the live parts should be able to withstand a test voltage of 500 V d.c. for 1 minute. This means that the insulation or protection must be able to handle this voltage for the specified duration. This requirement ensures the safety of individuals working with or around the circuit, as it ensures that the live parts are adequately protected and can withstand higher voltages without causing harm.Rate this question:
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- 28.
For protection against burns the temperature limit under normal load conditions for a hand-held part with non-metallic surface is
- A.
50 ¡C
- B.
55 ¡C
- C.
60 ¡C
- D.
65 ¡C
Correct Answer
D. 65 ¡CExplanation
The correct answer is 65 °C. This temperature limit is set to ensure protection against burns when handling a hand-held part with a non-metallic surface. It indicates that the surface can safely withstand temperatures up to 65 °C under normal load conditions without causing burns or discomfort to the person handling it.Rate this question:
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- 29.
For protection against burns the temperature limit under normal load conditions for a part which need not be touched with metallic surface is
- A.
70 C
- B.
80 C
- C.
90 C
- D.
100 C
Correct Answer
B. 80 CExplanation
The correct answer is 80 C. This temperature limit is set to ensure protection against burns when handling a part that does not need to be touched with a metallic surface. It indicates that the part can withstand temperatures up to 80 degrees Celsius without causing harm or injury due to heat.Rate this question:
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- 30.
For an installation with nominal voltage 400/690 V the required minimum impulse withstand voltage of category III overvoltage protective device (equipment with high impulse voltage) is
- A.
2.5 kV
- B.
4 kV
- C.
6 kV
- D.
8 kV
Correct Answer
C. 6 kVExplanation
In an installation with a nominal voltage of 400/690 V, the required minimum impulse withstand voltage of category III overvoltage protective device (equipment with high impulse voltage) is 6 kV. This means that the protective device must be able to withstand a voltage surge of up to 6 kV without being damaged. This is important to ensure the safety and proper functioning of the electrical installation, as it protects against voltage spikes and surges that can occur due to lightning strikes or other electrical disturbances.Rate this question:
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- 31.
Equipotential copper bonding designed as a bonding ring network must have a minimum round diameter of
- A.
8 mm
- B.
10 mm
- C.
12 mm
- D.
15 mm
Correct Answer
A. 8 mmExplanation
The minimum round diameter of an equipotential copper bonding designed as a bonding ring network is 8 mm. This means that the diameter of the bonding ring should be at least 8 mm in order to ensure effective bonding and equalization of electrical potential between different points in the network. A larger diameter would provide even better bonding, but the minimum requirement is 8 mm.Rate this question:
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- 32.
The maximum disconnection time for a 400v a.c. final circuit with a TN supply is
- A.
5s
- B.
0.2s
- C.
0.5s
- D.
5ms
Correct Answer
B. 0.2sExplanation
The maximum disconnection time for a 400v a.c. final circuit with a TN supply is 0.2s. This means that in the event of a fault or overload, the circuit will be disconnected within 0.2 seconds to ensure safety and prevent any potential damage or harm.Rate this question:
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- 33.
The maximum disconnection time for a 230v a.c. circuit with a TN supply is
- A.
3S
- B.
0.2S
- C.
0.4MS
- D.
5S
Correct Answer
D. 5SExplanation
The correct answer is 5S. In a TN supply system, the maximum disconnection time for a 230V AC circuit is determined by safety regulations. This time is set to ensure that in the event of a fault or electrical hazard, the circuit is disconnected quickly enough to prevent harm to individuals or damage to equipment. A disconnection time of 5 seconds allows for a swift response to potential dangers, minimizing the risk of injury or accidents.Rate this question:
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- 34.
In the diagram below, a ring final circuit is wired in high impact PVC conduit. The number of single core cables installed in section A to B will be
- A.
2
- B.
3
- C.
5
- D.
6
Correct Answer
D. 6Explanation
The number of single core cables installed in section A to B will be 6. This can be determined by counting the number of cables shown in the diagram between section A and B.Rate this question:
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- 35.
At the origin of an electrical installation, the prospective fault current must be taken into account when
- A.
Selecting the type of overcurrent device to be installed
- B.
Applying diversity to the installation
- C.
Assessing the earthing arrangement
- D.
Estimating the external fault loop impedance
Correct Answer
A. Selecting the type of overcurrent device to be installedExplanation
When selecting the type of overcurrent device to be installed in an electrical installation, the prospective fault current must be taken into account. This is because the overcurrent device needs to be able to handle the maximum fault current that could occur in the system. If the fault current exceeds the rating of the overcurrent device, it may not be able to effectively protect the installation from short circuits or overloads. Therefore, considering the prospective fault current is crucial in ensuring the proper functioning and safety of the electrical system.Rate this question:
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- 36.
Protective measures against electric shock can be achieved by automatic disconnection of the supply and in a.c. systems additional protection by means of an rcd shall be provided for
- A.
Socket outlets with a rated current exceeding 20 A
- B.
Socket outlets with a rated current not exceeding 13 A
- C.
Mobile equipment with a current rating not exceeding 32 A
- D.
Mobile equipment with a current rating exceeding 32 A
Correct Answer
C. Mobile equipment with a current rating not exceeding 32 A -
- 37.
An overcurrent protective device installed at the origin of a circuit must have a breaking capacity of
- A.
At least 15kA
- B.
Equivalent or more than the prospective short circuit current
- C.
Twice the prospective short circuit current
- D.
Equivalent to maximum earth fault current
Correct Answer
B. Equivalent or more than the prospective short circuit currentExplanation
The overcurrent protective device installed at the origin of a circuit must have a breaking capacity equivalent or more than the prospective short circuit current because it needs to be able to safely interrupt the flow of current in the event of a short circuit. If the breaking capacity is lower than the prospective short circuit current, the device may not be able to interrupt the fault current effectively, leading to potential damage to the circuit and equipment, as well as safety hazards. Therefore, it is crucial to have a breaking capacity that is equivalent or higher than the prospective short circuit current to ensure proper protection.Rate this question:
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- 38.
What class of external influence for the purpose of the Regulations is conventionally regarded as normal for atmospheric humidity?
- A.
AB2
- B.
AB3
- C.
AB4
- D.
AB5
Correct Answer
C. AB4Explanation
AB4 is the correct answer because it refers to the class of external influence that is conventionally regarded as normal for atmospheric humidity. This suggests that AB4 represents the standard or typical level of atmospheric humidity that is considered normal in the context of the Regulations. The other options (AB2, AB3, and AB5) are not specifically mentioned as being normal or conventionally regarded as such, making AB4 the most appropriate choice.Rate this question:
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- 39.
According to the regulations, cores of cables shall be identified by
- A.
Colour
- B.
Lettering
- C.
Numbering
- D.
Colour and/or lettering and/or numbering
Correct Answer
D. Colour and/or lettering and/or numberingExplanation
According to the regulations, the cores of cables can be identified using either colour, lettering, numbering, or a combination of these methods. This means that cables can be marked with a specific colour, a letter code, a number code, or a combination of these options to distinguish the different cores within the cable. This flexibility allows for different identification systems to be used based on the specific requirements and standards in place.Rate this question:
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- 40.
Green-and-yellow with blue markings at the terminations or blue with green-and-yellow at the terminations colouring is to be used for
- A.
PEN conductor
- B.
Line conductor
- C.
Neutral or midpoint conductor
- D.
Protective conductor
Correct Answer
A. PEN conductorExplanation
The green-and-yellow with blue markings at the terminations or blue with green-and-yellow at the terminations coloring is used for the PEN conductor. The PEN conductor, also known as the combined protective, neutral, and earth conductor, is used in electrical systems to provide a return path for fault currents and to protect against electrical faults. The specific coloring helps identify and differentiate the PEN conductor from other conductors in the system.Rate this question:
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- 41.
If an installation includes alternative or additional sources of supply, at what location(s) does a warning notice NOT need to be affixed in the installation?
- A.
At the origin of the installation
- B.
At the meter position, if remote from the origin
- C.
At the consumer unit or distribution board to which the alternative or additional sources are connected
- D.
At the points of earthing
Correct Answer
D. At the points of earthingExplanation
A warning notice does not need to be affixed at the points of earthing in the installation because the purpose of a warning notice is to alert individuals to potential hazards or risks associated with the installation. The points of earthing are typically where the electrical system is grounded, and there are usually no hazards or risks associated with these points that would require a warning notice. Therefore, it is not necessary to have a warning notice at the points of earthing.Rate this question:
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- 42.
Equipment that is intended to be moved in use shall be connected by
- A.
Non-flexible cables.
- B.
Flexible cables, except equipment supplied by contact rails.
- C.
Either non-flexible or flexible cables.
- D.
Contact rails.
Correct Answer
B. Flexible cables, except equipment supplied by contact rails.Explanation
Equipment that is intended to be moved in use should be connected by flexible cables, except for equipment that is supplied by contact rails. This means that most equipment that needs to be moved while in use should be connected using flexible cables, which can withstand the movement and bending. However, equipment that is specifically designed to be supplied by contact rails, such as certain types of machinery or vehicles, may use non-flexible cables instead.Rate this question:
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- 43.
What is considered an ambient temperature for a cable?
- A.
The temperature of the surrounding medium when the non-sheathed or sheathed cable(s) under consideration are not loaded.
- B.
The temperature of the surrounding medium when the non-sheathed or sheathed cable(s) under consideration are loaded.
- C.
The temperature of the cable's surface when the non-sheathed or sheathed cable(s) under consideration are not loaded.
- D.
The temperature of the cable's surface when the non-sheathed or sheathed cable(s) under consideration are loaded.
Correct Answer
A. The temperature of the surrounding medium when the non-sheathed or sheathed cable(s) under consideration are not loaded.Explanation
The ambient temperature for a cable refers to the temperature of the surrounding medium when the cable is not being used or loaded. This means that it is the temperature of the environment in which the cable is installed, but without any additional heat generated by the cable itself. This is important to consider because the temperature of the surrounding medium can affect the performance and lifespan of the cable.Rate this question:
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- 44.
In the event of crossing or proximity of underground telecommunication cables and underground power cables, what is a minimum clearance to be maintained between them?
- A.
80 mm
- B.
100 mm
- C.
120 mm
- D.
150 mm
Correct Answer
B. 100 mmExplanation
In the event of crossing or proximity of underground telecommunication cables and underground power cables, a minimum clearance of 100 mm should be maintained between them. This clearance is necessary to prevent any interference or damage to the cables and ensure the safety and proper functioning of both the telecommunication and power systems.Rate this question:
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- 45.
SPD stands for
- A.
Special protective device
- B.
Surge protective device
- C.
Switching protective device
- D.
Supplementary protective device
Correct Answer
B. Surge protective deviceExplanation
SPD stands for surge protective device. Surge protective devices are electrical devices designed to protect electrical equipment from voltage spikes and surges. They divert excess voltage away from sensitive equipment, preventing damage and ensuring the smooth operation of electrical systems. Surge protective devices are commonly used in homes, offices, and industrial settings to safeguard electronic devices and appliances from power surges caused by lightning strikes, power grid fluctuations, or other electrical disturbances.Rate this question:
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- 46.
LPZ stands for
- A.
Limited protection zone
- B.
Luminaire protection zone
- C.
Lightning protection zone
- D.
Line protection zone
Correct Answer
C. Lightning protection zoneExplanation
LPZ stands for lightning protection zone. This term refers to an area or zone where specific measures are taken to protect a structure or equipment from the damaging effects of lightning strikes. These measures may include the installation of lightning rods, surge protectors, and grounding systems to safely dissipate the electrical energy caused by lightning strikes. The purpose of creating a lightning protection zone is to minimize the risk of fire, structural damage, and electrical damage that can result from lightning strikes.Rate this question:
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- 47.
Concerning critical length of conductors connecting SPD to a circuit, The total lead length should
- A.
Not exceed 0.5 m
- B.
Not exceed 1.0 m
- C.
Preferably not exceed 0.5 m, but shall in no case exceed 1.0 m
- D.
Preferably not exceed 1.0 m
Correct Answer
C. Preferably not exceed 0.5 m, but shall in no case exceed 1.0 mExplanation
The correct answer is "preferably not exceed 0.5 m, but shall in no case exceed 1.0 m." This means that the ideal length for the conductors connecting the SPD to a circuit is less than or equal to 0.5 m. However, if it is not possible to keep the length within this limit, it should not exceed 1.0 m under any circumstances.Rate this question:
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- 48.
Minimum cross-sectional area of a steel buried earthing conductor without corrosion/damage protection is
- A.
50 mm2
- B.
35 mm2
- C.
25 mm2
- D.
10 mm2
Correct Answer
A. 50 mm2Explanation
The minimum cross-sectional area of a steel buried earthing conductor without corrosion/damage protection is 50 mm2. This is because a larger cross-sectional area provides better conductivity and reduces the resistance of the conductor. A lower resistance ensures that the earthing system can effectively dissipate fault currents and protect against electrical hazards. Therefore, a larger cross-sectional area, in this case, 50 mm2, is necessary to ensure the proper functioning of the earthing conductor.Rate this question:
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- 49.
Which one can serve as a part of a protective conductor?
- A.
An oil pipe
- B.
A flexible or pliable conduit
- C.
A conductor in a cable
- D.
A gas pipe
Correct Answer
C. A conductor in a cableExplanation
A conductor in a cable can serve as a part of a protective conductor because it is designed to carry electrical current and provide a low resistance path for fault currents to flow. In the event of a fault or electrical leakage, the protective conductor helps to divert the current away from the user or equipment, preventing electric shock or damage. It is an essential component in ensuring electrical safety and grounding systems.Rate this question:
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- 50.
Which system a step-up autotransformer shall not be connected to?
- A.
TT
- B.
IT
- C.
TN
- D.
TN and TT
Correct Answer
B. ITExplanation
An autotransformer is a type of transformer that uses a single winding to step up or step down the voltage. When connecting a step-up autotransformer, it should not be connected to the IT (Isolated or Insulated Transformer) system. The IT system is a type of electrical system where the neutral point is not connected to the earth or ground. Connecting a step-up autotransformer to an IT system can cause a fault condition known as an insulation fault, which can be hazardous and can lead to electric shock or damage to equipment.Rate this question:
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Current Version
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Mar 15, 2023Quiz Edited by
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Jun 04, 2014Quiz Created by
Julian