17th Edition Online Practice - Free (2014.1)

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  • 1/83 Questions

    Floor and heating systems shall use a RCD as a means of automatic disconnection of supply with a current rating of

    • 20mA
    • 120mA
    • 30mA
    • 10mA
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17th Edition Online Practice - Free (2014.1) - Quiz
About This Quiz

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.

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  • 2. 

    Equipment that is intended to be moved in use shall be connected by

    • Non-flexible cables.

    • Flexible cables, except equipment supplied by contact rails.

    • Either non-flexible or flexible cables.

    • Contact rails.

    Correct Answer
    A. 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.

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  • 3. 

    BS7671 Wiring Regulations do NOT apply to the design, erection and verification of:

    • Commercial premises

    • Caravans, caravan parks and similar sites

    • External lighting and similar installations

    • Electric fences covered by BS EN 60335-2-76.

    Correct Answer
    A. 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.

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  • 4. 

    A final circuit is defined as the wiring between the

    • Distribution board and current-using equipment

    • Consumer's main earth terminal and circuit protective device

    • Intake and the energy meter

    • Main switch and the distribution board

    Correct Answer
    A. Distribution board and current-using equipment
    Explanation
    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.

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  • 5. 

    A copy of the distribution board schedule shall be located with

    • The local REC

    • Building control

    • The installation contractor

    • The distribution board

    Correct Answer
    A. The distribution board
    Explanation
    The copy of the distribution board schedule should be located with the distribution board itself. This ensures that the schedule is easily accessible and readily available for reference whenever needed. Storing the schedule with the distribution board also helps in maintaining organization and streamlining the process of managing and maintaining the electrical system.

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  • 6. 

    What is the minimum IP classification code for an EV charging point installed outdoors?

    • IP11

    • IP14

    • IP41

    • IP44

    Correct Answer
    A. IP44
    Explanation
    The minimum IP classification code for an EV charging point installed outdoors is IP44. This code indicates that the charging point is protected against solid objects larger than 1mm and protected against water splashing from any direction. This level of protection is necessary to ensure the safety and durability of the charging point in outdoor environments.

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  • 7. 

    A single pole switch shall be connected in the

    • Earthing conductor only

    • Neutral conductor only

    • Line conductor only

    • Across the neutral and line conductor

    Correct Answer
    A. Line conductor only
    Explanation
    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.

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  • 8. 

    In each installation main protective bonding conductors shall connect to the main earthing terminal extraneous-conductive-parts including:

    • Multimedia network system cables

    • Power supply

    • Metal fences

    • Exposed metallic structural parts of the building.

    Correct Answer
    A. 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.

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  • 9. 

    SPD stands for

    • Special protective device

    • Surge protective device

    • Switching protective device

    • Supplementary protective device

    Correct Answer
    A. Surge protective device
    Explanation
    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.

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  • 10. 

    Which one can serve as a part of a protective conductor?

    • An oil pipe

    • A flexible or pliable conduit

    • A conductor in a cable

    • A gas pipe

    Correct Answer
    A. A conductor in a cable
    Explanation
    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.

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  • 11. 

    BS7671 Wiring Regulations do NOT apply to the design, erection and verification of:

    • Agricultural and horticultural premises

    • Highway equipment and street furniture

    • Equipment of mobile and fixed offshore installations

    • Public premises

    Correct Answer
    A. Equipment of mobile and fixed offshore installations
    Explanation
    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.

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  • 12. 

    BS7671 Wiring Regulations include requirements for circuits supplied at nominal voltages

    • Up to and including 800 V a.c. or 1000 V d.c.

    • Up to and including 1000 V a.c. or 1500 V d.c.

    • Up to and including 1200 V a.c. or 2000 V d.c.

    • Up to and including 100 V a.c. or 150 V d.c.

    Correct Answer
    A. 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.

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  • 13. 

    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

    • 2

    • 3

    • 5

    • 6

    Correct Answer
    A. 6
    Explanation
    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.

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  • 14. 

    BS 5839 refers specifically to

    • Thermal insulation

    • Emergency lighting

    • Bayonet lamp holders

    • Fire detection and alarm systems for buildings

    Correct Answer
    A. Fire detection and alarm systems for buildings
    Explanation
    BS 5839 is a British Standard that provides guidelines for the design, installation, commissioning, and maintenance of fire detection and alarm systems in buildings. It covers various aspects such as the types of fire detection systems, the positioning of fire detectors, the requirements for alarm systems, and the necessary maintenance procedures. Therefore, the correct answer is fire detection and alarm systems for buildings.

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  • 15. 

    The Regulations do NOT apply to the design, erection and verification of:

    • Electrical vehicle charging points

    • Photovoltaic systems

    • Systems for the distribution of electricity to the public

    • Residential premises

    Correct Answer
    A. Systems for the distribution of electricity to the public
    Explanation
    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.

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  • 16. 

    Which protective measure in a floor and ceiling heating system is not permitted?

    • Double or reinforced isolation

    • Protection by an RCD

    • Earth-free local equipotential bonding

    • Automatic disconnection of supply

    Correct Answer
    A. Earth-free local equipotential bonding
    Explanation
    Earth-free local equipotential bonding is not permitted in a floor and ceiling heating system. This measure involves connecting all metallic parts in the system to a common earth point, which helps to prevent electric shock hazards. However, in a floor and ceiling heating system, this bonding is not allowed because it can interfere with the proper functioning of the system and cause electrical faults. Therefore, it is important to avoid using earth-free local equipotential bonding in such systems.

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  • 17. 

    According to the regulations, cores of cables shall be identified by

    • Colour

    • Lettering

    • Numbering

    • Colour and/or lettering and/or numbering

    Correct Answer
    A. Colour and/or lettering and/or numbering
    Explanation
    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.

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  • 18. 

    Green-and-yellow with blue markings at the terminations or blue with green-and-yellow at the terminations colouring is to be used for

    • PEN conductor

    • Line conductor

    • Neutral or midpoint conductor

    • Protective conductor

    Correct Answer
    A. PEN conductor
    Explanation
    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.

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  • 19. 

    On a residual current device, the purpose of the integral test button is to check

    • The mechanical function

    • The electrical function

    • The rating

    • The disconnection time

    Correct Answer
    A. The mechanical function
    Explanation
    The integral test button on a residual current device is used to check the mechanical function. This means that when the button is pressed, it tests whether the device is functioning properly in terms of its physical components and mechanisms. It helps ensure that the device is able to properly detect and interrupt electrical faults or imbalances, providing a safe electrical environment.

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  • 20. 

    Additional protection in a room containing a sauna would be

    • Barriers

    • Placing out of reach

    • IPX6 rated accessories

    • By the way of RCD

    Correct Answer
    A. By the way of RCD
    Explanation
    An RCD (Residual Current Device) is a safety device that quickly shuts off power to a circuit if it detects a leakage current. In the context of a room containing a sauna, using an RCD would provide additional protection by cutting off power in case of any electrical faults or accidents, reducing the risk of electric shock or fire. This safety measure ensures the well-being of individuals using the sauna and prevents potential hazards.

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  • 21. 

    Socket outlets supplying caravan pitches should be at a height of

    • 0.5m off the ground

    • 0.25m off the ground

    • 0.5m to 1.5m off the ground measured to the highest part of the socket outlet

    • 0.5m to 1.5m off the ground measured to the lowest part of the socket outlet

    Correct Answer
    A. 0.5m to 1.5m off the ground measured to the lowest part of the socket outlet
    Explanation
    The correct answer is 0.5m to 1.5m off the ground measured to the lowest part of the socket outlet. This is because the height of socket outlets supplying caravan pitches should be within this range to ensure easy access and safe use for the users. The measurement is taken to the lowest part of the socket outlet to ensure that even the lowest part is within the specified height range.

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  • 22. 

    For low voltage equipment, systems and installation, basic protection generally corresponds to protection against

    • Mechanical damage

    • Circuit overload

    • Direct contact

    • Risk of burns

    Correct Answer
    A. Direct contact
    Explanation
    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.

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  • 23. 

    Before conducting an insulation resistance test you should

    • Ensure that the polarity is correct

    • Ensure correct RCDs are fitted

    • Ensure that the earth fault loop impedance is satisfactory

    • Ensure that all lamps are removed

    Correct Answer
    A. Ensure that all lamps are removed
    Explanation
    Before conducting an insulation resistance test, it is important to ensure that all lamps are removed. This is because lamps can create a parallel path for current flow, which can lead to inaccurate test results. By removing all lamps, the insulation resistance test can accurately measure the resistance of the insulation in the circuit without any interference from the lamps.

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  • 24. 

    In areas that are subject to vehicle movement on a caravan site, overhead distribution cables shall be installed at a height of

    • 6m

    • 5m

    • 15m

    • 10m

    Correct Answer
    A. 6m
    Explanation
    In areas that are subject to vehicle movement on a caravan site, overhead distribution cables should be installed at a height of 6m. This height ensures that the cables are high enough to avoid any potential damage or interference from vehicles passing underneath. It also helps to ensure the safety of both the vehicles and the people on the site, as it reduces the risk of accidents or collisions with the cables. Installing the cables at a height of 6m provides a suitable clearance for vehicles and helps to maintain a safe and functional environment on the caravan site.

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  • 25. 

    When considering access of gangways, gangways longer than 10m shall be

    • Accessible from above and below

    • Accessible from either end

    • Accessible from both ends

    • Provided with a rechargeable torch at either end

    Correct Answer
    A. Accessible from both ends
    Explanation
    Gangways longer than 10m should be accessible from both ends. This means that people should be able to enter and exit the gangway from either end, ensuring easy and convenient access for all. Having access from both ends allows for better flow of people and reduces congestion. It also ensures that in case of an emergency, people can quickly evacuate from either end of the gangway.

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  • 26. 

    LPZ stands for

    • Limited protection zone

    • Luminaire protection zone

    • Lightning protection zone

    • Line protection zone

    Correct Answer
    A. Lightning protection zone
    Explanation
    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.

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  • 27. 

    In a swimming pool switchgear or control gear shall not be installed in

    • Zone 1 only

    • Zone 2 only

    • Zone 1 and zone 2

    • Zone 0

    Correct Answer
    A. Zone 0
    Explanation
    Zone 0 is the area inside the swimming pool where there is a high risk of water immersion. It is the most hazardous area in terms of electrical safety. Therefore, switchgear or control gear should never be installed in zone 0 to prevent electrical accidents and ensure the safety of swimmers and pool users.

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  • 28. 

    Extraneous-conductive-parts in, or on, the floor, e.g. concrete reinforcement in general or reinforcement of cellars for liquid manure in agricultural installations, shall be connected to

    • The supplementary equipotential bonding.

    • The neutral conductor

    • The protective conductor

    • The ground

    Correct Answer
    A. The supplementary equipotential bonding.
    Explanation
    Extraneous-conductive parts on the floor, such as concrete reinforcement or reinforcement of cellars for liquid manure in agricultural installations, should be connected to the supplementary equipotential bonding. This is because the supplementary equipotential bonding helps to maintain equal electrical potential between conductive parts, reducing the risk of electric shock or other electrical hazards. Connecting these extraneous-conductive parts to the supplementary equipotential bonding ensures that they are effectively grounded and eliminates the potential for electrical accidents.

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  • 29. 

    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:

    • 0.3 m

    • 0.4 m

    • 0.5 m

    • 0.7 m

    Correct Answer
    A. 0.5 m
    Explanation
    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.

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  • 30. 

    At the origin of an electrical installation, the prospective fault current must be taken into account when

    • Selecting the type of overcurrent device to be installed

    • Applying diversity to the installation

    • Assessing the earthing arrangement

    • Estimating the external fault loop impedance

    Correct Answer
    A. Selecting the type of overcurrent device to be installed
    Explanation
    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.

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  • 31. 

    When installing a socket outlet powered by a SELV circuit within a bathroom, the safety source shall be installed

    • As close as possible

    • Between zone 1 and 2

    • Between zone 0 and 2

    • Outside zones 0,1 and 2

    Correct Answer
    A. Outside zones 0,1 and 2
    Explanation
    The safety source for a socket outlet powered by a SELV circuit in a bathroom should be installed outside zones 0, 1, and 2. This is because zones 0, 1, and 2 are the areas in a bathroom where there is a higher risk of water contact, and therefore, electrical installations should be kept away from these zones to ensure safety. By installing the safety source outside these zones, the risk of electrical shock or damage due to water exposure is minimized.

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  • 32. 

    Which protective measure in installations used for exhibitions is not permitted?

    • Extra-low voltage by SELV or PELV

    • Electrical separation

    • Obstacles and placing out of reach

    • Double or reinforced isolation

    Correct Answer
    A. Obstacles and placing out of reach
    Explanation
    Obstacles and placing out of reach is not a permitted protective measure in installations used for exhibitions. This is because it does not provide a reliable and standardized method of protection against electrical hazards. Instead, installations should adhere to measures such as extra-low voltage by SELV or PELV, electrical separation, and double or reinforced isolation to ensure the safety of individuals and equipment.

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  • 33. 

    Which fault protection measure applies to an EV installation?

    • RCD protection on every charging point

    • Single RCD protection on multiple charging points

    • A combination of RCD and fuse protection

    • Protection by putting out of reach

    Correct Answer
    A. RCD protection on every charging point
    Explanation
    The correct answer is RCD protection on every charging point. This measure ensures that each charging point is equipped with a Residual Current Device (RCD), which is a safety device that quickly shuts off the electricity supply if it detects a fault or imbalance in the electrical circuit. This helps to protect both the charging point and the electric vehicle from potential electrical hazards, such as electric shock or fire. By having RCD protection on every charging point, the overall safety of the EV installation is significantly enhanced.

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  • 34. 

    When determining design current, the correction factor that is applied to a BS3036 rewirable fuse is

    • 0.752

    • 0.527

    • 0.725

    • 1.725

    Correct Answer
    A. 0.725
    Explanation
    The correction factor of 0.725 is applied to a BS3036 rewirable fuse when determining design current. This correction factor is used to account for the characteristics of the fuse and ensure that the correct current rating is chosen for the circuit. By applying this correction factor, the design current can be accurately determined, taking into consideration the specific properties of the BS3036 rewirable fuse.

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  • 35. 

    Which of the following is NOT considered as a harmful effect of heat or thermal radiation emitted by electrical equipment?

    • Combustion, ignition, or degradation of materials

    • Impairment of the safe function of installed equipment

    • Risk of bums

    • Radioactivity

    Correct Answer
    A. Radioactivity
    Explanation
    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.

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  • 36. 

    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

    • International Standard

    • Conventional Standard

    • Harmonized Standard

    • Common Standard

    Correct Answer
    A. Harmonized Standard
    Explanation
    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.

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  • 37. 

    An overcurrent protective device installed at the origin of a circuit must have a breaking capacity of

    • At least 15kA

    • Equivalent or more than the prospective short circuit current

    • Twice the prospective short circuit current

    • Equivalent to maximum earth fault current

    Correct Answer
    A. Equivalent or more than the prospective short circuit current
    Explanation
    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.

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  • 38. 

    Extraneous-conductive part is a part liable to introduce a potential, generally Earth potential, and

    • Being an earthing part of the electrical installation

    • Forming part of the electrical installation

    • Is intended to be an earthing part of the electrical installation

    • Not forming part of the electrical installation

    Correct Answer
    A. Not forming part of the electrical installation
    Explanation
    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.

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  • 39. 

    The third letter of the code for system earthing type has a meaning of

    • Relationship of the exposed-conductive-parts of the installation to Earth

    • Relationship of the exposed-conductive-parts of the installation to the power system

    • Relationship of the power system to Earth

    • Arrangement of neutral and protective conductors

    Correct Answer
    A. Arrangement of neutral and protective conductors
    Explanation
    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.

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  • 40. 

    If an RCD is used in a TN-C-S system, which conductor shall not be used on the load side?

    • PEN conductor

    • Protective conductor

    • Neutral conductor

    • Line conductor

    Correct Answer
    A. PEN conductor
    Explanation
    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.

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  • 41. 

    The maximum disconnection time for a 400v a.c. final circuit with a TN supply is

    • 5s

    • 0.2s

    • 0.5s

    • 5ms

    Correct Answer
    A. 0.2s
    Explanation
    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.

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  • 42. 

    Which system a step-up autotransformer shall not be connected to?

    • TT

    • IT

    • TN

    • TN and TT

    Correct Answer
    A. IT
    Explanation
    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.

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  • 43. 

    Which one is NOT an item for inspection checking?

    • Correct connection of accessories and equipment

    • Presence of fire barriers, suitable seals and protection against thermal effects

    • Methods of protection against voltage drop

    • Selection of equipment and protective measures appropriate to external influences

    Correct Answer
    A. Methods of protection against voltage drop
    Explanation
    The correct answer is "Methods of protection against voltage drop." This is not an item for inspection checking because voltage drop is a phenomenon that occurs in electrical systems due to the resistance of conductors. It is not something that can be visually inspected or checked during an inspection. The other options, such as correct connection of accessories and equipment, presence of fire barriers, and selection of equipment appropriate to external influences, are all valid items for inspection checking as they relate to the safety and functionality of the electrical system.

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  • 44. 

    The fundamental principles of BS7671 state that persons and livestock shall be protected against injury as a consequence of overvoltages originating from

    • Motors running

    • The operation of circuit breakers

    • Atmospheric events

    • Voltage recovery

    Correct Answer
    A. Atmospheric events
    Explanation
    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.

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  • 45. 

    BS7671 IET Wiring Regulations define extra low voltage ripple-free d.c. as not exceeding

    • 50 volts d.c.

    • 120 volts d.c.

    • 150 volts d.c.

    • 200 volts d.c.

    Correct Answer
    A. 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.

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  • 46. 

    For protection against burns the temperature limit under normal load conditions for a hand-held part with non-metallic surface is

    • 50 ¡C

    • 55 ¡C

    • 60 ¡C

    • 65 ¡C

    Correct Answer
    A. 65 ¡C
    Explanation
    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.

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  • 47. 

    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

    • 2.5 kV

    • 4 kV

    • 6 kV

    • 8 kV

    Correct Answer
    A. 6 kV
    Explanation
    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.

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  • 48. 

    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?

    • 80 mm

    • 100 mm

    • 120 mm

    • 150 mm

    Correct Answer
    A. 100 mm
    Explanation
    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.

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  • 49. 

    During the initial verification of an installation, which of the following forms part of the checklist?

    • Maximum demand and diversity

    • Design briefs

    • Contractors notes

    • Presence of diagrams and instructions

    Correct Answer
    A. Presence of diagrams and instructions
    Explanation
    During the initial verification of an installation, the presence of diagrams and instructions forms part of the checklist. This is because diagrams and instructions provide crucial information about the installation process and help ensure that the installation is carried out correctly. They serve as a reference for the contractors and help them understand the requirements and guidelines for the installation. By checking the presence of diagrams and instructions, the verification process can ensure that the necessary documentation is available and accessible for a successful installation.

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Quiz Review Timeline (Updated): Mar 15, 2023 +

Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Mar 15, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Jun 04, 2014
    Quiz Created by
    Julian
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