Hornbill Industrial Training Mock Compex Online Exam

1. For workers in potentially explosive environments it is essential to understand:

The basic requirements of working in hazardous areas

The manufacturers literature

The manufacturing standards

Panel wiring diagrams

Workers in potentially explosive environments need to understand the basic requirements of working in hazardous areas in order to ensure their safety. This includes knowledge of safety protocols, proper handling of equipment, and understanding the potential risks and hazards associated with their work environment. By having a thorough understanding of these basic requirements, workers can minimize the risk of accidents and ensure a safe working environment for themselves and their colleagues.

Explanation

Workers in potentially explosive environments need to understand the basic requirements of working in hazardous areas in order to ensure their safety. This includes knowledge of safety protocols, proper handling of equipment, and understanding the potential risks and hazards associated with their work environment. By having a thorough understanding of these basic requirements, workers can minimize the risk of accidents and ensure a safe working environment for themselves and their colleagues.

2. IEC divides equipment into Equipment Protection Levels EPLs. What are they?

Ga, Gb, Gc

Gd, Ge, Gn

Gia, Gib, Gic

Gx, Gy, Gz

IEC (International Electrotechnical Commission) divides equipment into Equipment Protection Levels (EPLs) for the purpose of classifying the level of protection provided against potential hazards. The correct answer options, Ga, Gb, and Gc, represent three different EPLs. These EPLs indicate the level of protection against potential explosions caused by flammable gases or vapors. Ga represents the highest level of protection, suitable for hazardous areas with the highest risk, while Gb and Gc represent lower levels of protection suitable for areas with lower risks.

Explanation

IEC (International Electrotechnical Commission) divides equipment into Equipment Protection Levels (EPLs) for the purpose of classifying the level of protection provided against potential hazards. The correct answer options, Ga, Gb, and Gc, represent three different EPLs. These EPLs indicate the level of protection against potential explosions caused by flammable gases or vapors. Ga represents the highest level of protection, suitable for hazardous areas with the highest risk, while Gb and Gc represent lower levels of protection suitable for areas with lower risks.

3. A power-on test is to be carried out on a flanged Ex d item of equipment after a detailed inspection. What is the minimum requirement of the enclosure:

Put at least one bolt back and hang a danger notice

Put at least half the bolts back and hang a danger notice

Put all bolts back spanner tight and check the flange gaps

Put no bolts back and leave it until the next inspection

After a detailed inspection, the minimum requirement for the enclosure is to put all bolts back spanner tight and check the flange gaps. This ensures that the equipment is properly secured and the flange gaps are checked for any potential leaks or hazards. Hanging a danger notice alone would not be sufficient to ensure the safety and functionality of the equipment.

Explanation

After a detailed inspection, the minimum requirement for the enclosure is to put all bolts back spanner tight and check the flange gaps. This ensures that the equipment is properly secured and the flange gaps are checked for any potential leaks or hazards. Hanging a danger notice alone would not be sufficient to ensure the safety and functionality of the equipment.

4. Which of the following is not required for combustion of a flammable material

Oxygen

An Enclosure

Ignition source

Fuel

An enclosure is not required for the combustion of a flammable material. Combustion can occur in an open environment where there is sufficient oxygen, an ignition source, and fuel. An enclosure, such as a closed container or confined space, can enhance the combustion process by containing the heat and allowing it to build up, leading to more intense and potentially dangerous fires. However, it is not necessary for the actual combustion to take place.

Explanation

An enclosure is not required for the combustion of a flammable material. Combustion can occur in an open environment where there is sufficient oxygen, an ignition source, and fuel. An enclosure, such as a closed container or confined space, can enhance the combustion process by containing the heat and allowing it to build up, leading to more intense and potentially dangerous fires. However, it is not necessary for the actual combustion to take place.

5. Which of the following is not needed for combustion to occur:

Ignition source

Fuel supply

Enclosure

Oxygen

Combustion is a chemical reaction that requires three main components: fuel, oxygen, and an ignition source. The fuel is the material that undergoes combustion, while oxygen is necessary for the reaction to occur. The ignition source provides the initial heat energy needed to start the reaction. However, an enclosure is not needed for combustion to occur. An enclosure refers to a confined space or container, which is not essential for the combustion process. Combustion can take place in an open environment without any enclosure.

Explanation

Combustion is a chemical reaction that requires three main components: fuel, oxygen, and an ignition source. The fuel is the material that undergoes combustion, while oxygen is necessary for the reaction to occur. The ignition source provides the initial heat energy needed to start the reaction. However, an enclosure is not needed for combustion to occur. An enclosure refers to a confined space or container, which is not essential for the combustion process. Combustion can take place in an open environment without any enclosure.

6. Equipment marked IECExBAS06.0014X. What does the X indicate:

The equipment must be installed in a safe area

The equipment cannot be used outdoors

The equipment does not have an IP rating

Special conditions apply, refer to documentation

The "X" in the equipment marking IECExBAS06.0014X indicates that special conditions apply to the equipment and these conditions can be found in the documentation. This means that there may be specific requirements or limitations for the use or installation of the equipment that need to be followed, and these details can be found in the accompanying documentation provided by the manufacturer or supplier.

Explanation

The "X" in the equipment marking IECExBAS06.0014X indicates that special conditions apply to the equipment and these conditions can be found in the documentation. This means that there may be specific requirements or limitations for the use or installation of the equipment that need to be followed, and these details can be found in the accompanying documentation provided by the manufacturer or supplier.

7. Cable glands entering a flameproof enclosure are required to meet what minimum thread engagements

5 full threads

8 full threads

3 full threads

10 full threads

Cable glands entering a flameproof enclosure are required to meet a minimum of 5 full threads. This means that the cable glands must have at least 5 complete turns or rotations when inserted into the enclosure to ensure a secure and tight fit. This is important in flameproof enclosures as it helps to prevent the entry of any flammable gases or substances, reducing the risk of explosions or fires. Having a sufficient number of thread engagements ensures a reliable and safe connection between the cable gland and the enclosure.

Explanation

Cable glands entering a flameproof enclosure are required to meet a minimum of 5 full threads. This means that the cable glands must have at least 5 complete turns or rotations when inserted into the enclosure to ensure a secure and tight fit. This is important in flameproof enclosures as it helps to prevent the entry of any flammable gases or substances, reducing the risk of explosions or fires. Having a sufficient number of thread engagements ensures a reliable and safe connection between the cable gland and the enclosure.

8. Before working in a hazardous area which one of the following is necessary to understand

Manufacturers documentation

The basic requirements for working in zoned areas

Circuit Diagrams

How the equipment operates

To work in a hazardous area, it is necessary to understand the basic requirements for working in zoned areas. This includes knowledge of the safety protocols, regulations, and precautions that need to be followed while working in such areas. Understanding these requirements is crucial to ensure the safety of oneself and others in the hazardous environment. It helps in preventing accidents, minimizing risks, and effectively managing any potential dangers that may arise in zoned areas.

Explanation

To work in a hazardous area, it is necessary to understand the basic requirements for working in zoned areas. This includes knowledge of the safety protocols, regulations, and precautions that need to be followed while working in such areas. Understanding these requirements is crucial to ensure the safety of oneself and others in the hazardous environment. It helps in preventing accidents, minimizing risks, and effectively managing any potential dangers that may arise in zoned areas.

9. What are the requirements of threaded entry into an Ex d enclosure:

Three fully engaged threads

Five fully engaged threads

Eight fully engaged threads

Ten fully engaged threads

Threaded entry into an Ex d enclosure requires five fully engaged threads. This means that the threads on the entry point must be completely threaded into the enclosure to ensure a secure and tight fit. Having five fully engaged threads ensures that the connection is strong and reduces the risk of any leaks or hazardous substances escaping from the enclosure.

Explanation

Threaded entry into an Ex d enclosure requires five fully engaged threads. This means that the threads on the entry point must be completely threaded into the enclosure to ensure a secure and tight fit. Having five fully engaged threads ensures that the connection is strong and reduces the risk of any leaks or hazardous substances escaping from the enclosure.

10. Which one of the following statements represents the presence flammable mixture in Zone 0

Not likely to be present in normal operations

Not present during normal operations

Present continuously, or for long periods

Present in normal operations occasionally

The correct answer is "present continuously, or for long periods." This statement accurately describes the presence of a flammable mixture in Zone 0. Zone 0 refers to an area where explosive gas is likely to be present continuously or for long periods of time, such as inside a tank or a vessel. The other options suggest that the flammable mixture is not likely to be present or only present occasionally, which does not align with the characteristics of Zone 0.

Explanation

The correct answer is "present continuously, or for long periods." This statement accurately describes the presence of a flammable mixture in Zone 0. Zone 0 refers to an area where explosive gas is likely to be present continuously or for long periods of time, such as inside a tank or a vessel. The other options suggest that the flammable mixture is not likely to be present or only present occasionally, which does not align with the characteristics of Zone 0.

11. How should finely stranded conductors be terminated:

Twisting the strands

Soldering the strands

Fit coloured sleeving

Fit cable lugs or core-end sleeves

Finely stranded conductors should be terminated by fitting cable lugs or core-end sleeves. This is because the fine strands of the conductor can easily become damaged or frayed if left exposed, leading to poor electrical connections or potential safety hazards. By fitting cable lugs or core-end sleeves, the strands are protected and secured, ensuring a reliable and safe termination.

Explanation

Finely stranded conductors should be terminated by fitting cable lugs or core-end sleeves. This is because the fine strands of the conductor can easily become damaged or frayed if left exposed, leading to poor electrical connections or potential safety hazards. By fitting cable lugs or core-end sleeves, the strands are protected and secured, ensuring a reliable and safe termination.

12. IEC 60079-14 requires levels of attainment for workers, What is required for technicians:

Only evidence of having the necessary skills for the scope of work

Only evidence of having the necessary skills for the scope of work and competence across a range of activities

Have HNC in Engineering

The correct answer is evidence of having the necessary skills for the scope of work and competence across a range of activities and of relevant knowledge and understanding of protection types. This requirement ensures that technicians have not only the necessary skills for their specific job, but also the ability to perform a variety of tasks and have knowledge of different protection types. This ensures that they are well-rounded and capable of handling different situations and tasks within their field. Having this level of competence and knowledge is essential for technicians to effectively carry out their responsibilities.

Explanation

The correct answer is evidence of having the necessary skills for the scope of work and competence across a range of activities and of relevant knowledge and understanding of protection types. This requirement ensures that technicians have not only the necessary skills for their specific job, but also the ability to perform a variety of tasks and have knowledge of different protection types. This ensures that they are well-rounded and capable of handling different situations and tasks within their field. Having this level of competence and knowledge is essential for technicians to effectively carry out their responsibilities.

13. The Atex 95 Directive is concerned with:

The health and safety of workers

The electricity at work act

The design and trade of explosion protection equipment

Standardisation of electrical voltages

The Atex 95 Directive is concerned with the design and trade of explosion protection equipment. This means that it focuses on regulating and ensuring the safety of equipment that is specifically designed to prevent and protect against explosions. The directive aims to establish standards and guidelines for the design, manufacturing, and trade of such equipment to ensure its effectiveness and compliance with safety regulations. This is important to prevent accidents and protect workers from potential hazards in explosive environments.

Explanation

The Atex 95 Directive is concerned with the design and trade of explosion protection equipment. This means that it focuses on regulating and ensuring the safety of equipment that is specifically designed to prevent and protect against explosions. The directive aims to establish standards and guidelines for the design, manufacturing, and trade of such equipment to ensure its effectiveness and compliance with safety regulations. This is important to prevent accidents and protect workers from potential hazards in explosive environments.

14. Pressure piling can result when:

Heavy equipment is mounted on piles

An ignition in one part of an enclosure causes higher explosion pressure in another part

There is a build up of pressure causing material fatigue

The gas pressure causes a vent to open

When an ignition occurs in one part of an enclosure, it can cause a chain reaction leading to higher explosion pressure in another part. This is because the initial ignition releases energy and heat, which can ignite other flammable substances or gases in the enclosure. As the combustion process continues, the pressure within the enclosure increases, potentially causing an explosion. This phenomenon is known as pressure piling and can be dangerous if proper safety measures are not in place.

Explanation

When an ignition occurs in one part of an enclosure, it can cause a chain reaction leading to higher explosion pressure in another part. This is because the initial ignition releases energy and heat, which can ignite other flammable substances or gases in the enclosure. As the combustion process continues, the pressure within the enclosure increases, potentially causing an explosion. This phenomenon is known as pressure piling and can be dangerous if proper safety measures are not in place.

15. The requirement for glands entering Ex n equipment after 2007 are

Certified meeting the requirements on IEC60079-0

EX d Barrier Gland

Ex e Gland

Ex d Gland

The correct answer is "Certified meeting the requirements on IEC60079-0." This means that the glands entering Ex n equipment after 2007 must be certified and meet the requirements stated in the IEC60079-0 standard. This standard specifies the general requirements for equipment used in explosive atmospheres, ensuring that the equipment is safe to use in such environments. Therefore, it is essential for the glands to be certified and compliant with this standard to ensure the safety and functionality of the Ex n equipment.

Explanation

The correct answer is "Certified meeting the requirements on IEC60079-0." This means that the glands entering Ex n equipment after 2007 must be certified and meet the requirements stated in the IEC60079-0 standard. This standard specifies the general requirements for equipment used in explosive atmospheres, ensuring that the equipment is safe to use in such environments. Therefore, it is essential for the glands to be certified and compliant with this standard to ensure the safety and functionality of the Ex n equipment.

16. What is the design ambient temperature if not marked on the equipment:

-10oC to +20oC

-20oC to +40oC

-30oC to +60oC

-40oC to +80oC

The design ambient temperature refers to the range of temperatures within which the equipment is designed to operate effectively and safely. In this case, if the design ambient temperature is not marked on the equipment, it can be assumed to be -20oC to +40oC. This range allows for a moderate level of temperature variation, providing a suitable operating environment for the equipment.

Explanation

The design ambient temperature refers to the range of temperatures within which the equipment is designed to operate effectively and safely. In this case, if the design ambient temperature is not marked on the equipment, it can be assumed to be -20oC to +40oC. This range allows for a moderate level of temperature variation, providing a suitable operating environment for the equipment.

17. An item of equipment marked II without an A, B or C can be used:

The equipment is unsuitable for any area

The equipment can only be used in IIA areas

The equipment can be used in all gas group areas

The equipment can only be used in IIB area

The correct answer is that the equipment can be used in all gas group areas. This means that the equipment is suitable for use in any area, regardless of the gas group classification. The absence of A, B, or C markings indicates that the equipment is not limited to specific gas group areas and can be used safely in all of them.

Explanation

The correct answer is that the equipment can be used in all gas group areas. This means that the equipment is suitable for use in any area, regardless of the gas group classification. The absence of A, B, or C markings indicates that the equipment is not limited to specific gas group areas and can be used safely in all of them.

18. During a Hornbill Industrial Training mock session focusing on machine maintenance and safety, what is the recommended action when a critical pressure gauge on a hydraulic press registers within 5% above the normal operating range?

Continue operating the machine as long as the gauge does not exceed 10% of the normal range.

Stop the machine immediately and perform a standard safety check according to the operations manual.

Adjust the pressure release valve to immediately lower the pressure to the normal operating range.

Record the pressure reading and report it to the maintenance department at the end of the shift.

In an industrial training scenario, particularly one focused on machine maintenance and safety like Hornbill Industrial Training, the safety of operations is paramount. When a critical pressure gauge indicates a measurement above the normal operating range, even if it's only by 5%, it could potentially signal an underlying issue that may lead to equipment failure or safety hazards. The recommended action, therefore, would be to stop the machine immediately to prevent any risk of damage or injury and to conduct a safety check as per the protocols outlined in the operations manual. This reflects the best practice in industrial settings, which is to err on the side of caution when any potential safety issue arises.

Explanation

In an industrial training scenario, particularly one focused on machine maintenance and safety like Hornbill Industrial Training, the safety of operations is paramount. When a critical pressure gauge indicates a measurement above the normal operating range, even if it's only by 5%, it could potentially signal an underlying issue that may lead to equipment failure or safety hazards. The recommended action, therefore, would be to stop the machine immediately to prevent any risk of damage or injury and to conduct a safety check as per the protocols outlined in the operations manual. This reflects the best practice in industrial settings, which is to err on the side of caution when any potential safety issue arises.

19. What is the minimum IP rating of Ex n equipment

IP 20

IP 44

IP 54

IP 65

Ex n equipment refers to equipment that is designed for use in potentially explosive atmospheres. The IP rating, also known as the Ingress Protection rating, indicates the level of protection provided by the equipment against solid objects and liquids. In this case, the minimum IP rating required for Ex n equipment is IP 54. This means that the equipment is protected against dust and limited ingress of water, making it suitable for use in hazardous environments.

Explanation

Ex n equipment refers to equipment that is designed for use in potentially explosive atmospheres. The IP rating, also known as the Ingress Protection rating, indicates the level of protection provided by the equipment against solid objects and liquids. In this case, the minimum IP rating required for Ex n equipment is IP 54. This means that the equipment is protected against dust and limited ingress of water, making it suitable for use in hazardous environments.

20. Cable glands installed into Ex n boxes after 2007 are required to be:

Certified Ex d gland

Certified Ex e gland

Certified Barrier gland

Certified to IEC 60079

After 2007, cable glands installed into Ex n boxes are required to be certified to IEC 60079. This certification ensures that the cable glands meet the international standards for electrical equipment used in explosive atmospheres. The IEC 60079 standard specifies the requirements for the design, construction, testing, and marking of electrical equipment to ensure safety in hazardous areas. By being certified to this standard, the cable glands are deemed suitable for use in potentially explosive environments, providing assurance of their safety and reliability.

Explanation

After 2007, cable glands installed into Ex n boxes are required to be certified to IEC 60079. This certification ensures that the cable glands meet the international standards for electrical equipment used in explosive atmospheres. The IEC 60079 standard specifies the requirements for the design, construction, testing, and marking of electrical equipment to ensure safety in hazardous areas. By being certified to this standard, the cable glands are deemed suitable for use in potentially explosive environments, providing assurance of their safety and reliability.

21. Ex e equipment signifies:

Flameproof

Increased safety

Purged

Intrinsically safe

Ex e equipment signifies increased safety. This means that the equipment is designed and constructed in a way that reduces the risk of ignition and the potential for the creation of sparks or excessive temperatures. Increased safety equipment is suitable for use in hazardous environments where there may be flammable gases, vapors, or dust present. It provides a higher level of protection compared to other types of equipment, such as flameproof or purged, ensuring a safer working environment.

Explanation

Ex e equipment signifies increased safety. This means that the equipment is designed and constructed in a way that reduces the risk of ignition and the potential for the creation of sparks or excessive temperatures. Increased safety equipment is suitable for use in hazardous environments where there may be flammable gases, vapors, or dust present. It provides a higher level of protection compared to other types of equipment, such as flameproof or purged, ensuring a safer working environment.

22. Which of the following is a GRADE of inspection:

Close

Periodic

Frequent

Sample

A close inspection refers to a detailed examination of something, typically done with great attention to detail and thoroughness. It involves closely examining every aspect or component of the item being inspected. Close inspections are often conducted to ensure that there are no defects, errors, or issues that may have been missed during previous inspections. This type of inspection is usually done when a high level of accuracy and precision is required.

Explanation

A close inspection refers to a detailed examination of something, typically done with great attention to detail and thoroughness. It involves closely examining every aspect or component of the item being inspected. Close inspections are often conducted to ensure that there are no defects, errors, or issues that may have been missed during previous inspections. This type of inspection is usually done when a high level of accuracy and precision is required.

23. The fixings of Ex d equipment should:

All be spanner tight

Be tightened using a torque wrench set at 50Nm

Have only alternate bolts tightened

Be missing

The fixings of Ex d equipment should all be spanner tight. This means that all the fixings should be tightened securely using a spanner tool. This ensures that the equipment is properly sealed and prevents any potential leakage or release of hazardous substances. Tightening all the fixings also helps to maintain the integrity of the equipment and prevent any accidental dislodgement or damage.

Explanation

The fixings of Ex d equipment should all be spanner tight. This means that all the fixings should be tightened securely using a spanner tool. This ensures that the equipment is properly sealed and prevents any potential leakage or release of hazardous substances. Tightening all the fixings also helps to maintain the integrity of the equipment and prevent any accidental dislodgement or damage.

24. Ex d equipment is called flameproof because:

It contains flammable materials

If the equipment is on fire it will continue to function

It will contain an internal explosion

It's too heavy to be used

Ex d equipment is called flameproof because it is designed to contain an internal explosion. This means that if an explosion occurs within the equipment, it will not propagate to the surrounding environment. The equipment is constructed in such a way that it can withstand and contain the pressure and flames generated by an internal explosion, preventing it from causing further damage or igniting any flammable materials in the vicinity. This makes it a safer option for use in hazardous environments where there is a risk of explosions.

Explanation

Ex d equipment is called flameproof because it is designed to contain an internal explosion. This means that if an explosion occurs within the equipment, it will not propagate to the surrounding environment. The equipment is constructed in such a way that it can withstand and contain the pressure and flames generated by an internal explosion, preventing it from causing further damage or igniting any flammable materials in the vicinity. This makes it a safer option for use in hazardous environments where there is a risk of explosions.

25. ATEX divides equipment into groups and categories. What are they?

Group I - categories 1,2,3

Group II - Categories 1,2,3

Group III - Categories 1,2,3

Group IIII - Categories 1,2,3

ATEX divides equipment into groups and categories for the purpose of classifying them based on their potential for causing an explosion in hazardous environments. The correct answer states that Group II is divided into Categories 1, 2, and 3. This means that equipment in Group II is intended for use in areas where explosive atmospheres caused by gases, vapors, or mists are likely to occur occasionally or for short periods. Category 1 represents the highest level of protection, suitable for areas with a high risk of explosion, while Category 3 represents the lowest level of protection, suitable for areas with a lower risk of explosion.

Explanation

ATEX divides equipment into groups and categories for the purpose of classifying them based on their potential for causing an explosion in hazardous environments. The correct answer states that Group II is divided into Categories 1, 2, and 3. This means that equipment in Group II is intended for use in areas where explosive atmospheres caused by gases, vapors, or mists are likely to occur occasionally or for short periods. Category 1 represents the highest level of protection, suitable for areas with a high risk of explosion, while Category 3 represents the lowest level of protection, suitable for areas with a lower risk of explosion.

26. On an area classification drawing what would represent Zone 1:

Circles

Cross hatching

As symbols shown on the drawing

Slanted lines

Zone 1 on an area classification drawing would be represented by symbols shown on the drawing. This means that specific symbols or icons would be used to indicate the presence of Zone 1 hazardous areas. These symbols could vary depending on the industry or specific regulations being followed. Using symbols helps to clearly identify and communicate the location of Zone 1 areas, which are defined as areas where flammable gases, vapors, or liquids are likely to be present in normal operating conditions.

Explanation

Zone 1 on an area classification drawing would be represented by symbols shown on the drawing. This means that specific symbols or icons would be used to indicate the presence of Zone 1 hazardous areas. These symbols could vary depending on the industry or specific regulations being followed. Using symbols helps to clearly identify and communicate the location of Zone 1 areas, which are defined as areas where flammable gases, vapors, or liquids are likely to be present in normal operating conditions.

27. Ex e equipment installed in 2005, which gland is not acceptable

Uncertified plastic

Uncertified E1W

E1W ex e

E1W Ex d

The correct answer is "Uncertified plastic" because when it comes to Ex e equipment, the use of uncertified plastic materials is not acceptable. Ex e refers to a type of electrical equipment that is designed to prevent the occurrence of arcs, sparks, or hot surfaces that could ignite explosive atmospheres. In order to ensure the safety and reliability of Ex e equipment, it is crucial to use certified materials that meet the necessary standards and regulations. Uncertified plastic materials may not have undergone the required testing and certification processes, therefore making them unsuitable for use in Ex e equipment.

Explanation

The correct answer is "Uncertified plastic" because when it comes to Ex e equipment, the use of uncertified plastic materials is not acceptable. Ex e refers to a type of electrical equipment that is designed to prevent the occurrence of arcs, sparks, or hot surfaces that could ignite explosive atmospheres. In order to ensure the safety and reliability of Ex e equipment, it is crucial to use certified materials that meet the necessary standards and regulations. Uncertified plastic materials may not have undergone the required testing and certification processes, therefore making them unsuitable for use in Ex e equipment.

28. The purpose of Barriers is to:

Limit the maximum energy flow to apparatus

Allow any apparatus to be installed

Allow apparatus only marked Ex i to be installed

Limit the maximum temperature of the apparatus

Barriers are used to limit the maximum energy flow to apparatus. This means that they control and restrict the amount of energy that can be transmitted to the apparatus, ensuring that it does not exceed a certain level. By doing so, barriers help to prevent damage or malfunction of the apparatus, ensuring its safe operation. This is an important safety measure in hazardous environments where excessive energy flow can pose a risk.

Explanation

Barriers are used to limit the maximum energy flow to apparatus. This means that they control and restrict the amount of energy that can be transmitted to the apparatus, ensuring that it does not exceed a certain level. By doing so, barriers help to prevent damage or malfunction of the apparatus, ensuring its safe operation. This is an important safety measure in hazardous environments where excessive energy flow can pose a risk.

29. The minimum gap between Ex d flanged joints and other obstructions in a IIC environment is:

10mm

20mm

30mm

40mm

In an IIC environment, the minimum gap between Ex d flanged joints and other obstructions is 40mm. This is necessary to ensure proper ventilation and prevent the buildup of explosive gases. A larger gap allows for better dissipation of heat and reduces the risk of ignition or explosion. It also provides enough space for maintenance and inspection activities to be carried out safely. Therefore, a 40mm minimum gap is required to meet the safety standards in an IIC environment.

Explanation

In an IIC environment, the minimum gap between Ex d flanged joints and other obstructions is 40mm. This is necessary to ensure proper ventilation and prevent the buildup of explosive gases. A larger gap allows for better dissipation of heat and reduces the risk of ignition or explosion. It also provides enough space for maintenance and inspection activities to be carried out safely. Therefore, a 40mm minimum gap is required to meet the safety standards in an IIC environment.

30. The numbers after letters IP represent

Solid particles and liquids

Solid particles and mechanical protection

Dust particles and condensation

Supply voltage and water pressure

The numbers after letters IP represent the level of protection provided by the enclosure against solid particles and liquids. The IP code is an international standard that classifies the degree of protection provided by electrical enclosures. The first digit indicates the level of protection against solid particles, such as dust, while the second digit indicates the level of protection against liquids, such as water. Therefore, the correct answer is "Solid particles and liquids."

Explanation

The numbers after letters IP represent the level of protection provided by the enclosure against solid particles and liquids. The IP code is an international standard that classifies the degree of protection provided by electrical enclosures. The first digit indicates the level of protection against solid particles, such as dust, while the second digit indicates the level of protection against liquids, such as water. Therefore, the correct answer is "Solid particles and liquids."

31. Equipment marked Ex e II T6 can be used in?

All gas groups

IIC only

IIA only

In combustible dusts only

The equipment marked Ex e II T6 can be used in all gas groups. This means that it is suitable for use in environments where there is a risk of explosive gases present, regardless of the specific gas group classification. The T6 designation indicates that the equipment can operate safely in environments with a maximum surface temperature of 85°C. Therefore, this equipment is versatile and can be used in a wide range of hazardous areas where explosive gases may be present.

Explanation

The equipment marked Ex e II T6 can be used in all gas groups. This means that it is suitable for use in environments where there is a risk of explosive gases present, regardless of the specific gas group classification. The T6 designation indicates that the equipment can operate safely in environments with a maximum surface temperature of 85°C. Therefore, this equipment is versatile and can be used in a wide range of hazardous areas where explosive gases may be present.

32. Equipment supplied with a greater than normal ambient temperature, which markings is relevant?

Ex d II T3 T65

Ex d II 60C T3

Ex e ii T3 40degC amb

Ex e II T3 -20C<Ta<+60C

The correct answer is "Ex e II T3 -20C

Explanation

The correct answer is "Ex e II T3 -20C

33. Live working under permit without a gas free certificate may be allowed if:

You are wearing PPE

You are working on IS circuits

The supply is SELV

The equipment Ex e

Working on IS (Intrinsically Safe) circuits means working on circuits that are designed to prevent the ignition of hazardous materials. These circuits are specifically designed to be safe in hazardous environments, so the need for a gas free certificate may not be necessary in this case.

Explanation

Working on IS (Intrinsically Safe) circuits means working on circuits that are designed to prevent the ignition of hazardous materials. These circuits are specifically designed to be safe in hazardous environments, so the need for a gas free certificate may not be necessary in this case.

34. Which is the ATEX installation standard?

IEC 60079-0

IEC 60079-10

IEC 60079-14

IEC 60079-17

The correct answer is IEC 60079-14. This standard specifically addresses the design, selection, installation, inspection, and maintenance of electrical installations in explosive atmospheres. It provides guidance on the requirements for the safe installation of electrical equipment and systems in hazardous areas, ensuring that they do not become a source of ignition. This standard is important for industries dealing with flammable substances, such as oil and gas, chemical, and pharmaceutical industries, to prevent accidents and ensure the safety of personnel and equipment.

Explanation

The correct answer is IEC 60079-14. This standard specifically addresses the design, selection, installation, inspection, and maintenance of electrical installations in explosive atmospheres. It provides guidance on the requirements for the safe installation of electrical equipment and systems in hazardous areas, ensuring that they do not become a source of ignition. This standard is important for industries dealing with flammable substances, such as oil and gas, chemical, and pharmaceutical industries, to prevent accidents and ensure the safety of personnel and equipment.

35. Aluminium cables are used in hazardous areas, what is the minimum CSA?

Less than 6mm

Less than10mm

Greater than 16mm

Greater than 25mm

Option 5

Aluminium cables are used in hazardous areas because they have better resistance to corrosion and are lighter than other materials. The minimum CSA (cross-sectional area) required for these cables is greater than 16mm. This is because a larger CSA ensures that the cables can handle higher current loads and reduces the risk of overheating, which is crucial in hazardous areas where safety is a priority.

Explanation

Aluminium cables are used in hazardous areas because they have better resistance to corrosion and are lighter than other materials. The minimum CSA (cross-sectional area) required for these cables is greater than 16mm. This is because a larger CSA ensures that the cables can handle higher current loads and reduces the risk of overheating, which is crucial in hazardous areas where safety is a priority.

36. What letters are used by the IEC for Equipment protection levels:

A,b,c

B,d,c

W,x,y

C,B,E

The IEC (International Electrotechnical Commission) uses the letters a, b, and c for Equipment protection levels. These letters are used to classify the degree of protection provided by electrical equipment against various environmental conditions, such as dust, water, and mechanical impacts. Each letter represents a different level of protection, with "a" indicating the highest level of protection and "c" indicating the lowest level.

Explanation

The IEC (International Electrotechnical Commission) uses the letters a, b, and c for Equipment protection levels. These letters are used to classify the degree of protection provided by electrical equipment against various environmental conditions, such as dust, water, and mechanical impacts. Each letter represents a different level of protection, with "a" indicating the highest level of protection and "c" indicating the lowest level.

37. What apparatus can be connected to a Zenner barrier:

Any apparatus

Simple apparatus marked Ex i

Only that specified in documentation

Only uncertified apparatus

The correct answer is "Only that specified in documentation." This means that the Zenner barrier can only be connected to the specific apparatus that is mentioned and approved in the documentation. It cannot be connected to any other apparatus or uncertified devices. This ensures that the Zenner barrier functions properly and safely with the designated equipment.

Explanation

The correct answer is "Only that specified in documentation." This means that the Zenner barrier can only be connected to the specific apparatus that is mentioned and approved in the documentation. It cannot be connected to any other apparatus or uncertified devices. This ensures that the Zenner barrier functions properly and safely with the designated equipment.

38. Equipment for use in Hydrogen area where EPL is Gc Cat 3, the equipment will be marked with

Ex e IIB T4

Ex n II T4

Ex d IIB T4

Ex e IIA T5

The correct answer, "Ex n II T4," indicates that the equipment is suitable for use in a hydrogen area with a gas group of II and a maximum surface temperature of T4. The "Ex n" marking signifies that the equipment is designed for non-sparking operations and is suitable for use in a potentially explosive atmosphere. The "II" classification indicates that the equipment is suitable for use in areas with a high risk of explosion. The "T4" rating indicates that the equipment can operate safely at a maximum surface temperature of 135°C.

Explanation

The correct answer, "Ex n II T4," indicates that the equipment is suitable for use in a hydrogen area with a gas group of II and a maximum surface temperature of T4. The "Ex n" marking signifies that the equipment is designed for non-sparking operations and is suitable for use in a potentially explosive atmosphere. The "II" classification indicates that the equipment is suitable for use in areas with a high risk of explosion. The "T4" rating indicates that the equipment can operate safely at a maximum surface temperature of 135°C.

39. What grade of inspection would the dismantling of a gland take:

Visual

Close

Detailed

Periodic

The dismantling of a gland would require a detailed inspection. This is because dismantling involves taking apart the gland and examining each component closely to ensure that it is in proper working condition. A detailed inspection would involve thoroughly examining each part of the gland, checking for any signs of damage or wear, and ensuring that all components are functioning correctly. This level of inspection is necessary to ensure the gland is in optimal condition and to identify any potential issues that may need to be addressed.

Explanation

The dismantling of a gland would require a detailed inspection. This is because dismantling involves taking apart the gland and examining each component closely to ensure that it is in proper working condition. A detailed inspection would involve thoroughly examining each part of the gland, checking for any signs of damage or wear, and ensuring that all components are functioning correctly. This level of inspection is necessary to ensure the gland is in optimal condition and to identify any potential issues that may need to be addressed.

40. Components such as an Switch or terminal suitable for installation within certified equipment has what additional letter added to the certification number, what letter is used?

X

U

A

C

Certified equipment components, such as a Switch or terminal, have an additional letter "U" added to the certification number. This indicates that the component is suitable for installation within certified equipment.

Explanation

Certified equipment components, such as a Switch or terminal, have an additional letter "U" added to the certification number. This indicates that the component is suitable for installation within certified equipment.

41. What does the T rating of equipment represent?

The equipment will reach this temperature in normal operation

The equipment will reach it's flash point in normal operation

The relevant surfaces of the equipment will not reach this temperature in normal operation

The equipment will exceed the temperature rating in normal operation

The T rating of equipment represents that the relevant surfaces of the equipment will not reach this temperature in normal operation. This means that the equipment is designed to operate within a certain temperature range, and the T rating ensures that the equipment will not exceed this specified temperature during normal use. It indicates that the equipment is safe to use without the risk of overheating or causing damage due to high temperatures.

Explanation

The T rating of equipment represents that the relevant surfaces of the equipment will not reach this temperature in normal operation. This means that the equipment is designed to operate within a certain temperature range, and the T rating ensures that the equipment will not exceed this specified temperature during normal use. It indicates that the equipment is safe to use without the risk of overheating or causing damage due to high temperatures.

42. Newly installed Ex d equipment may be installed in which of the following

Areas needing EPL Gc ( Cat 3G) equipment

Areas needing EPL Gb and Gc (2G & 3G) equipment

Areas needing EPL Ga (Cat 1G) equipment

Only areas needing EPL Gb (Cat 2G) equipment

Newly installed Ex d equipment may be installed in areas needing EPL Gb and Gc (2G & 3G) equipment because Ex d equipment is designed for use in hazardous areas where explosive gases and dust may be present. EPL Gb and Gc equipment are specifically designed for use in hazardous areas with different levels of gas and dust explosion risks. Therefore, newly installed Ex d equipment can be installed in areas that require both EPL Gb and Gc equipment to ensure safe operation in these hazardous environments.

Explanation

Newly installed Ex d equipment may be installed in areas needing EPL Gb and Gc (2G & 3G) equipment because Ex d equipment is designed for use in hazardous areas where explosive gases and dust may be present. EPL Gb and Gc equipment are specifically designed for use in hazardous areas with different levels of gas and dust explosion risks. Therefore, newly installed Ex d equipment can be installed in areas that require both EPL Gb and Gc equipment to ensure safe operation in these hazardous environments.

43. Cat 2 equipment may be installed in

Zone 2 & 21

Zone 20, 21 & 22

Zone 1 & 21 and less arduous areas

Zone 0 & 20

Cat 2 equipment may be installed in Zone 1 & 21 and less arduous areas because it is designed to be used in areas where there is a risk of the presence of flammable gases or vapors (Zone 1) and/or combustible dust (Zone 21). Additionally, it can also be used in less hazardous areas where the risk is lower (less arduous areas).

Explanation

Cat 2 equipment may be installed in Zone 1 & 21 and less arduous areas because it is designed to be used in areas where there is a risk of the presence of flammable gases or vapors (Zone 1) and/or combustible dust (Zone 21). Additionally, it can also be used in less hazardous areas where the risk is lower (less arduous areas).

44. Non IS and IS equipment is installed in the same enclosure. What is the minimum gap between terminals of each type:

3mm

6mm

30mm

50mm

The minimum gap between terminals of each type is 50mm. This is necessary to ensure proper insulation and prevent any potential interference or short-circuiting between the non IS and IS equipment. A larger gap allows for better separation and reduces the risk of any electrical hazards.

Explanation

The minimum gap between terminals of each type is 50mm. This is necessary to ensure proper insulation and prevent any potential interference or short-circuiting between the non IS and IS equipment. A larger gap allows for better separation and reduces the risk of any electrical hazards.

45. Which protection types can be used in an area requiring EPL Ga and category 1G

Ex d

Ex e

Ex ia

Ex ib

Ex ia is the correct answer because it is a protection type suitable for an area requiring EPL Ga and category 1G. Ex ia stands for "intrinsic safety" and it is a method of protection where the electrical energy in the circuit is limited to prevent ignition of hazardous substances. This protection type is commonly used in areas where explosive gases are present and it ensures that any electrical equipment used in the area will not produce sparks or excessive heat that could ignite the surrounding atmosphere.

Explanation

Ex ia is the correct answer because it is a protection type suitable for an area requiring EPL Ga and category 1G. Ex ia stands for "intrinsic safety" and it is a method of protection where the electrical energy in the circuit is limited to prevent ignition of hazardous substances. This protection type is commonly used in areas where explosive gases are present and it ensures that any electrical equipment used in the area will not produce sparks or excessive heat that could ignite the surrounding atmosphere.

46. Which gas group includes Hydrogen:

I

IIA

IIB

IIC

Gas groups are used in hazardous area classification, particularly in relation to electrical equipment used in environments where explosive atmospheres may be present. Group IIC is the gas group that includes gases with the highest level of hazard due to their low ignition energy, and hydrogen is among these because of its ease of ignition and explosive potential under certain conditions. This classification is important for selecting appropriate and safe equipment for use in areas where hydrogen is present.

Explanation

Gas groups are used in hazardous area classification, particularly in relation to electrical equipment used in environments where explosive atmospheres may be present. Group IIC is the gas group that includes gases with the highest level of hazard due to their low ignition energy, and hydrogen is among these because of its ease of ignition and explosive potential under certain conditions. This classification is important for selecting appropriate and safe equipment for use in areas where hydrogen is present.

47. A vapour will ignite without an ignition source when it reaches it's:

Flash point

Fire point

Ignition temperature

Boiling point

The ignition temperature refers to the minimum temperature at which a substance can ignite spontaneously without the need for an external ignition source. This means that once the vapour reaches its ignition temperature, it will ignite on its own, even without the presence of an ignition source such as a flame or spark. This is different from the flash point, which is the minimum temperature at which a substance can emit enough vapour to ignite when exposed to an ignition source. The fire point is the temperature at which the substance continues to burn after ignition has occurred. The boiling point, on the other hand, is the temperature at which a substance changes from a liquid to a gas state.

Explanation

The ignition temperature refers to the minimum temperature at which a substance can ignite spontaneously without the need for an external ignition source. This means that once the vapour reaches its ignition temperature, it will ignite on its own, even without the presence of an ignition source such as a flame or spark. This is different from the flash point, which is the minimum temperature at which a substance can emit enough vapour to ignite when exposed to an ignition source. The fire point is the temperature at which the substance continues to burn after ignition has occurred. The boiling point, on the other hand, is the temperature at which a substance changes from a liquid to a gas state.

48. What should the maximum earth impedance be for a Zenner barrier:

1MΩ

100Ω

10Ω

1Ω

The maximum earth impedance for a Zenner barrier should be 1Ω because a Zenner barrier is used in hazardous areas to prevent the transmission of electrical energy, and a low earth impedance ensures that any potential fault currents are quickly and safely dissipated to the earth. A higher earth impedance could result in the build-up of dangerous levels of electrical energy, increasing the risk of explosions or fires in the hazardous area.

Explanation

The maximum earth impedance for a Zenner barrier should be 1Ω because a Zenner barrier is used in hazardous areas to prevent the transmission of electrical energy, and a low earth impedance ensures that any potential fault currents are quickly and safely dissipated to the earth. A higher earth impedance could result in the build-up of dangerous levels of electrical energy, increasing the risk of explosions or fires in the hazardous area.

49. When multi-core cables with several pairs are to be used on apparatus requiring 3 cores. One pair is to be used, where can the third core be taken from:

Any spare core

A spare core from a pair where the other is used on another circuit

A 3 core cable must be run

Use one core from a spare pair and treat the other core as an unused core

The correct answer suggests that when multi-core cables with several pairs are used on apparatus requiring 3 cores, one can use one core from a spare pair and treat the other core as an unused core. This means that instead of running a separate 3 core cable or using any spare core, one can utilize the extra core from a spare pair and leave the remaining core unused. This allows for efficient utilization of resources and reduces the need for additional cables or spare cores.

Explanation

The correct answer suggests that when multi-core cables with several pairs are used on apparatus requiring 3 cores, one can use one core from a spare pair and treat the other core as an unused core. This means that instead of running a separate 3 core cable or using any spare core, one can utilize the extra core from a spare pair and leave the remaining core unused. This allows for efficient utilization of resources and reduces the need for additional cables or spare cores.

50. The T rating e.g. T5 marked on certified equipment indicates what

Will not reach the flashpoint of the gas in normal operation

Is deigned to reach the temperature of the T rating

Will not reach the ignition temperature of any dust or gas in normal operation

Will not exceed the temperature represented by T rating during normal or specified fault conditions

The T rating, such as T5 marked on certified equipment, indicates that the equipment will not exceed the temperature represented by the T rating during normal or specified fault conditions. This means that the equipment is designed to operate within a specific temperature range and will not overheat or reach temperatures that could cause ignition or flashpoint of any dust or gas in normal operation. The T rating provides assurance that the equipment is safe to use in potentially hazardous environments where there may be flammable substances present.

Explanation

The T rating, such as T5 marked on certified equipment, indicates that the equipment will not exceed the temperature represented by the T rating during normal or specified fault conditions. This means that the equipment is designed to operate within a specific temperature range and will not overheat or reach temperatures that could cause ignition or flashpoint of any dust or gas in normal operation. The T rating provides assurance that the equipment is safe to use in potentially hazardous environments where there may be flammable substances present.

51. Obstruction of a flamepath on the joints of Ex d enclosure requires a minimum clearance depending on the gas group, for a IIC gas minimum distance must be at least

40mm

50mm

10mm

30mm

The correct answer is 40mm. In hazardous environments, the joints of an Ex d enclosure need to have a minimum clearance to prevent obstruction of the flamepath. The clearance required depends on the gas group present. For a gas group IIC, the minimum distance should be at least 40mm. This ensures that there is enough space for the flame to travel through the joints without any obstruction, reducing the risk of explosion or ignition in the enclosure.

Explanation

The correct answer is 40mm. In hazardous environments, the joints of an Ex d enclosure need to have a minimum clearance to prevent obstruction of the flamepath. The clearance required depends on the gas group present. For a gas group IIC, the minimum distance should be at least 40mm. This ensures that there is enough space for the flame to travel through the joints without any obstruction, reducing the risk of explosion or ignition in the enclosure.

52. An explosive vapour is LIKELY present. What would be the zone classification:

Zone 0

Zone 1

Zone 2

Zone 20

The presence of an explosive vapor is indicated by the word "likely." Zone 1 classification is given to areas where explosive gases, vapors, or mist may be present occasionally during normal operation. Therefore, based on the given information, it can be inferred that there is a possibility of explosive vapor being present in the area, making Zone 1 the appropriate classification.

Explanation

The presence of an explosive vapor is indicated by the word "likely." Zone 1 classification is given to areas where explosive gases, vapors, or mist may be present occasionally during normal operation. Therefore, based on the given information, it can be inferred that there is a possibility of explosive vapor being present in the area, making Zone 1 the appropriate classification.

53. A motor has marked on the certification page 'T_E'. What does this indicate:

The maximum run time

The maximum disconnection time for stalled motor

The maximum temperature the motor will operate

The duty cycle of the motor

The marking "TE" on the certification page of a motor indicates the maximum disconnection time for a stalled motor. This means that if the motor becomes stalled or unable to rotate, it should be disconnected within the specified time to prevent any damage or overheating. The marking helps ensure the safe operation of the motor and prevents potential hazards.

Explanation

The marking "TE" on the certification page of a motor indicates the maximum disconnection time for a stalled motor. This means that if the motor becomes stalled or unable to rotate, it should be disconnected within the specified time to prevent any damage or overheating. The marking helps ensure the safe operation of the motor and prevents potential hazards.

54. In which of the following zones is an explosive gas/air mixture likely to occur in normal operations

Zone 21

Zone 0

Zone 2

Zone 1

An explosive gas/air mixture is likely to occur in Zone 1 during normal operations. Zone 1 is a hazardous area where flammable gases, vapors, or liquids are present occasionally during normal operations. It is important to take appropriate precautions and use equipment that is specifically designed for use in this zone to prevent any potential explosions or accidents.

Explanation

An explosive gas/air mixture is likely to occur in Zone 1 during normal operations. Zone 1 is a hazardous area where flammable gases, vapors, or liquids are present occasionally during normal operations. It is important to take appropriate precautions and use equipment that is specifically designed for use in this zone to prevent any potential explosions or accidents.

55. What is the minimum interval between inspections for portable equipment?

12 months

6 months

3 years

When faulty

The minimum interval between inspections for portable equipment is 12 months. This means that the equipment should be inspected at least once every year to ensure its safety and proper functioning. Regular inspections help identify any faults or issues with the equipment and allow for timely maintenance or repairs. By conducting inspections every 12 months, potential risks and hazards can be minimized, ensuring the equipment remains in good condition and meets safety standards.

Explanation

The minimum interval between inspections for portable equipment is 12 months. This means that the equipment should be inspected at least once every year to ensure its safety and proper functioning. Regular inspections help identify any faults or issues with the equipment and allow for timely maintenance or repairs. By conducting inspections every 12 months, potential risks and hazards can be minimized, ensuring the equipment remains in good condition and meets safety standards.

56. ATEX certified equipment will have the following mark:

A crown inscribed with FLP

A hexagon inscribed IEC

A hexagon inscribed Ex

The CE marking

The correct answer is a hexagon inscribed Ex. ATEX certified equipment is used in potentially explosive atmospheres, and the hexagon inscribed with Ex indicates that the equipment meets the requirements of the ATEX directive for explosive atmospheres. The Ex symbol stands for "explosive atmosphere" and is recognized internationally as a symbol for equipment that is safe to use in such environments.

Explanation

The correct answer is a hexagon inscribed Ex. ATEX certified equipment is used in potentially explosive atmospheres, and the hexagon inscribed with Ex indicates that the equipment meets the requirements of the ATEX directive for explosive atmospheres. The Ex symbol stands for "explosive atmosphere" and is recognized internationally as a symbol for equipment that is safe to use in such environments.

57. What is required to undertake a VISUAL inspection of Ex d e n equipment

Lamp ratings

Apparatus circuit identification is available

Flange faces are clean and undamaged

The type of cable used

To undertake a visual inspection of Ex d e n equipment, it is necessary to have apparatus circuit identification available. This means that the equipment should be properly labeled or marked with circuit identification information. This is important for safety and maintenance purposes as it allows for easy identification and troubleshooting of circuits within the equipment. Without proper circuit identification, it would be difficult to conduct a thorough visual inspection and ensure the equipment is in proper working condition.

Explanation

To undertake a visual inspection of Ex d e n equipment, it is necessary to have apparatus circuit identification available. This means that the equipment should be properly labeled or marked with circuit identification information. This is important for safety and maintenance purposes as it allows for easy identification and troubleshooting of circuits within the equipment. Without proper circuit identification, it would be difficult to conduct a thorough visual inspection and ensure the equipment is in proper working condition.

58. An IS barrier is required to maintain safety even under fault conditions, On handover the permitted number of faults is?

One

Two

Three

None

An IS barrier is designed to ensure safety even in the presence of faults. It acts as a protective measure to prevent any hazardous conditions from occurring. Therefore, the permitted number of faults in an IS barrier is none. This means that the barrier should not allow any faults to compromise the safety of the system.

Explanation

An IS barrier is designed to ensure safety even in the presence of faults. It acts as a protective measure to prevent any hazardous conditions from occurring. Therefore, the permitted number of faults in an IS barrier is none. This means that the barrier should not allow any faults to compromise the safety of the system.

59. In which of the following zones is an explosive gas/air mixture unlikely to occur in normal operations but if it does, will persist for short periods only

Zone 2

Zone 1

Zone 0

Zone 3

Zone 2 is an area where an explosive gas/air mixture is unlikely to occur in normal operations. However, if it does occur, it will only persist for short periods of time. This means that the concentration of the explosive gas/air mixture in Zone 2 is not high enough to sustain combustion for extended periods. Therefore, even if an explosive gas/air mixture is present in Zone 2, the risk of explosion is relatively low compared to other zones.

Explanation

Zone 2 is an area where an explosive gas/air mixture is unlikely to occur in normal operations. However, if it does occur, it will only persist for short periods of time. This means that the concentration of the explosive gas/air mixture in Zone 2 is not high enough to sustain combustion for extended periods. Therefore, even if an explosive gas/air mixture is present in Zone 2, the risk of explosion is relatively low compared to other zones.

60. What type of gland would be installed in an enclosure marked Ex d [ia]

A flameproof gland suitable for both cable and enclosure

An increased safety gland suitable for the cable

A gland certified as Ex i and suitable for the cable

A standard industrial IP 54 gland suitable for the cable

The correct answer is a flameproof gland suitable for both cable and enclosure. This type of gland is designed to prevent the entry of flammable gases or vapors into the enclosure, thus reducing the risk of explosion. It is suitable for use in hazardous environments where there is a potential for the presence of explosive atmospheres. The flameproof gland ensures that the cable and enclosure are effectively sealed, providing a high level of protection against ignition sources.

Explanation

The correct answer is a flameproof gland suitable for both cable and enclosure. This type of gland is designed to prevent the entry of flammable gases or vapors into the enclosure, thus reducing the risk of explosion. It is suitable for use in hazardous environments where there is a potential for the presence of explosive atmospheres. The flameproof gland ensures that the cable and enclosure are effectively sealed, providing a high level of protection against ignition sources.

61. According to the IEC 60079 where can Ex n equipment be installed:

EPL Gb, Category 2G area

EPL Ga, Category 1G area

EPL Gc, category 3G area

EPL Da, Category 1D area

Ex n equipment can be installed in EPL Gc, category 3G areas according to IEC 60079. This means that the equipment is suitable for use in areas where there is a risk of the presence of flammable gases, vapors, or mists, but the likelihood of their occurrence is less frequent or for shorter durations compared to EPL Ga and EPL Gb areas. The equipment is designed to prevent the ignition of explosive atmospheres by limiting the energy and surface temperature that could cause ignition.

Explanation

Ex n equipment can be installed in EPL Gc, category 3G areas according to IEC 60079. This means that the equipment is suitable for use in areas where there is a risk of the presence of flammable gases, vapors, or mists, but the likelihood of their occurrence is less frequent or for shorter durations compared to EPL Ga and EPL Gb areas. The equipment is designed to prevent the ignition of explosive atmospheres by limiting the energy and surface temperature that could cause ignition.

62. Cable tray is to be installed in an area requiring EPL Gc. What are the limitations

Cannot contain more than 7.5% Aluminium

Cannot contain more than 7.5% Magnesium and Titanium

Cannot contain more than 7.5% Magnesium, Titanium and Zirconium

No Limitations

The correct answer is "No Limitations". This means that there are no restrictions or limitations on the composition of the cable tray in terms of the percentage of aluminium, magnesium, titanium, and zirconium it can contain. The cable tray can be installed in an area requiring EPL Gc without any specific limitations on its material composition.

Explanation

The correct answer is "No Limitations". This means that there are no restrictions or limitations on the composition of the cable tray in terms of the percentage of aluminium, magnesium, titanium, and zirconium it can contain. The cable tray can be installed in an area requiring EPL Gc without any specific limitations on its material composition.

63. What is the minimum CSA when using a single earthing conductor for a Zener barrier:

1.5mm2

2.5mm2

4.0mm2

6.0mm2

The minimum CSA (cross-sectional area) required for a single earthing conductor in a Zener barrier is 4.0mm2. This indicates that a larger cross-sectional area is necessary to ensure proper grounding and safety in the system. A larger CSA helps to reduce resistance and increase the current-carrying capacity of the conductor, which is important for effective earthing.

Explanation

The minimum CSA (cross-sectional area) required for a single earthing conductor in a Zener barrier is 4.0mm2. This indicates that a larger cross-sectional area is necessary to ensure proper grounding and safety in the system. A larger CSA helps to reduce resistance and increase the current-carrying capacity of the conductor, which is important for effective earthing.

64. Which of the following is the primary purpose of conducting a hazard assessment in an industrial setting?

To increase production efficiency

To identify and eliminate potential safety risks

To train employees on the use of new machinery

To assess the quality of finished products

The primary purpose of conducting a hazard assessment in an industrial setting is to identify and eliminate potential safety risks. This process involves evaluating the workplace for hazards that could cause injury or harm to employees, and implementing controls or corrective actions to reduce or eliminate these risks, thereby ensuring a safer working environment.

Explanation

The primary purpose of conducting a hazard assessment in an industrial setting is to identify and eliminate potential safety risks. This process involves evaluating the workplace for hazards that could cause injury or harm to employees, and implementing controls or corrective actions to reduce or eliminate these risks, thereby ensuring a safer working environment.

65. What is the international abbreviation that corresponds to ATEX

API

TAT

EPL

IEC

ATEX stands for Atmosphères Explosibles, which is a European directive regulating equipment used in potentially explosive atmospheres. The International Electrotechnical Commission (IEC) is a global organization that sets international standards for electrical, electronic, and related technologies. Since ATEX is a European directive, it is not an international abbreviation. Therefore, the correct answer is IEC, as it represents the international standards organization.

Explanation

ATEX stands for Atmosphères Explosibles, which is a European directive regulating equipment used in potentially explosive atmospheres. The International Electrotechnical Commission (IEC) is a global organization that sets international standards for electrical, electronic, and related technologies. Since ATEX is a European directive, it is not an international abbreviation. Therefore, the correct answer is IEC, as it represents the international standards organization.

66. What equipment can be installed in a Hydrogen environment requiring EPL Gc, Category 3G

Ex d IIA T6

Ex d IIB T3

Ex n II T3

Ex e IIA T4

The correct answer is Ex n II T3. This equipment can be installed in a Hydrogen environment requiring EPL Gc, Category 3G. Ex n refers to non-sparking electrical equipment, which is suitable for use in hazardous areas with flammable gases or vapors. II indicates that the equipment is suitable for use in Zone 2, where explosive atmospheres may occasionally occur. T3 indicates that the equipment can operate at a maximum surface temperature of 200°C, making it suitable for use in environments with hydrogen.

Explanation

The correct answer is Ex n II T3. This equipment can be installed in a Hydrogen environment requiring EPL Gc, Category 3G. Ex n refers to non-sparking electrical equipment, which is suitable for use in hazardous areas with flammable gases or vapors. II indicates that the equipment is suitable for use in Zone 2, where explosive atmospheres may occasionally occur. T3 indicates that the equipment can operate at a maximum surface temperature of 200°C, making it suitable for use in environments with hydrogen.

67. If in a pressurised control room in an EPL Gc area the pressure fails. What are the requirements:

No action required

Alarm operates, isolate all Ex equipment

Alarm operates, take immediate action to restore the system

Alarm operates and all equipment is switched off

In a pressurized control room in an EPL Gc area, if the pressure fails, it is crucial to take immediate action to restore the system. The alarm should operate to alert the personnel about the pressure failure. This prompt response is necessary to prevent any potential hazards or further damage to the equipment or the control room. By taking immediate action, the system can be restored, and the pressure can be brought back to the required level, ensuring the safety and functionality of the control room.

Explanation

In a pressurized control room in an EPL Gc area, if the pressure fails, it is crucial to take immediate action to restore the system. The alarm should operate to alert the personnel about the pressure failure. This prompt response is necessary to prevent any potential hazards or further damage to the equipment or the control room. By taking immediate action, the system can be restored, and the pressure can be brought back to the required level, ensuring the safety and functionality of the control room.

68. IS cables with screens will have sheathing capable of withstanding one of the following test voltages

500v AC and 750v DC

500v AC or 750v DC

1000v

Double the working voltage

Cables with screens are designed to provide protection against electromagnetic interference. The sheathing of these cables needs to be able to withstand certain test voltages. The correct answer states that cables with screens will have sheathing capable of withstanding either 500v AC or 750v DC. This means that the sheathing of these cables should be able to handle either of these voltages during testing.

Explanation

Cables with screens are designed to provide protection against electromagnetic interference. The sheathing of these cables needs to be able to withstand certain test voltages. The correct answer states that cables with screens will have sheathing capable of withstanding either 500v AC or 750v DC. This means that the sheathing of these cables should be able to handle either of these voltages during testing.

69. Equipment marked Ex e IIC T5 can be used in?

Area requiring Gc (Cat3G) and IIB gases only

Any Zone with IIA & IIB gases

Any Zone & Any gas group

Areas Gb, Gc (Cat 2G,3G) with IIC, IIB & IIA gas groups

The equipment marked Ex e IIC T5 can be used in areas Gb, Gc (Cat 2G,3G) with IIC, IIB & IIA gas groups. This means that the equipment is suitable for use in hazardous locations where there may be the presence of gases from all three gas groups, namely IIA, IIB, and IIC. It can be used in zones Gb and Gc, which are areas classified as having a higher level of gas presence and potential explosion risk. The equipment is also certified for use in both Category 2G and Category 3G hazardous areas, indicating its suitability for a wide range of hazardous environments.

Explanation

The equipment marked Ex e IIC T5 can be used in areas Gb, Gc (Cat 2G,3G) with IIC, IIB & IIA gas groups. This means that the equipment is suitable for use in hazardous locations where there may be the presence of gases from all three gas groups, namely IIA, IIB, and IIC. It can be used in zones Gb and Gc, which are areas classified as having a higher level of gas presence and potential explosion risk. The equipment is also certified for use in both Category 2G and Category 3G hazardous areas, indicating its suitability for a wide range of hazardous environments.

70. Isolation requires that the neutral conductor:

Remains connected

Is easily disconnected

Is fused

Is of the colour blue

For isolation purposes, it is important that the neutral conductor can be easily disconnected to ensure complete electrical isolation of a circuit. This is necessary for safety during maintenance and to ensure that there is no unintended flow of current when the circuit is supposed to be isolated.

Explanation

For isolation purposes, it is important that the neutral conductor can be easily disconnected to ensure complete electrical isolation of a circuit. This is necessary for safety during maintenance and to ensure that there is no unintended flow of current when the circuit is supposed to be isolated.

71. What is required to undertake a VISUAL inspection of an Ex e luminaire?

Details of the rating of the lamp

An area classification drawing

Tools and equipment

Access equipment

A visual inspection of an Ex e luminaire involves checking for visible signs of damage, wear, or incorrect installation that could compromise safety. The area classification drawing is crucial because it provides information about the specific hazardous area where the luminaire is installed, ensuring that the correct equipment and safety measures are in place for the inspection.

Details of the rating of the lamp: While important for ensuring compatibility and safety, this information is typically verified during the installation or maintenance phases rather than a basic visual inspection.

Tools and equipment: Visual inspections generally do not require specialized tools and equipment beyond what is necessary to safely access and observe the luminaire.

Access equipment: This is necessary only if the luminaire is installed in a location that is difficult to reach, but it is not specifically required for the inspection itself.

Explanation

A visual inspection of an Ex e luminaire involves checking for visible signs of damage, wear, or incorrect installation that could compromise safety. The area classification drawing is crucial because it provides information about the specific hazardous area where the luminaire is installed, ensuring that the correct equipment and safety measures are in place for the inspection.

Details of the rating of the lamp: While important for ensuring compatibility and safety, this information is typically verified during the installation or maintenance phases rather than a basic visual inspection.

Tools and equipment: Visual inspections generally do not require specialized tools and equipment beyond what is necessary to safely access and observe the luminaire.

Access equipment: This is necessary only if the luminaire is installed in a location that is difficult to reach, but it is not specifically required for the inspection itself.

72. A close inspection of an IS installation would reveal that?

Electrical connections are tight

Cable screens are earthed

Installation is clearly labelled

There are no unauthorised modifications

The correct answer is "installation is clearly labelled". This means that when inspecting an IS (Intrinsically Safe) installation, one would find that all the components and equipment are clearly marked or labeled. This is important for safety and compliance purposes as it helps identify and locate specific devices, circuits, or areas within the installation. Clear labeling also aids in troubleshooting, maintenance, and proper operation of the IS system.

Explanation

The correct answer is "installation is clearly labelled". This means that when inspecting an IS (Intrinsically Safe) installation, one would find that all the components and equipment are clearly marked or labeled. This is important for safety and compliance purposes as it helps identify and locate specific devices, circuits, or areas within the installation. Clear labeling also aids in troubleshooting, maintenance, and proper operation of the IS system.

73. What location can Ex n equipment be installed

EPL Ga, Gb and Gc Categories 1G, 2G and 3G

EPL Ga and Gb Categories 1G and 2G

EPL Gb and Gc Categories 2G and 3G

EPL Gc Category 3G only

Ex n equipment can only be installed in locations that have EPL Gc Category 3G.

Explanation

Ex n equipment can only be installed in locations that have EPL Gc Category 3G.

74. Under ATEX 137 where can Category 2 equipment be used:

Zones 0, 20

Zones 1, 21 and lesser zones

Zones 2, 22 only

Zones 20, 21 and 22 only

Category 2 equipment can be used in Zones 1, 21 and lesser zones. This means that the equipment is suitable for use in areas where an explosive atmosphere is likely to occur occasionally or infrequently, and for short durations. Zones 1 and 21 are areas where explosive atmospheres are likely to occur occasionally, while lesser zones refer to areas where explosive atmospheres are less likely to occur. Therefore, Category 2 equipment provides a level of protection suitable for these specific hazardous areas.

Explanation

Category 2 equipment can be used in Zones 1, 21 and lesser zones. This means that the equipment is suitable for use in areas where an explosive atmosphere is likely to occur occasionally or infrequently, and for short durations. Zones 1 and 21 are areas where explosive atmospheres are likely to occur occasionally, while lesser zones refer to areas where explosive atmospheres are less likely to occur. Therefore, Category 2 equipment provides a level of protection suitable for these specific hazardous areas.

75. The comparison between Ex nL and EXic is correctly stated by which of the following statements

Both may be used in Zones 0,1 & 2

Both may be used in Zone 2 only

Ex nL used in Zones 0,1&2, Ex ic in Zone 2 only

Ex ic used in Zones 0,1&2, Ex nL in Zone 2 only

Both Ex nL and EXic can be used in Zone 2 only.

Explanation

Both Ex nL and EXic can be used in Zone 2 only.

76. A steel Ex e enclosure has clearance holes, what is the minimum requirement for installing an SWA cable

Fit Gland, internal IP washer, serrated washer and lock nut

Fit gland, earth tag, serrated washer and internal locknut

Fit gland, external IP washer, internal serrated washer and locknut

Fit gland external IP washer and internal locknut

The correct answer is to fit gland, external IP washer, internal serrated washer, and locknut. This combination ensures a secure and watertight connection for the SWA cable in the steel Ex e enclosure. The external IP washer provides additional protection against water ingress, while the internal serrated washer and locknut help to secure the cable and prevent it from loosening or coming out of the enclosure.

Explanation

The correct answer is to fit gland, external IP washer, internal serrated washer, and locknut. This combination ensures a secure and watertight connection for the SWA cable in the steel Ex e enclosure. The external IP washer provides additional protection against water ingress, while the internal serrated washer and locknut help to secure the cable and prevent it from loosening or coming out of the enclosure.

77. Cable Gland marked with a Suffix 'X' may only be used with?

Portable equipment with additional clamping on the cable

Fixed equipment with additional clamping of the cable

An enclosure also marked with an X

Fixed equipment

A cable gland marked with a suffix 'X' may only be used with fixed equipment that has additional clamping of the cable. This indicates that the cable gland is specifically designed for use in fixed equipment where the cable needs to be securely clamped in place. The 'X' suffix serves as a distinguishing feature to ensure that the cable gland is not used in other applications where it may not be suitable.

Explanation

A cable gland marked with a suffix 'X' may only be used with fixed equipment that has additional clamping of the cable. This indicates that the cable gland is specifically designed for use in fixed equipment where the cable needs to be securely clamped in place. The 'X' suffix serves as a distinguishing feature to ensure that the cable gland is not used in other applications where it may not be suitable.

78. In electrical installations, what is the purpose of a residual current device (RCD)?

To regulate the flow of voltage in a circuit

To protect against overload conditions

To detect and interrupt abnormal electrical currents

To control the frequency of alternating current fluctuations

A residual current device (RCD) is a safety device designed to quickly detect and interrupt abnormal electrical currents, such as those caused by leakage or fault currents, to prevent electric shock or fire hazards.

Explanation

A residual current device (RCD) is a safety device designed to quickly detect and interrupt abnormal electrical currents, such as those caused by leakage or fault currents, to prevent electric shock or fire hazards.

79. An Ex de motor with an Ex e JB installed in 2005, which gland achieves minimum installation requirement

Uncertified gland which meets the IP and impact requirement

E1W Ex e gland

E1W Ex d gland

Ex de gland

The correct answer is the uncertified gland which meets the IP and impact requirement. This gland is able to meet the minimum installation requirement because it meets the necessary IP (Ingress Protection) rating, which indicates its ability to resist the entry of solid objects and liquids. Additionally, it also meets the impact requirement, ensuring its durability and ability to withstand external forces. Although it is uncertified, it still fulfills the necessary criteria for installation in this specific scenario.

Explanation

The correct answer is the uncertified gland which meets the IP and impact requirement. This gland is able to meet the minimum installation requirement because it meets the necessary IP (Ingress Protection) rating, which indicates its ability to resist the entry of solid objects and liquids. Additionally, it also meets the impact requirement, ensuring its durability and ability to withstand external forces. Although it is uncertified, it still fulfills the necessary criteria for installation in this specific scenario.

80. An item of equipment marked Ex ib IIC T6 may be used in an area requiring:

EPL Ga, Gb and Gc; Categories 1G, 2G and 3G; gas group IIA and IIB

EPL Ga and Gb; Categories 1G and 2G; gas group IIB and IIC

EPL Gb and Gc; Categories 2G and 3G; gas group IIC

Any location and gas group

The item of equipment marked Ex ib IIC T6 can be used in areas requiring EPL Gb and Gc, Categories 2G and 3G, and gas group IIC. This means that the equipment is suitable for use in locations where there is a risk of explosive gas atmospheres, specifically in zones Gb and Gc. It can be used in both Category 2G and Category 3G areas, which indicate the level of protection required. Finally, it is suitable for use with gas groups IIC, which includes gases such as hydrogen, ethylene, and acetylene.

Explanation

The item of equipment marked Ex ib IIC T6 can be used in areas requiring EPL Gb and Gc, Categories 2G and 3G, and gas group IIC. This means that the equipment is suitable for use in locations where there is a risk of explosive gas atmospheres, specifically in zones Gb and Gc. It can be used in both Category 2G and Category 3G areas, which indicate the level of protection required. Finally, it is suitable for use with gas groups IIC, which includes gases such as hydrogen, ethylene, and acetylene.

81. Equipment is marked Ex d [ib]. Does this indicate:

The equipment is intrinsically safe

That the equipment can be used on IS circuits only

That the equipment is part of an intrinsically safe system

That the enclosure contains associated IS equipment

The marking "Ex d [ib]" indicates that the equipment is designed to be used in a hazardous environment where explosive gases or vapors may be present. The "Ex d" marking refers to a type of explosion protection method known as flameproof or explosion-proof, which means that the enclosure is designed to contain any explosion that may occur within it. The "[ib]" marking indicates that the equipment is intrinsically safe, meaning that it is designed to prevent the release of enough energy to ignite a hazardous atmosphere. Therefore, the correct answer is that the enclosure contains associated intrinsically safe equipment.

Explanation

The marking "Ex d [ib]" indicates that the equipment is designed to be used in a hazardous environment where explosive gases or vapors may be present. The "Ex d" marking refers to a type of explosion protection method known as flameproof or explosion-proof, which means that the enclosure is designed to contain any explosion that may occur within it. The "[ib]" marking indicates that the equipment is intrinsically safe, meaning that it is designed to prevent the release of enough energy to ignite a hazardous atmosphere. Therefore, the correct answer is that the enclosure contains associated intrinsically safe equipment.

82. What does the marking [Ex ib] IIC on IS equipment indicate?

It is intrinsically safe and for use with IIC gases

It is intrinsically safe and can be installed anywhere

It may only be installed in a non hazardous area

It is equipment associated with IS circuits

The marking "[Ex ib] IIC" on IS equipment indicates that it is intrinsically safe and suitable for use in hazardous areas where flammable gases or vapors of Category IIC may be present. Intrinsically safe equipment is designed to prevent ignition of flammable atmospheres by limiting the electrical energy available. Category IIC gases are the most easily ignitable, including hydrogen, acetylene, and carbon disulfide.

Explanation

The marking "[Ex ib] IIC" on IS equipment indicates that it is intrinsically safe and suitable for use in hazardous areas where flammable gases or vapors of Category IIC may be present. Intrinsically safe equipment is designed to prevent ignition of flammable atmospheres by limiting the electrical energy available. Category IIC gases are the most easily ignitable, including hydrogen, acetylene, and carbon disulfide.

83. In an area requiring EPL Gb Category 2 where the equipment does not contain sparking capable apparatus. What level of protection is required:

Px

Pz

Py

No protection required

In hazardous areas classified with EPL (Equipment Protection Level) Gb Category 2, where there are no sparking capable apparatus in the equipment, the level of protection required is "Py." This classification indicates that the equipment is designed to be inherently safe and doesn't contain potential sources of ignition that could lead to the formation of explosive atmospheres.

Explanation

In hazardous areas classified with EPL (Equipment Protection Level) Gb Category 2, where there are no sparking capable apparatus in the equipment, the level of protection required is "Py." This classification indicates that the equipment is designed to be inherently safe and doesn't contain potential sources of ignition that could lead to the formation of explosive atmospheres.

84. Which area classification requires the installation of Ex ia equipment?

EPL Ga, Gb or Gc - categories 1G, 2G or 3G

EPL Gb or Gc - Categories 2G or 3G

EPL Gc - Category 3G only

EPL Ga - Category 1G only

The correct answer states that for an area that requires Ex ia equipment to be installed, the possible area classification could be EPL Ga, Gb or Gc - categories 1G, 2G or 3G. This means that the equipment can be installed in areas classified as Ga, Gb, or Gc, and can be used for all three categories of hazardous gases - 1G, 2G, or 3G.

Explanation

The correct answer states that for an area that requires Ex ia equipment to be installed, the possible area classification could be EPL Ga, Gb or Gc - categories 1G, 2G or 3G. This means that the equipment can be installed in areas classified as Ga, Gb, or Gc, and can be used for all three categories of hazardous gases - 1G, 2G, or 3G.

85. What is the primary safety protocol when operating heavy machinery at Hornbill Industrial Training?

Always wear protective gear, including gloves and goggles.

Ensure the machinery is turned off before leaving it unattended.

Conduct a thorough inspection of the machinery before each use.

Only operate machinery for which you have received specific training and certification.

At Hornbill Industrial Training, a key safety protocol is ensuring that all operators are specifically trained and certified for the machinery they are assigned to operate. This ensures that operators are familiar with the particular safety and operational features of the equipment, reducing the risk of accidents due to unfamiliarity or improper use.

Explanation

At Hornbill Industrial Training, a key safety protocol is ensuring that all operators are specifically trained and certified for the machinery they are assigned to operate. This ensures that operators are familiar with the particular safety and operational features of the equipment, reducing the risk of accidents due to unfamiliarity or improper use.

86. IS and non-IS cables are to be installed on site. What are the requirements:

All cables are to be run on separate cable tray

All cables can be run with any other cables

The IS or non-IS cables needs to be armoured, metal sheathed or screened

Both the IS and non-IS needs to be armoured, metal sheathed and screened

The requirement for the cables is that they need to be either armoured, metal sheathed, or screened, regardless of whether they are IS or non-IS cables. This means that both types of cables must have one or more of these protective features in order to meet the installation requirements.

Explanation

The requirement for the cables is that they need to be either armoured, metal sheathed, or screened, regardless of whether they are IS or non-IS cables. This means that both types of cables must have one or more of these protective features in order to meet the installation requirements.

87. If the area classification indicates Ga equipment is required in a Zone 1 area, why is this?

This is a mistake

The risk assessment has found a higher than normal consequence of ignition

The risk assessment has found a lower than normal consequence of ignition

The risk assessment has found a higher than normal risk of ignition

The correct answer is "the risk assessment has found a higher than normal consequence of ignition." This means that the risk assessment has determined that if an ignition were to occur in this Zone 1 area, the consequences would be more severe than usual. Therefore, Ga equipment, which is specifically designed to prevent or mitigate the risk of ignition, is required in this area to minimize the potential consequences.

Explanation

The correct answer is "the risk assessment has found a higher than normal consequence of ignition." This means that the risk assessment has determined that if an ignition were to occur in this Zone 1 area, the consequences would be more severe than usual. Therefore, Ga equipment, which is specifically designed to prevent or mitigate the risk of ignition, is required in this area to minimize the potential consequences.

88. Which Sub-division gas group does Acetylene fall?

IIA

IIB

IIC

Acetylene falls under the Sub-division gas group IIC. The IIC group includes gases that are capable of forming explosive mixtures with air, but require a higher energy input or a higher temperature to initiate combustion compared to gases in the IIA and IIB groups. Acetylene is a highly flammable gas that can form explosive mixtures with air, making it a part of the IIC group.

Explanation

Acetylene falls under the Sub-division gas group IIC. The IIC group includes gases that are capable of forming explosive mixtures with air, but require a higher energy input or a higher temperature to initiate combustion compared to gases in the IIA and IIB groups. Acetylene is a highly flammable gas that can form explosive mixtures with air, making it a part of the IIC group.

89. A flameproof motor installed in 2005 has an Ex e terminal box. What is the gland selection:

Ex d gland

Uncertified IP 68 gland

Ex i gland

E1W gland

For a flameproof motor with an Ex e terminal box, the appropriate gland selection is an E1W gland. This type of gland is suitable for use with Ex e equipment and provides effective sealing against the ingress of moisture and particles, ensuring the safety and integrity of the electrical installation.

Explanation

For a flameproof motor with an Ex e terminal box, the appropriate gland selection is an E1W gland. This type of gland is suitable for use with Ex e equipment and provides effective sealing against the ingress of moisture and particles, ensuring the safety and integrity of the electrical installation.

90. In enclosures marked with which certification can uncertified power supplies for Ex ia equipment be installed?

Ex n

Ex e

Ex i

Ex p

Ex e enclosures are designed for installation in Ex Zones 1 and 2. They are used for the intrinsically safe supply of power to field devices. Therefore, uncertified power supplies for Ex ia equipment could be installed in Ex e enclosures.

Explanation

Ex e enclosures are designed for installation in Ex Zones 1 and 2. They are used for the intrinsically safe supply of power to field devices. Therefore, uncertified power supplies for Ex ia equipment could be installed in Ex e enclosures.