Hornbill Industrial Training Mock Compex Online Exam
Hornbill Industrial Training provides CompEx training and certification, including CompEx Gas/Vapour, Dust, Mechanical, Refresher, Responsible Persons and Foundation courses.
This is a Hornbill Industrial Training Mock CompEx Online Exam.
Questions and Answers
- 1.
The Atex 95 Directive is concerned with:
- A.
The health and safety of workers
- B.
The electricity at work act
- C.
The design and trade of explosion protection equipment
- D.
Standardisation of electrical voltages
Correct Answer
C. The design and trade of explosion protection equipmentExplanation
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.Rate this question:
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- 2.
ATEX divides equipment into groups and categories. What are they?
- A.
Group I - categories 1,2,3
- B.
Group II - Categories 1,2,3
- C.
Group III - Categories 1,2,3
- D.
Group IIII - Categories 1,2,3
Correct Answer
B. Group II - Categories 1,2,3Explanation
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.Rate this question:
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- 3.
IEC divides equipment into Equipment Protection Levels EPLs. What are they?
- A.
Ga, Gb, Gc
- B.
Gd, Ge, Gn
- C.
Gia, Gib, Gic
- D.
Gx, Gy, Gz
Correct Answer
A. Ga, Gb, GcExplanation
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.Rate this question:
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- 4.
Which is the ATEX installation standard?
- A.
IEC 60079-0
- B.
IEC 60079-10
- C.
IEC 60079-14
- D.
IEC 60079-17
Correct Answer
C. IEC 60079-14Explanation
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.Rate this question:
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- 5.
Which gas group includes Hydrogen:
- A.
I
- B.
IIA
- C.
IIB
- D.
IIC
Correct Answer
A. IExplanation
Hydrogen is classified under Gas Group I. It is the first element in the periodic table and is grouped with alkali metals. Hydrogen is a colorless, odorless gas that is highly reactive and flammable. It is commonly found in compounds such as water and hydrocarbons, and plays a vital role in various industrial processes.Rate this question:
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- 6.
Which of the following is not needed for combustion to occur:
- A.
Ignition source
- B.
Fuel supply
- C.
Enclosure
- D.
Oxygen
Correct Answer
C. EnclosureExplanation
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.Rate this question:
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- 7.
A vapour will ignite without an ignition source when it reaches it's:
- A.
Flash point
- B.
Fire point
- C.
Ignition temperature
- D.
Boiling point
Correct Answer
C. Ignition temperatureExplanation
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.Rate this question:
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- 8.
What is the design ambient temperature if not marked on the equipment:
- A.
-10oC to +20oC
- B.
-20oC to +40oC
- C.
-30oC to +60oC
- D.
-40oC to +80oC
Correct Answer
B. -20oC to +40oCExplanation
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.Rate this question:
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- 9.
What does the T rating of equipment represent?
- A.
The equipment will reach this temperature in normal operation
- B.
The equipment will reach it's flash point in normal operation
- C.
The relevant surfaces of the equipment will not reach this temperature in normal operation
- D.
The equipment will exceed the temperature rating in normal operation
Correct Answer
C. The relevant surfaces of the equipment will not reach this temperature in normal operationExplanation
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.Rate this question:
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- 10.
An explosive vapour is LIKELY present. What would be the zone classification:
- A.
Zone 0
- B.
Zone 1
- C.
Zone 2
- D.
Zone 20
Correct Answer
B. Zone 1Explanation
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.Rate this question:
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- 11.
On an area classification drawing what would represent Zone 1:
- A.
Circles
- B.
Cross hatching
- C.
As symbols shown on the drawing
- D.
Slanted lines
Correct Answer
C. As symbols shown on the drawingExplanation
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.Rate this question:
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- 12.
What is the international abbreviation that corresponds to ATEX
- A.
API
- B.
TAT
- C.
EPL
- D.
IEC
Correct Answer
D. IECExplanation
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.Rate this question:
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- 13.
What letters are used by the IEC for Equipment protection levels:
- A.
A,b,c
- B.
B,d,c
- C.
W,x,y
- D.
C,B,E
Correct Answer
A. A,b,cExplanation
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.Rate this question:
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- 14.
Under ATEX 137 where can Category 2 equipment be used:
- A.
Zones 0, 20
- B.
Zones 1, 21 and lesser zones
- C.
Zones 2, 22 only
- D.
Zones 20, 21 and 22 only
Correct Answer
B. Zones 1, 21 and lesser zonesExplanation
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.Rate this question:
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- 15.
According to the IEC 60079 where can Ex n equipment be installed:
- A.
EPL Gb, Category 2G area
- B.
EPL Ga, Category 1G area
- C.
EPL Gc, category 3G area
- D.
EPL Da, Category 1D area
Correct Answer
C. EPL Gc, category 3G areaExplanation
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.Rate this question:
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- 16.
Which protection types can be used in an area requiring EPL Ga and category 1G
- A.
Ex d
- B.
Ex e
- C.
Ex ia
- D.
Ex ib
Correct Answer
C. Ex iaExplanation
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.Rate this question:
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- 17.
Which area classification requires the installation of Ex ia equipment?
- A.
EPL Ga, Gb or Gc - categories 1G, 2G or 3G
- B.
EPL Gb or Gc - Categories 2G or 3G
- C.
EPL Gc - Category 3G only
- D.
EPL Ga - Category 1G only
Correct Answer
A. EPL Ga, Gb or Gc - categories 1G, 2G or 3GExplanation
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.Rate this question:
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- 18.
What equipment can be installed in a Hydrogen environment requiring EPL Gc, Category 3G
- A.
Ex d IIA T6
- B.
Ex d IIB T3
- C.
Ex n II T3
- D.
Ex e IIA T4
Correct Answer
C. Ex n II T3Explanation
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.Rate this question:
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- 19.
What location can Ex n equipment be installed
- A.
EPL Ga, Gb and Gc Categories 1G, 2G and 3G
- B.
EPL Ga and Gb Categories 1G and 2G
- C.
EPL Gb and Gc Categories 2G and 3G
- D.
EPL Gc Category 3G only
Correct Answer
D. EPL Gc Category 3G onlyExplanation
Ex n equipment can only be installed in locations that have EPL Gc Category 3G.Rate this question:
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- 20.
An item of equipment marked Ex ib IIC T6 may be used in an area requiring:
- A.
EPL Ga, Gb and Gc; Categories 1G, 2G and 3G; gas group IIA and IIB
- B.
EPL Ga and Gb; Categories 1G and 2G; gas group IIB and IIC
- C.
EPL Gb and Gc; Categories 2G and 3G; gas group IIC
- D.
Any location and gas group
Correct Answer
C. EPL Gb and Gc; Categories 2G and 3G; gas group IICExplanation
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.Rate this question:
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- 21.
Cable glands installed into Ex n boxes after 2007 are required to be:
- A.
Certified Ex d gland
- B.
Certified Ex e gland
- C.
Certified Barrier gland
- D.
Certified to IEC 60079
Correct Answer
D. Certified to IEC 60079Explanation
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.Rate this question:
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- 22.
An item of equipment marked II without an A, B or C can be used:
- A.
The equipment is unsuitable for any area
- B.
The equipment can only be used in IIA areas
- C.
The equipment can be used in all gas group areas
- D.
The equipment can only be used in IIB area
Correct Answer
C. The equipment can be used in all gas group areasExplanation
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.Rate this question:
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- 23.
Cable glands installed into Ex e boxes after 2007 are required to be:
- A.
Certified Ex d gland
- B.
Certified Ex n gland
- C.
Certified Barrier gland
- D.
Certified to IEC 60079
Correct Answer
D. Certified to IEC 60079Explanation
Cable glands installed into Ex e boxes after 2006 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. It indicates that the cable glands have been tested and approved for their safety and effectiveness in preventing the entry of flammable substances and the occurrence of sparks or ignition sources. This certification is necessary to ensure the overall safety of the installation and to comply with regulations regarding hazardous areas.Rate this question:
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- 24.
What are the requirements of threaded entry into an Ex d enclosure:
- A.
Three fully engaged threads
- B.
Five fully engaged threads
- C.
Eight fully engaged threads
- D.
Ten fully engaged threads
Correct Answer
B. Five fully engaged threadsExplanation
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.Rate this question:
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- 25.
What would be required to terminate SWA cable into an Ex e steel enclosure with 10mm threaded entry:
- A.
Fit gland, earth tag, star washer and lock nut
- B.
Fit gland, IP washer and lock nut
- C.
Fit gland
- D.
Fit gland, IP washer and star washer
Correct Answer
A. Fit gland, earth tag, star washer and lock nutExplanation
To terminate a Steel Wire Armoured (SWA) cable into an Ex e (increased safety) steel enclosure with a 10mm threaded entry, it is essential to use a comprehensive set of components to ensure a safe and compliant installation. The correct approach includes:
Fit gland: A cable gland that is compatible with SWA cables and designed for use in hazardous areas (Ex e certified) to maintain the integrity of the enclosure.
Earth tag: This provides an essential earthing connection for the metallic parts of the SWA cable, which is crucial for safety in electrical installations, especially in hazardous areas.
Star washer: Ensures good electrical contact by penetrating the surface coatings (paint, oxidation) on the enclosure, which enhances the effectiveness of the earthing connection.
Lock nut: Secures the gland in place within the threaded entry of the enclosure, ensuring that the gland and the accompanying components are mechanically stable and the ingress protection rating is maintained.Rate this question:
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- 26.
What type of gland would be installed in an enclosure marked Ex d [ia]
- A.
A flameproof gland suitable for both cable and enclosure
- B.
An increased safety gland suitable for the cable
- C.
A gland certified as Ex i and suitable for the cable
- D.
A standard industrial IP 54 gland suitable for the cable
Correct Answer
A. A flameproof gland suitable for both cable and enclosureExplanation
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.Rate this question:
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- 27.
ATEX certified equipment will have the following mark:
- A.
A crown inscribed with FLP
- B.
A hexagon inscribed IEC
- C.
A hexagon inscribed Ex
- D.
The CE marking
Correct Answer
C. A hexagon inscribed ExExplanation
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.Rate this question:
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- 28.
In electrical installations, what is the purpose of a residual current device (RCD)?
- A.
To regulate the flow of voltage in a circuit
- B.
To protect against overload conditions
- C.
To detect and interrupt abnormal electrical currents
- D.
To control the frequency of alternating current fluctuations
Correct Answer
C. To detect and interrupt abnormal electrical currentsExplanation
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.Rate this question:
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- 29.
Equipment is marked Ex d [ib]. Does this indicate:
- A.
The equipment is intrinsically safe
- B.
That the equipment can be used on IS circuits only
- C.
That the equipment is part of an intrinsically safe system
- D.
That the enclosure contains associated IS equipment
Correct Answer
D. That the enclosure contains associated IS equipmentExplanation
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.Rate this question:
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- 30.
Equipment marked IECExBAS06.0014X. What does the X indicate:
- A.
The equipment must be installed in a safe area
- B.
The equipment cannot be used outdoors
- C.
The equipment does not have an IP rating
- D.
Special conditions apply, refer to documentation
Correct Answer
D. Special conditions apply, refer to documentationExplanation
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.Rate this question:
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- 31.
Ex d equipment is called flameproof because:
- A.
It contains flammable materials
- B.
If the equipment is on fire it will continue to function
- C.
It will contain an internal explosion
- D.
It's too heavy to be used
Correct Answer
C. It will contain an internal explosionExplanation
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.Rate this question:
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- 32.
Pressure piling can result when:
- A.
Heavy equipment is mounted on piles
- B.
An ignition in one part of an enclosure causes higher explosion pressure in another part
- C.
There is a build up of pressure causing material fatigue
- D.
The gas pressure causes a vent to open
Correct Answer
B. An ignition in one part of an enclosure causes higher explosion pressure in another partExplanation
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.Rate this question:
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- 33.
Ex e equipment signifies:
- A.
Flameproof
- B.
Increased safety
- C.
Purged
- D.
Intrinsically safe
Correct Answer
B. Increased safetyExplanation
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.Rate this question:
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- 34.
A motor has marked on the certification page 'TE'. What does this indicate:
- A.
The maximum run time
- B.
The maximum disconnection time for stalled motor
- C.
The maximum temperature the motor will operate
- D.
The duty cycle of the motor
Correct Answer
B. The maximum disconnection time for stalled motorExplanation
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.Rate this question:
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- 35.
What is the minimum IP rating of Ex n equipment
- A.
IP 20
- B.
IP 44
- C.
IP 54
- D.
IP 65
Correct Answer
C. IP 54Explanation
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.Rate this question:
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- 36.
In enclosures marked with which certification can uncertified power supplies for Ex ia equipment be installed?
- A.
Ex n
- B.
Ex e
- C.
Ex i
- D.
Ex p
Correct Answer
B. Ex eExplanation
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.Rate this question:
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- 37.
What apparatus can be connected to a Zenner barrier:
- A.
Any apparatus
- B.
Simple apparatus marked Ex i
- C.
Only that specified in documentation
- D.
Only uncertified apparatus
Correct Answer
C. Only that specified in documentationExplanation
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.Rate this question:
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- 38.
The purpose of Barriers is to:
- A.
Limit the maximum energy flow to apparatus
- B.
Allow any apparatus to be installed
- C.
Allow apparatus only marked Ex i to be installed
- D.
Limit the maximum temperature of the apparatus
Correct Answer
A. Limit the maximum energy flow to apparatusExplanation
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.Rate this question:
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- 39.
Non IS and IS equipment is installed in the same enclosure. What is the minimum gap between terminals of each type:
- A.
3mm
- B.
6mm
- C.
30mm
- D.
50mm
Correct Answer
D. 50mmExplanation
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.Rate this question:
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- 40.
For workers in potentially explosive environments it is essential to understand:
- A.
The basic requirements of working in hazardous areas
- B.
The manufacturers literature
- C.
The manufacturing standards
- D.
Panel wiring diagrams
Correct Answer
A. The basic requirements of working in hazardous areasExplanation
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.Rate this question:
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- 41.
Isolation requires that the neutral conductor:
- A.
Remains connected
- B.
Is easily disconnected
- C.
Is fused
- D.
Is of the colour blue
Correct Answer
A. Remains connectedExplanation
In isolation, the neutral conductor must remain connected to ensure the continuity of the electrical circuit. This ensures that the electrical system remains balanced and that current flows properly throughout the circuit, preventing potential hazards such as voltage imbalances or electrical faults.Rate this question:
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- 42.
The minimum gap between Ex d flanged joints and other obstructions in a IIC environment is:
- A.
10mm
- B.
20mm
- C.
30mm
- D.
40mm
Correct Answer
D. 40mmExplanation
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.Rate this question:
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- 43.
The fixings of Ex d equipment should:
- A.
All be spanner tight
- B.
Be tightened using a torque wrench set at 50Nm
- C.
Have only alternate bolts tightened
- D.
Be missing
Correct Answer
A. All be spanner tightExplanation
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.Rate this question:
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- 44.
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:
- A.
Put at least one bolt back and hang a danger notice
- B.
Put at least half the bolts back and hang a danger notice
- C.
Put all bolts back spanner tight and check the flange gaps
- D.
Put no bolts back and leave it until the next inspection
Correct Answer
C. Put all bolts back spanner tight and check the flange gapsExplanation
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.Rate this question:
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- 45.
A flameproof motor installed in 2005 has an Ex e terminal box. What is the gland selection:
- A.
Ex d gland
- B.
Uncertified IP 68 gland
- C.
Ex i gland
- D.
E1W gland
Correct Answer
D. E1W glandExplanation
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.Rate this question:
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- 46.
What should the maximum earth impedance be for a Zenner barrier:
- A.
1MΩ
- B.
100Ω
- C.
10Ω
- D.
1Ω
Correct Answer
D. 1ΩExplanation
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.Rate this question:
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- 47.
What is the minimum CSA when using a single earthing conductor for a Zener barrier:
- A.
1.5mm2
- B.
2.5mm2
- C.
4.0mm2
- D.
6.0mm2
Correct Answer
C. 4.0mm2Explanation
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.Rate this question:
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- 48.
IS and non-IS cables are to be installed on site. What are the requirements:
- A.
All cables are to be run on separate cable tray
- B.
All cables can be run with any other cables
- C.
The IS or non-IS cables needs to be armoured, metal sheathed or screened
- D.
Both the IS and non-IS needs to be armoured, metal sheathed and screened
Correct Answer
C. The IS or non-IS cables needs to be armoured, metal sheathed or screenedExplanation
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.Rate this question:
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- 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:
- A.
Any spare core
- B.
A spare core from a pair where the other is used on another circuit
- C.
A 3 core cable must be run
- D.
Use one core from a spare pair and treat the other core as an unused core
Correct Answer
D. Use one core from a spare pair and treat the other core as an unused coreExplanation
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.Rate this question:
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- 50.
An Ex d IIC enclosure is to be terminated using SWA cable. What is the minimum requirement of the gland:
- A.
E1W plastic gland
- B.
Exd IIC gland
- C.
Exe IIC gland
- D.
Ex d IIC Barrier gland
Correct Answer
D. Ex d IIC Barrier glandExplanation
When terminating an Ex d IIC enclosure using SWA (Steel Wire Armoured) cable, the minimum requirement is to use a barrier gland. The barrier gland is sealed with a setting compound and complies with IEC 60079-1. This type of gland is designed to maintain the flameproof integrity of the enclosure.Rate this question:
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Current Version
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Apr 19, 2024Quiz Edited by
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Jun 18, 2019Quiz Created by
R.scaplehorn
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