Question 1

Conduit/cable system seals minimize the passage of ____ and prevent the passage of flames from one portion of the electrical installation to another through the conduit.

Accepted Answer

Conduit/cable system seals are used to prevent the passage of gas/vapors and to minimize the passage of sparks. They do not play a role in preventing the flow of electricity or water.

Question 2

Group G is the catchall group whose atmospheres contain combustible dusts not included in Group E or F, including ____.

Accepted Answer

Group G includes combustible dusts such as those from flour, grain, wood, plastic, and chemicals, which are not included in Group E or F.

Question 3

Equipment markings shall include: (1) class, (2) division, (3) material classification group, (4) equipment temperature, and (5) ____.

Accepted Answer

The other options (A, B, and C) are not typically included in equipment markings for hazardous locations. The ambient temperature range is important to note for ensuring safe operation of the equipment in the specified environment.

Question 4

Type PVC conduit and Type RTRC conduit can be used when first surrounded by at least ____ of concrete, followed by a minimum cover of 24 in. (top of conduit to grade).

Accepted Answer

Type PVC conduit and Type RTRC conduit must be surrounded by at least 2 inches of concrete before being covered by a minimum of 24 inches of earth.

Question 5

Article 515 covers a property or portion of a property where ____ are received by tank vessel, pipelines, tank car, or tank vehicle and are stored or blended in bulk for the purpose of distribution.

Accepted Answer

Article 515 covers properties where flammable liquids are received by tank vessel, pipelines, tank car, or tank vehicle and are stored or blended in bulk for the purpose of distribution.

Question 6

The simultaneous presence of flammable gases, flammable liquid-produced vapors, combustible liquid-produced vapors, or combustible dusts shall be considered when determining the ____ of the electrical equipment.

Accepted Answer

The simultaneous presence of flammable gases, vapors, or combustible dusts is a critical factor in determining the safe operating temperature of electrical equipment to prevent ignition.

Question 7

Flammable/combustible gases (or liquid-produced vapor) are categorized by considering ____ and minimum igniting current ratio (MIC ratio) values.

Accepted Answer

Flammable/combustible gases (or liquid-produced vapor) are categorized by considering maximum experimental safe gap (MESG) values. This value corresponds to the largest gap size that will prevent ignition of a flammable mixture on one side of a barrier when an ignition source is applied on the other side of the barrier. The minimum igniting current ratio (MIC ratio) is a separate parameter used to assess the combustibility of a gas or vapor.

Question 8

The temperature marking for organic dusts that may dehydrate or carbonize, the temperature marking shall not exceed the lower of either the ignition temperature or ____.

Accepted Answer

The temperature marking for organic dusts that may dehydrate or carbonize should not exceed the lower of either the ignition temperature or 165°C. Therefore, the correct choice is B.

Question 9

Sealing compound shall ____.

Accepted Answer

Sealing compound needs to be able to withstand surrounding atmosphere or liquids in order to effectively provide a seal. The other options are not necessarily requirements for sealing compound.

Question 10

The space adjacent to an enclosed dipping (or coating) process/apparatus is ____.

Accepted Answer

The answer of The space adjacent to an enclosed dipping...

Question 11

Equipment protection techniques may include explosionproof junction boxes, dusttight enclosures, heremetic sealing and ____.

Accepted Answer

Nonincendive wiring is a common equipment protection technique used in hazardous environments. It limits electrical energy to a level that is not capable of igniting explosive gases or combustible dusts. Explosionproof junction boxes, dusttight enclosures, and hermetic sealing are also effective methods of equipment protection but are not the best choice for this scenario. Polycoating materials and non-flammable paint are not equipment protection techniques.

Question 12

Areas in a garage adjacent to classified locations in which flammable vapor release is unlikely (such as a storeroom) shall be unclassified where ____.

Accepted Answer

The area should be mechanically ventilated at a rate of four (or more) air changes per hour. This is because it reduces the concentration of flammable vapors and makes it less likely for an explosion to occur. The other options, negative air flow and hermetical sealing around doors, are not sufficient on their own to prevent flammable vapor release. The option about electrical wiring passing within 10 feet of the pit area is irrelevant to the classification of the adjacent area.

Question 13

Garages used for parking or storage are ____.

Accepted Answer

Garages used for parking or storage can be permitted to be unclassified depending on the specific codes and regulations governing the area and the type of vehicles stored. This classification allows for flexibility in the use and design of the space.

Question 14

Additional seals apply to the ____ of the Class I locations.

Accepted Answer

The answer of Additional seals apply to the ____ of...

Question 15

Hazardous (classified) locations divide atmospheric identifications for Class I, Divisions 1 and 2, locations into ____.

Accepted Answer

Hazardous locations for Class I, Divisions 1 and 2 are divided into Groups A, B, C, and D.

Question 16

All cut ends of intermediate metal conduit (IMC) and rigid metal conduit (RMC) shall be ____.

Accepted Answer

All cut ends of intermediate metal conduit (IMC) and rigid metal conduit (RMC) shall be reamed or otherwise finished to remove rough edges. This is to ensure that the conduit does not damage the insulation on wires as they are pulled through the conduit, and to prevent injury to anyone working with the conduit. The other answer choices are not necessary or applicable for this situation.

Question 17

Tensile stress at Type MI cable termination fittings can be avoided by ____.

Accepted Answer

Tensile stress occurs when there is a stretching force on the cable termination fitting. Proper installation and support methods can prevent this from happening. Choosing the appropriate cable diameter, proper grounding techniques, and correct insulation methods may also be important factors, but they do not directly address the issue of tensile stress.

Question 18

Hazardous (classified) locations are divided into certain categories and subcategories, otherwise known as ____.

Accepted Answer

Hazardous (classified) locations are classified into different classes and divisions according to their potential risk to ignite or explode. This classification system is defined by the National Electrical Code (NEC) and includes different subcategories within each class and division.

Question 19

Class II locations are hazardous because of the presence of ____.

Accepted Answer

Class II locations are hazardous because of the presence of combustible dust. Class II locations are areas where combustible dust in the air may be present in sufficient quantities to produce explosive or ignitable mixtures. Examples of Class II locations include grain elevators, coal preparation plants, and sugar refineries.

Question 20

____ locations contain ignitable or combustible elements (gases, dust, fibers, etc.) in quantities sufficient to produce explosive (or ignitable) mixtures.

Accepted Answer

Division 1 locations are considered hazardous locations where ignitable or combustible elements are present in quantities sufficient to produce explosive (or ignitable) mixtures under normal operating conditions.

Quiz 15: Hazardous Classified Locations