Question 1

What conditions are required for flexible cords and attachment plugs to be used in hazardous areas?

Accepted Answer

When they are used, they must comply wit...

Question 2

A Group A atmosphere contains ____.

Accepted Answer

A)   hydrogen
B)   2-butanol
C)   butadiene
D)   acetylene

Question 3

Some types of explosionproof enclosures are designed to be drilled and tapped in the field. When this is done, at least ____ full threads should be engaged between the conduit and the enclosure.

Accepted Answer

A)   three
B)   five
C)   seven
D)   11

Question 4

____ locations are considered to be the most hazardous.

Accepted Answer

A)   Class I, Division 1
B)   Class I, Division 2
C)   Class II, Division 1
D)   Class II, Division 2

Question 5

The ____ rating indicates the maximum operating temperature of a luminaire.

Accepted Answer

A)   T
B)   MOT
C)   MT
D)   TEMP

Question 6

If it is necessary to remove a substance from the surface of an explosionproof enclosure that cannot be cleaned with solvent, use ____.

Accepted Answer

A)   a chisel
B)   a putty knife
C)   sandpaper
D)   a fine steel wool

Question 7

What is the hazard level of an aircraft hangar?

Accepted Answer

NEC 513.1 defines an aircraft hangar as ...

Question 8

Describe the mating surfaces of explosionproof equipment.

Accepted Answer

Great care must be exercised when instal...

Question 9

As a general rule, equipment installed in a Class II location must be ____.

Accepted Answer

A)   dustproof
B)   explosionproof
C)   waterproof
D)   dust-ignitionproof D

Question 10

A Group E atmosphere contains ____.

Accepted Answer

A)   combustible metal dusts
B)   carbonaceous dusts
C)   acetaldehyde
D)   propylene oxide A

Question 11

____ are used to minimize the passage of gas and to prevent the passage of flame through the conduit.

Accepted Answer

A)   Outlet boxes
B)   Seals
C)   Fibers
D)   Vacuums B

Question 12

What is the difference between Division 1 and Division 2 hazardous locations?

Accepted Answer

Hazardous locations are divided into two...

Question 13

When circuit breakers are installed in Class I locations, they must be ____.

Accepted Answer

A)   dustproof
B)   dust-ignitionproof
C)   explosionproof
D)   waterproof

Question 14

Intrinsically safe equipment and circuits operate ____.

Accepted Answer

A)   without electricity
B)   at low power levels
C)   at high voltage
D)   at high current

Question 15

When horizontal seals are installed, ____ fiber dams must be used.

Accepted Answer

A)   two
B)   three
C)   four
D)   five

Question 16

In general, the floor area of a garage, up to a level of 18 in. (450 mm)  above the floor, is considered to be a ____ location.

Accepted Answer

A)   Class I, Division 1
B)   Class I, Division 2
C)   Class II, Division 1
D)   Class II, Division 2

Question 17

Class III locations are areas that contain combustible ____.

Accepted Answer

A)   dusts
B)   gases
C)   fibers
D)   vapors

Question 18

If a stem is longer than ____ in., lateral braces must be placed within 12 in. (300 mm)  of the luminaire, or an explosionproof flexible coupling must be used within 12 in. (300 mm)  of the junction box.

Accepted Answer

A)   6
B)   10
C)   12
D)   14

Question 19

What do Group C and D atmospheres encompass?

Accepted Answer

Group C contains flammable gas or flamma...

Question 20

To help prevent condensation, some vertical seals are designed with ____.

Accepted Answer

A)   fiber dams
B)   conductors
C)   drain plugs
D)   horizontal seals

Exam 19: Hazardous Locations

What conditions are required for flexible cords and attachment plugs to be used in hazardous areas?

Correct AnswerverifiedWhen they are used, they must comply wit...View AnswerShow Answer

A Group A atmosphere contains ____.

Correct AnswerverifiedShow Answer

Some types of explosionproof enclosures are designed to be drilled and tapped in the field. When this is done, at least ____ full threads should be engaged between the conduit and the enclosure.

Correct AnswerverifiedShow Answer

____ locations are considered to be the most hazardous.

Correct AnswerverifiedShow Answer

The ____ rating indicates the maximum operating temperature of a luminaire.

Correct AnswerverifiedShow Answer

If it is necessary to remove a substance from the surface of an explosionproof enclosure that cannot be cleaned with solvent, use ____.

Correct AnswerverifiedShow Answer

What is the hazard level of an aircraft hangar?

Correct AnswerverifiedNEC 513.1 defines an aircraft hangar as ...View AnswerShow Answer

Describe the mating surfaces of explosionproof equipment.

Correct AnswerverifiedGreat care must be exercised when instal...View AnswerShow Answer

As a general rule, equipment installed in a Class II location must be ____.

Correct AnswerverifiedD

A Group E atmosphere contains ____.

Correct AnswerverifiedA

____ are used to minimize the passage of gas and to prevent the passage of flame through the conduit.

Correct AnswerverifiedB

What is the difference between Division 1 and Division 2 hazardous locations?

Correct AnswerverifiedHazardous locations are divided into two...View AnswerShow Answer

When circuit breakers are installed in Class I locations, they must be ____.

Correct AnswerverifiedShow Answer

Intrinsically safe equipment and circuits operate ____.

Correct AnswerverifiedShow Answer

When horizontal seals are installed, ____ fiber dams must be used.

Correct AnswerverifiedShow Answer

In general, the floor area of a garage, up to a level of 18 in. (450 mm) above the floor, is considered to be a ____ location.

Correct AnswerverifiedShow Answer

Class III locations are areas that contain combustible ____.

Correct AnswerverifiedShow Answer

If a stem is longer than ____ in., lateral braces must be placed within 12 in. (300 mm) of the luminaire, or an explosionproof flexible coupling must be used within 12 in. (300 mm) of the junction box.

Correct AnswerverifiedShow Answer

What do Group C and D atmospheres encompass?

Correct AnswerverifiedGroup C contains flammable gas or flamma...View AnswerShow Answer

To help prevent condensation, some vertical seals are designed with ____.

Correct AnswerverifiedShow Answer

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When they are used, they must comply wit...
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NEC 513.1 defines an aircraft hangar as ...
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Great care must be exercised when instal...
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D

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A

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B

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Hazardous locations are divided into two...
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Group C contains flammable gas or flamma...
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Correct Answer
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