Deck 15: Hazardous Classified Locations

Question 1

When mixed with air, a flammable/combustible gas (or liquid-produced vapor) has a _____ of no more than 0.45 mm.

A) maximum ignition yield (MIY)
B) minimum explosive trigger (MET)
C) maximum experimental safe gap (MESG)
D) minimum ignition pressure gap (MIPG)

Answer 1

C

Question 2

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

A) Division 1
B) Category 1
C) Division 2
D) Category 2

Answer 2

A

Question 3

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

A) sites and subsites
B) sites and locations
C) classes and divisions
D) codes and divisions

Answer 3

C

Question 4

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

A) jacketed with aluminum or composite materials
B) reamed or otherwise finished to remove rough edges
C) grounded to a stable fixture
D) jacketed with plastic or polymer

Question 5

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

A) 100°C (212°F)
B) 165°C (329°F)
C) 175°C (347°F)
D) 200°C (392°F)

Question 6

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

A) combustible vapors
B) potential arcing
C) volatile mixtures
D) combustible dust

Question 7

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

A) designed with negative air flow
B) mechanically ventilated at a rate of four (or more) air changes per hour
C) designed with hermetical sealing around all doors
D) no electrical wiring passes within 10 feet of the pit area

Question 8

Unless otherwise specified in 500.8(C)(6), equipment markings shall include: (1) class, (2) division, (3) material classification group, (4) equipment temperature, and (5) ____.

A) maximum voltage
B) material composition
C) average draw
D) ambient temperature range

Question 9

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

A) polycoating
B) nonflammable paint
C) nonincendive
D) damping

Question 10

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

A) Groups 1A and 2A
B) Categories A and B
C) Categories A, B, C, and D
D) Groups A, B, C, and D

Question 11

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.

A) chemicals
B) natural gases
C) flammable liquids
D) flammable vapors

Question 12

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

A) anterior and posterior sections
B) distal and medial boundaries
C) conduit entrances
D) horizontal as well as vertical boundaries

Question 13

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.

A) sparks
B) water
C) electrical flow
D) gas/vapors

Question 14

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

A) proper installation and support methods
B) choosing the appropriate cable diameter
C) proper grounding techniques
D) correct insulation methods

Question 15

Type PVC conduit, Type RTRC conduit, and Type HDPE conduit can be used when first surrounded by at least ____ of concrete, followed by a minimum cover of 24 in.(600 mm) (top of conduit to grade).

A) 2 in.(50 mm)
B) 4 in.(100 mm)
C) 8 in.(200 mm)
D) 12 in.(300 mm)

Question 16

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

A) flour, grain, wood, plastic, and chemicals
B) metal and polymer
C) paper and paint
D) chemicals, metal, and rubber products

Question 17

Garages used for parking or storage are ____.

A) permitted to be unclassified
B) classified as Division I
C) classified according to type of vehicle
D) classified as Division II

Question 18

Electrical wiring and electrical utilization equipment located within 5 ft (1525 mm) of a vapor source shall be suitable for _____ locations.

A) Class I
B) Class II
C) Class III
D) Class IV

Question 19

Sealing compound shall ____.

A) have a melting point of 93°F or higher
B) cement sections of conduit together
C) not be affected by surrounding atmosphere or liquids
D) provide a seal against the passage of sparks

Question 20

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.

A) grounding arrangement
B) safe operating temperature
C) shielding
D) sparking potential

Question 21

Askarel-containing transformers rated in excess of 25 kVA shall have ____.

A) negative airflow to all adjacent areas within a scope of 10 ft
B) insulated grounding wires connecting the transformer case and an earth ground
C) at least 6 in.(150 mm) of airspace between the transformer case and any adjacent combustible material
D) a properly installed chimney

Question 22

The quantity of combustible dust that may be present and the ____ are factors that merit consideration in determining the classification and may result in an unclassified area.

A) adequacy of dust removal systems
B) potential for arcing
C) chemical composition of the dust
D) proximity of sprinkler systems

Question 23

Class III, Division 1 and 2 portable lighting equipment shall have handles and ____.

A) substantial guards
B) sealed casings
C) positive airflow
D) cross-wiring

Question 24

Class III locations are hazardous because of the presence of ____, or where materials producing combustible flyings are handled, manufactured, or used, even though they are not likely to be airborne in quantities sufficient to produce ignitable mixtures.

A) volatile gases
B) unstable vapors
C) fine dust
D) easily ignitable fibers

Question 25

Class II, Division 1 locations require interlocked armor Type MC cable having an overall jacket of suitable polymeric material and provided with termination fittings and ____.

A) LFLC with listed fittings
B) LFNC with listed fittings
C) LFLD with listed fittings
D) LFMD with listed fittings