Lesson 6: Article 505 - Zone 0, 1, And 2 Locations Flashcards by Jordan Knutson

A type of protection used in Zone 1 and 2 locations, where the enclosure will withstand an internal explosion of a flammable mixture that has penetrated into the interior, without suffering damage and without causing ignition, through any joints or structural openings in the enclosure of an external explosive gas atmosphere consisting of one or more of the gases or vapors for which it is designed is ______.

a. explosionproof
b. flameproof “d”
c. increased safety “e”
d. type of protection “n”

NEC REF:

b. flameproof “d”

100

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A protection method where electrical parts that could ignite an explosive atmosphere by either sparking or heating are enclosed in a compound in such a way that this explosive atmosphere cannot be ignited is type of protection ______.

a. encapsulation “d”
b. encapsulation “f”
c. encapsulation “m”
d. encapsulation “q”

NEC REF:

c. encapsulation “m”

100

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A protection method applied to electrical equipment that does not produce arcs or sparks in normal service and under specified abnormal conditions, in which additional measures are applied so as to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks is type of protection ______.

a. flameproof “d”
b. increased safety “e”
c. intrinsic safety “I”
d. none of the above

NEC REF:

b. increased safety “e”

100

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Associated apparatus consists of circuits that are not necessarily intrinsically safe themselves but that affect the energy in intrinsically safe circuits and are relied on to maintain intrinsic safety. What two options are provided for the apparatus?

I. Electrical apparatus that has an alternative type of protection for use in the appropriate Hazardous (Classified) Location.
II. Electrical apparatus that does not have a type of protection for use in the appropriate Hazardous (Classified) Location.
III. Electrical apparatus not so protected that shall not be used within a Hazardous (Classified) Location.
IV. Electrical apparatus not so protected that shall only be used within a Hazardous (Classified) Location.

a. I. or III.
b. I. or IV.
c. II. or IV.
d. III. or IV.

NEC REF:

a. I. or III.

100

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Optical System with Interlock “op sh” minimizes the risk of ignition in explosive atmospheres from optical radiation where visible or infrared radiation is confined inside optical fiber or other transmission medium with interlock cut-off provided to reliably reduce the unconfined beam strength to safe levels within a specified time in case the confinement fails and the radiation becomes unconfined.

a. True
b. False

NEC REF:

True

100

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Refrigerant machinery rooms containing ammonia refrigeration systems, which are equipped with adequate mechanical ventilation that operate continuously or are initiated by a detection system at a concentration not exceeding ______, shall be permitted to be classified as “unclassified” locations.

a. 120 ppm
b. 130 ppm
c. 140 ppm
d. 150 ppm

NEC REF:

d. 150 ppm

505.5(A)(2)

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A Zone 0 location is a location in which ignitible concentrations of flammable gases or vapors are present continuously, or ignitible concentrations of flammable gases or vapors are present for long periods of time.

a. True
b. False

NEC REF:

a. True

505.5(B)(1)

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An area in which equipment is operated or processes are carried on, of such a nature that equipment breakdown or faulty operations could result in the release of ignitible concentrations of flammable gases or vapors and also cause simultaneous failure of electrical equipment in a mode to cause the electrical equipment to become a source of ignition would be classified as ______.

a. Zone 0
b. Zone 1
c. Zone 2
d. None of the above

NEC REF:

b. Zone 1

505.5(B)(2)(3)

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A location in which ignitible concentrations of flammable gases or vapors normally are prevented by positive mechanical ventilation but which may become hazardous as a result of failure or abnormal operation of the ventilation equipment would be classified as ______.

a. Zone 0
b. Zone 1
c. Zone 2
d. None of the above

NEC REF:

c. Zone 2

505.5(B)(3)(3)

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When using the zone classification system, ______ is intended for use in describing atmospheres that contain firedamp: a mixture of gases, composed mostly of methane, found underground, usually in mines which are not covered by the NEC.

a. Group I
b. Group II
c. Group III
d. Group IV

a. Group I

Note: See NEC 505.6 Informational Note No. 1.

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Materials Group IIA is defined as atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value ______ 0.90 mm or minimum igniting current (MIC) ratio greater than 0.80.

a. equal to
b. equal to or greater than
c. greater than
d. less than

NEC REF:

c. greater than

505.6(C)

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Zone ______ is equivalent to a combination of Class I, Group A and Class I, Group B.

a. Group IIA
b. Group IIB
c. Group IIC
d. Group IID

c. Group IIC

Note: See NEC 505.6(A) Informational Note.

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An area in which ignitible concentrations of flammable gases or vapors normally are prevented by negative mechanical ventilation but which may become hazardous as a result of failure or abnormal operation of the ventilation equipment would be classified as Zone 2.

a. True
b. False

NEC REF:

False

505.5(B)(3)(3)

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Using the Zone system, atmospheres containing acetylene, hydrogen, or flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value less than or equal to 0.50 millimeters or minimum igniting current ratio (MIC ratio) less than or equal to 0.45 millimeters are included in ______.

a. Group IIA
b. Group IIB
c. Group IIC
d. Group IID

NEC REF:

c. Group IIC

505.6(A)

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Flameproof equipment with flanged joints, installed in Class I, Group IIC locations, shall have a minimum distance of ______ to any solid obstacle that is not a part of the equipment (such as steelworks, walls, weather guards, mounting brackets, pipes, or other electrical equipment) unless the equipment is listed for a smaller distance of separation.

a. 10 mm
b. 20 mm
c. 30 mm
d. 40 mm

NEC REF:

d. 40 mm

Table 505.7(D)

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One of the requirements for using a gas detection system as a protection technique in industrial establishments is that the gas detection equipment must be ______ for Zone 1 and detection of the specific gas or vapor that will be encountered.

a. approved
b. labeled
c. listed
d. suitable

NEC REF:

c. listed

505.8(I)(1)(a)

One of the conditions for allowing an enclosed space without a source of flammable gases or vapors, but with an opening into a Zone 2 location with a flammable gas detection system to utilize wiring practices suitable for unclassified installations is to provide an alarm that will sound at not more than ______ of the lower flammable limit.

a. 10%
b. 20%
c. 30%
d. 40%

NEC REF:

b. 20%

505.8(I)(3)(1)

Which of these protection techniques can be used for apparatus and associated apparatus in Zone 0, Zone 1, or Zone 2 locations for which they are listed?

a. Increased safety “e”
b. Intrinsic safety “i”
c. Oil immersion “o”
d. Protection “n”

NEC REF:

b. Intrinsic safety “i”

505.8(C)

A type of protection applied to electrical equipment that does not produce arcs or sparks in normal service and under specified abnormal conditions, in which additional measures are applied to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks, is the ______ protection technique.

a. encapsulation “m”
b. increased safety “e”
c. intrinsic safety “i”
d. special protection “s”

NEC REF:

b. increased safety “e”

100

The pressurized enclosure “p” protection technique uses the technique of guarding against the ingress of a possibly explosive external atmosphere into an enclosure by maintaining a protective gas inside the enclosure at a pressure above the pressure of the atmosphere outside the enclosure.

a. True
b. False

NEC REF:

True

100

The temperature marking shall not exceed the ______ of the specific gas or vapor to be encountered.

a. autoignition temperature
b. lower flammable limit
c. temperature class
d. upper flammable limit

NEC REF:

a. autoignition temperature

505.9(D)

Conduit and fittings, installed in Zone 0, Zone 1, and Zone 2, shall be made wrenchtight to prevent ______ when fault current flows through the conduit system, and to ensure the explosionproof or flameproof integrity of the conduit system where applicable.

a. arcing
b. overheating
c. sparking
d. b. and c.

NEC REF:

c. sparking

505.9(E)

An optical fiber cable, installed in a Zone 0, Zone 1, or Zone 2 location, with or without current-carrying current (______ optical fiber cable), shall be installed to address the associated fire hazard and sealed to address the associated explosion hazard in accordance with the requirements of Sections 505.15 and 505.16.

a. duplex
b. hybrid
c. multimode
d. simplex

NEC REF:

b. hybrid

505.9(F)

Suitability of equipment identified for Zone 0, Zone 1, and Zone 2 shall be determined by ______.

I. equipment listing or labeling
II. evidence acceptable to the authority having jurisdiction, such as a manufacturer’s self-evaluation or an owner’s engineering judgment
III. evidence of equipment evaluation from a qualified testing laboratory or inspection agency concerned with product evaluation

a. I.
b. I., II., and III.
c. I. and III.
d. II. and III.

NEC REF:

b. I., II., and III.

505.9(A)

Equipment identified for Class I, Division 1 or Class I, Division 2 shall, in addition to being marked in accordance with 500.8(C), be permitted to be marked with ______. I. applicable gas classification group(s) in accordance with Table 505.9(C)(1) II. Class I, Zone 1 or Zone 1; Class I, Zone 2 or Zone 2 (as applicable) III. temperature classification in accordance with 505.9(D) a. I. and II. b. I., II., and III. c. I. and III. d. II. and III. NEC REF:

b. I., II., and III. 505.9(C)(1)

Match the label statement to the marking that best describes an example of an entry required by 505.9(C)(2). - Area classification - Equipment protection level (EPL) - Material group - Symbol for equipment built to American standards - Temperature classification - Type(s) of protection designation Choices: - AEx - Class 1 Zone 0 - T6 - Ga - IIC - ia

- Area classification. - Class 1 Zone 0 - Equipment protection level (EPL) - Ga - Material group. - IIC - Symbol for equipment built to American standards. - AEx - Temperature classification. - T6 - Type(s) of protection designation. - ia

Electrical equipment for use in Zone 0, Zone 1, and Zone 2 locations that is designed for use in a range of ambient temperatures other than ______ is considered to be special; and the ambient temperature range shall then be marked on the equipment, including either the symbol “Ta” or “Tamb” together with the special range of ambient temperatures, in degrees Celsius. a. –20°C to –40°C b. –20°C to +40°C c. +20°C to +40°C d. none of the above NEC REF:

b. –20°C to +40°C 505.9(D)

Type PVC conduit and Type RTRC conduit shall be permitted in Zone 1 locations, where encased in a concrete envelope a minimum of 2 in. thick and provided with not less than ______ of cover measured from the top of the conduit to grade. a. 12" b. 18" c. 24" d. 30" NEC REF:

c. 24" 505.15(B)(1)(6)

Separate intrinsic safety type of protection “ic” systems, installed in Zone 2 locations, shall be installed in which of the following? I. In multiconductor cables where the conductors of each circuit are within a grounded metal shield II. In multiconductor cables where the conductors of each circuit have a minimum insulation thickness of 0.25 inches III. In separate cables a. I. and II. b. I., II., and III. c. I. and III. d. II. and III. NEC REF:

c. I. and III. 505.15(C)(1)(7)

In Zone 0 locations, seals shall be provided within ______ of where a conduit leaves a Zone 0 location. a. 18" b. 3' c. 6' d. 10' NEC REF:

d. 10' 505.16(A)(1)

Conduit seals in Zone 1 locations shall be provided within ______ for each conduit entering enclosures having type of protection “d,” “db,” “e,” or “eb.” a. 2" b. 12" c. 18" d. 24" NEC REF:

a. 2" 505.16(B)(1)

The sealing compound used in Zone 0, Zone 1, and Zone 2 locations shall provide a seal against passage of gas or vapors through the seal fitting, shall not be affected by the surrounding atmosphere or liquids, and shall not have a melting point less than ______. a. 180°F b. 200°F c. 210°F d. 220°F NEC REF:

b. 200°F 505.16(D)(2)

The cross-sectional area of the conductors or optical fiber tubes (metallic or nonmetallic) permitted in a seal in a Zone 0, Zone 1, or Zone 2 location shall not exceed ______ of the cross-sectional area of a rigid metal conduit of the same trade size unless it is specifically listed for a higher percentage of fill. a. 20% b. 25% c. 30% d. 40% NEC REF:

b. 25% 505.16(D)(5)

The extension of the flexible cord within a ______ raceway between the wet-pit and the power source for an electric submersible pump shall be permitted. a. metallic b. nonmetallic c. suitable d. none of the above NEC REF:

c. suitable 505.17(A)

A power-supply cord used for a Zone 2 instrumentation connection cannot exceed three feet, and it must be of a type listed for extra-hard usage or for hard usage if protected by location. a. True b. False NEC REF:

True 505.17(B)(3)

There shall be no uninsulated exposed parts, such as electrical conductors, buses, terminals, or components in Zone 0, 1, or 2 locations that operate at more than _____ ( ______ in wet locations). a. 24 V / 12 V b. 40 V / 20 V c. 60 V / 30 V d. none of the above NEC REF:

d. none of the above 505.19

A drain or vent located between a single process seal and a conduit or cable seal, sufficiently sized to prevent over pressuring the conduit or cable seal above ______, is one of the additional means permitted to be used to mitigate a single process seal failure. a. 1,400 Pa b. 1,453 Pa c. 1,487 Pa d. 1,493 Pa NEC REF:

d. 1,493 Pa 505.26(3)