Equipment Identification and Safety in Hazardous Locations Quiz
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Questions and Answers

According to NFPA 497, which group classification includes atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial alloys?

  • Group F
  • Group G
  • Group E (correct)
  • Group H

    • According to NFPA 497, which group classification includes atmospheres containing combustible carbonaceous dusts that have more than 8 percent total entrapped volatiles?

  • Group E
  • Group F (correct)
  • Group H
  • Group G

    • According to NFPA 497, which group classification includes atmospheres containing combustible dusts not included in Group E or Group F, such as flour, grain, wood, plastic, and chemicals?

  • Group F
  • Group E
  • Group G (correct)
  • Group H

    • According to NFPA 499, which class of combustible fibers/flyings shall not be further grouped?

    <p>Class III</p> Signup and view all the answers

    Which type of motors must consider abnormal load conditions when evaluating external temperatures?

    <p>Both explosionproof and dust-ignitionproof motors</p> Signup and view all the answers

    When is awareness of increased temperatures in motors controlled by variable-speed drives important?

    <p>When they are operated at lower speeds and are dependent on the fan for cooling</p> Signup and view all the answers

    What happens when flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors and combustible dusts are or might be present at the same time?

    <p>They create a hazardous environment that requires simultaneous classifications</p> Signup and view all the answers

    Which of the following is true about Class I, Group C materials?

    <p>They have a value greater than 0.45 mm and less than or equal to 0.75 mm</p> Signup and view all the answers

    Which of the following is true about Class I, Group D materials?

    <p>They have a minimum igniting current (MIC) ratio greater than 0.80</p> Signup and view all the answers

    Which of the following is true about Class I, Group D materials?

    <p>They have a maximum experimental safe gap (MESG) value greater than 0.75 mm</p> Signup and view all the answers

    Which protection technique is permitted for equipment in Class II, Division 2 or Class III, Division 1 or 2 locations?

    <p>Dusttight</p> Signup and view all the answers

    What is the process of supplying an enclosure with a protective gas at a sufficient flow and positive pressure to reduce the initial concentration of any flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors to an acceptable level called?

    <p>Purging</p> Signup and view all the answers

    Which protection technique is permitted for equipment in Class I, Division 1 or Division 2; Class II, Division 1 or Division 2; or Class III, Division 1 or Division 2 locations?

    <p>Intrinsic Safety</p> Signup and view all the answers

    Which protection technique is permitted for current-interrupting contacts in Class I, Division 2 locations?

    <p>Oil Immersion</p> Signup and view all the answers

    According to NFPA 30, what is considered adequate ventilation?

    <p>A location with a gas concentration of not more than 40 percent of the lower flammable limit</p> Signup and view all the answers

    In a Class I, Division 2 hazardous location, what activates an alarm in a detection system for flammable gases?

    <p>Sensing a gas concentration of not more than 20 percent of the lower flammable limit</p> Signup and view all the answers

    What is the suitable power disconnecting device for a detection system for flammable gases located inside a building or enclosed space?

    <p>Suitable for Class I, Division 1</p> Signup and view all the answers

    What is the suitable power disconnecting device for a detection system for flammable gases located outside a building or enclosed space?

    <p>Suitable for the location in which it is installed</p> Signup and view all the answers

    Which protection technique is permitted for equipment in Class I or II, Division 1 or 2 locations for which the equipment is identified?

    <p>Inherently Safe Optical Radiation</p> Signup and view all the answers

    Which protection technique is permitted for equipment in Class I or II, Division 2 locations for which the equipment is identified?

    <p>Protected Optical Radiation</p> Signup and view all the answers

    Which protection technique is permitted for skin effect trace heating equipment in Class I, Division 2; Class II, Division 2; or Class III, Division 2 locations for which it is listed?

    <p>Protection by Skin Effect Trace Heating</p> Signup and view all the answers

    Which protection technique is permitted for electrical resistance trace heating equipment in Class I, Division 1; Class I, Division 2; Class II, Division 1; Class II, Division 2; Class III, Division 1; or Class III, Division 2 locations for which it is listed?

    <p>Protection by Electrical Resistance Trace Heating</p> Signup and view all the answers

    Which of the following is NOT a requirement for Class I equipment in hazardous locations?

    <p>Not exceeding the maximum surface temperatures specified in 503.5</p> Signup and view all the answers

    Which of the following is NOT a requirement for Class II equipment in hazardous locations?

    <p>Having explosionproof seals installed within 450 mm (18 in.) of the enclosure for conduit runs into explosionproof equipment</p> Signup and view all the answers

    Which of the following is NOT a requirement for Class III equipment in hazardous locations?

    <p>Not having any exposed surface that operates at a temperature higher than the temperature specified in 500.8(D)(2)</p> Signup and view all the answers

    Which of the following is a requirement for equipment installed in a Class I, Division 1 location?

    <p>Incorporating seals in accordance with 501.15(A) or (D)</p> Signup and view all the answers

    Which of the following is a requirement for equipment installed in a Class I, Division 2 location?

    <p>The equipment must be suitable for Division 2 locations only.</p> Signup and view all the answers

    What is the process of supplying an enclosure with a protective gas at a sufficient flow and positive pressure to reduce the initial concentration of any flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors to an acceptable level called?

    <p>Purging</p> Signup and view all the answers

    Which of the following is NOT a requirement for Class II equipment in hazardous locations?

    <p>The equipment must be suitable for both Division 1 and Division 2 locations.</p> Signup and view all the answers

    Which type of conduit is permitted when metal conduit does not provide the necessary corrosion resistance?

    <p>Listed reinforced thermosetting resin conduit (RTRC)</p> Signup and view all the answers

    Which type of conduit is permitted in restricted industrial establishments?

    <p>Schedule 80 PVC conduit</p> Signup and view all the answers

    Which types of optical fiber cable are permitted to be installed in cable trays or any other raceway?

    <p>Type OFNP and Type OFNR</p> Signup and view all the answers

    What is the minimum temperature at which a liquid gives off enough vapor to form an ignitible mixture with air?

    <p>Flash point</p> Signup and view all the answers

    What is the relationship between ignition temperature and flash point?

    <p>They are unrelated properties</p> Signup and view all the answers

    What is the maximum surface temperature under operating conditions for equipment with ignitible fibers/flyings present?

    <p>165°C (329°F)</p> Signup and view all the answers

    What is the suitable power disconnecting device for a detection system for flammable gases located inside a building or enclosed space?

    <p>Disconnect switch</p> Signup and view all the answers

    Which standard provides threading specifications for metric-threaded entries?

    <p>ISO 965-3</p> Signup and view all the answers

    Which type of cables need to be installed to address the associated fire hazard and sealed to address the associated explosion hazard?

    <p>Fiber optic cables</p> Signup and view all the answers

    What is the wavelength range for evaluating the risk of ignition from optical radiation in hazardous areas?

    <p>380 nm to 10 μm</p> Signup and view all the answers

    What is the minimum thickness of the concrete envelope required for PVC conduit, RTRC conduit, or HDPE conduit in Class I, Division 1 locations?

    <p>50 mm (2 in.)</p> Signup and view all the answers

    Which standard provides information on construction, testing, and marking of cables and cable fittings for use in hazardous (classified) locations?

    <p>ANSI/UL 2225</p> Signup and view all the answers

    In restricted industrial establishments, what type of cable is permitted for use where the cable is terminated with fittings listed for the location and installed in accordance with Part II of Article 337?

    <p>Listed Type P cable with metal braid armor and an overall jacket</p> Signup and view all the answers

    Which type of cable is permitted in industrial establishments where a flexible connection is necessary?

    <p>Type TC-ERHL</p> Signup and view all the answers

    What type of cable is permitted for Class 2 and Class 3 circuits, including installation in cable tray systems?

    <p>Type PLTC cable or Type PLTC-ER cable</p> Signup and view all the answers

    What is the purpose of marking the temperature class on electrical equipment installed in a Class II, Division 1 location?

    <p>To indicate the maximum safe operating temperature for the equipment</p> Signup and view all the answers

    What is the purpose of marking the maximum safe operating temperature on electrical equipment for Class I and Class II locations?

    <p>To indicate the maximum safe operating temperature for the equipment</p> Signup and view all the answers

    What type of equipment is not required to have a marked operating temperature or temperature class?

    <p>Equipment of the non-heat-producing type</p> Signup and view all the answers

    When is it acceptable for equipment in Class I or II, Division 1 or 2 locations to not be marked with the class, division, group, temperature class, or ambient temperature range?

    <p>When it is simple apparatus</p> Signup and view all the answers

    Which type of cable is required for the last 600 mm (24 in.) of the underground run to emergence or to the point of connection to the aboveground raceway?

    <p>Type MI cable</p> Signup and view all the answers

    In restricted industrial establishments, which type of cable is listed for use in Class I, Zone 1 or Division 1 locations, with a gas/vaportight continuous corrugated metallic sheath, an overall jacket of suitable polymeric material, and a separate equipment grounding conductor(s)?

    <p>Type MC-HL cable</p> Signup and view all the answers

    Which type of cable is listed for use in Class I, Division 1 or Zone 1 locations, with a gas/vaportight continuous corrugated metallic sheath and an overall jacket of suitable polymeric material?

    <p>Type ITC-HL cable</p> Signup and view all the answers

    Which type of cable is installed in raceways in accordance with 501.10(A) and shall be sealed in accordance with 501.15?

    <p>Optical fiber cable</p> Signup and view all the answers

    Which type of cable is permitted for Class 2 and Class 3 circuits, including installation in cable tray systems?

    <p>Type P cable</p> Signup and view all the answers

    What is the suitable power disconnecting device for a detection system for flammable gases located outside a building or enclosed space?

    <p>Extra-hard-usage flexible cord</p> Signup and view all the answers

    Which type of cable is listed for use in Class I, Division 1 or Zone 1 locations, with a gas/vaportight continuous corrugated metallic sheath and an overall jacket of suitable polymeric material?

    <p>Type EO cable</p> Signup and view all the answers

    Which type of wiring method is permitted for nonincendive field wiring in unclassified locations?

    <p>Conduit or cable tray</p> Signup and view all the answers

    When are explosionproof boxes and fittings required in Class I, Division 2 locations?

    <p>When they contain arcing devices</p> Signup and view all the answers

    What is the purpose of sealing compound used in Type MI cable termination fittings?

    <p>To exclude moisture and other fluids from the cable insulation</p> Signup and view all the answers

    What is the maximum operating temperature for equipment in Class I, Division 2 locations if it does not require explosionproof protection?

    <p>80 percent of the ignition temperature</p> Signup and view all the answers

    Which type of cable is specifically listed for use as a wiring method in Class I, Division 1 locations?

    <p>Type MC-HL cable</p> Signup and view all the answers

    What does 501.15(D)(1) require for cables installed in Class I, Division 1 locations?

    <p>Cables to be sealed at all terminations</p> Signup and view all the answers

    How do the sealing requirements for cables installed in Class I, Division 1 locations differ from the requirements for sealing conduits?

    <p>501.15(D)(1) requires cables to be sealed at all terminations, while 501.15(A) for conduits does not</p> Signup and view all the answers

    Which type of location requires conduit seals to be located in accordance with 501.15(B)(1) and (B)(2)?

    <p>Class I, Division 2</p> Signup and view all the answers

    For connections to explosionproof enclosures, what is required in Class I, Division 2 locations?

    <p>Conduit seals</p> Signup and view all the answers

    In Class I, Division 2 locations, where should a conduit seal be required?

    <p>At the boundary</p> Signup and view all the answers

    What is the requirement for the conduit run between the conduit seal and the point at which the conduit leaves the Division 2 location?

    <p>Contain no union, coupling, box, or other fitting</p> Signup and view all the answers

    Which type of fittings are required to have an integral sealing means or sealing fittings listed for the location?

    <p>Fittings with enclosures</p> Signup and view all the answers

    What is the minimum thickness of the sealing compound installed in completed seals, other than listed cable sealing fittings?

    <p>16 mm (5/8 in.)</p> Signup and view all the answers

    What is the maximum permitted fill for most conduit seals?

    <p>25 percent</p> Signup and view all the answers

    What type of cable shall be sealed with a listed fitting after the jacket and any other covering have been removed?

    <p>Type MC-HL cable</p> Signup and view all the answers

    Which of the following is a requirement for installing a conduit seal in a Division 1 location?

    <p>The seal must be located within 18 inches of the boundary</p> Signup and view all the answers

    In a Class I, Division 2 location, when is a conduit seal required between two enclosures?

    <p>When no additional conduit fittings exist between the enclosures</p> Signup and view all the answers

    Where should a conduit seal be located when the boundary is between a Division 1 and Division 2 location?

    <p>On the nonhazardous side of the boundary</p> Signup and view all the answers

    What is the purpose of a conduit seal in a hazardous location?

    <p>To prevent the transmission of flammable mixtures</p> Signup and view all the answers

    Which of the following is true about the passage of gas through a seal in smaller conductors under normal conditions?

    <p>It can be prevented by compacted strands or sealing individual strands</p> Signup and view all the answers

    Where should conduit seals be located in Class I, Division 1 locations?

    <p>Within 450 mm (18 in.) from the enclosure or as required by the enclosure marking</p> Signup and view all the answers

    Which of the following conditions does NOT require a conduit seal in Class I, Division 1 locations?

    <p>The switch, circuit breaker, fuse, relay, or resistor is part of a nonincendive circuit</p> Signup and view all the answers

    What is the maximum distance conduit seals should be installed from the enclosure in each conduit entry into a pressurized enclosure?

    <p>450 mm (18 in.)</p> Signup and view all the answers

    Which type of cables need to be sealed in the conduit within 450 mm (18 in.) of the enclosure and have the cable end sealed within the enclosure to minimize the entrance of gases or vapors and prevent the propagation of flame into the cable core?

    <p>Cables with an unbroken gas/vaportight continuous sheath</p> Signup and view all the answers

    What is the requirement for cables that are incapable of transmitting gases or vapors through the cable core when installed in conduit?

    <p>They need to be sealed in accordance with 501.15(A)</p> Signup and view all the answers

    In addition to sealing the conduit, what must also be sealed to prevent gases from passing through the cable?

    <p>The jacket and any other coverings</p> Signup and view all the answers

    Which type of surge arresters and surge-protective devices are permitted in Class I, Division 1 locations?

    <p>Spark-producing types</p> Signup and view all the answers

    Where should surge arresters be installed in Class I, Division 2 locations?

    <p>In general-purpose type enclosures</p> Signup and view all the answers

    What type of enclosures are required for meters, instruments, and relays in Class I, Division 1 locations?

    <p>Explosionproof enclosures and purged and pressurized enclosures</p> Signup and view all the answers

    What is the requirement for switches, circuit breakers, and make-and-break contacts of pushbuttons, relays, alarm bells, and horns in Class I, Division 1 locations?

    <p>Enclosures identified for Class I, Division 1 locations</p> Signup and view all the answers

    Which type of electrical equipment in a hazardous location is not required to have an additional means of sealing in case of a single process seal failure?

    <p>Process-connected equipment marked as 'dual seal'</p> Signup and view all the answers

    What is the suitable type of conductor insulation for areas where condensed vapors or liquids may collect on or come in contact with the insulation?

    <p>Type MI</p> Signup and view all the answers

    Which type of THWN wire is suitable for exposure to liquid gasoline and gasoline vapors at ordinary ambient temperature?

    <p>Type THWN marked as 'Gasoline and Oil Resistant I'</p> Signup and view all the answers

    What is the maximum voltage limit for uninsulated exposed parts in Class I, Division 1 and 2 locations?

    <p>30 volts</p> Signup and view all the answers

    Which of the following is NOT required for switches, circuit breakers, motor controllers, and fuses in Class I, Division 2 locations?

    <p>General-purpose enclosures</p> Signup and view all the answers

    Which type of enclosures are required for circuit breakers, motor controllers, and switches intended to interrupt current in the normal performance of their function in hazardous locations?

    <p>Enclosures identified for Class I, Division 1 locations</p> Signup and view all the answers

    Which type of enclosures are required for switches, circuit breakers, motor controllers, and fuses in Class I, Division 2 locations?

    <p>Enclosures identified for Class I, Division 2 locations</p> Signup and view all the answers

    Which of the following is NOT a requirement for grounding and bonding in hazardous locations?

    <p>The specific bonding methods mentioned in this section apply to raceways and raceway-to-enclosure connections both inside and outside the hazardous location</p> Signup and view all the answers

    Which of the following is true about the bonding requirements for hazardous locations?

    <p>The bonding requirement applies to the grounded circuit conductor and the grounding electrode conductor</p> Signup and view all the answers

    Which of the following is NOT a requirement for flexible metal conduit and liquidtight flexible metal conduit in hazardous locations?

    <p>The bonding jumper shall not be required in Class I, Division 2 locations</p> Signup and view all the answers

    Which of the following is NOT a requirement for equipment installed in a Class I, Division 1 location?

    <p>The equipment must comply with the requirements for Class I, Division 2 locations</p> Signup and view all the answers

    What is the purpose of the enhanced level of bonding for all raceways and enclosures in hazardous locations?

    <p>To provide a mechanical/electrical connection that is low impedance and free from accidental arcing</p> Signup and view all the answers

    Which of the following is a requirement for Class II equipment in hazardous locations?

    <p>The equipment must be suitable for the location</p> Signup and view all the answers

    What is the suitable power disconnecting device for a detection system for flammable gases located outside a building or enclosed space?

    <p>A circuit breaker complying with 501.105(B)(2)</p> Signup and view all the answers

    Which of the following is true about Class I, Group D materials?

    <p>They are atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial alloys</p> Signup and view all the answers

    Which type of cable installed in a Division 2 location is required to be sealed with a listed fitting after the jacket and any other coverings have been removed?

    <p>Multiconductor or optical multifiber cables with a gas/vaportight continuous sheath</p> Signup and view all the answers

    When are cables that do not transmit gases or vapors through the cable core required to be sealed?

    <p>When the cable is installed in a Division 1 location</p> Signup and view all the answers

    What is the minimum length of a cable run that does not transmit gases or vapors through the cable core in excess of the quantity permitted for seal fittings?

    <p>The length needed to limit gas or vapor flow through the cable core to 200 cm3/hr (0.007 ft3/hr) of air at a pressure of 1500 pascals (6 in. of water)</p> Signup and view all the answers

    In what type of location shall cables that do not have a gas/vaportight continuous sheath be sealed at the boundary of the Division 2 and unclassified location?

    <p>Class I, Division 2 locations</p> Signup and view all the answers

    Which of the following is NOT a requirement for Class I equipment in hazardous locations?

    <p>The interruption of current occurs within a chamber hermetically sealed against the entrance of gases and vapors.</p> Signup and view all the answers

    Which type of cable is required for the last 600 mm (24 in.) of the underground run to emergence or to the point of connection to the aboveground raceway?

    <p>Gas/vaportight continuous corrugated metallic sheath cable</p> Signup and view all the answers

    What is the purpose of a conduit seal in a hazardous location?

    <p>To prevent gases from passing through the cable</p> Signup and view all the answers

    Which standard provides information on construction, testing, and marking of cables and cable fittings for use in hazardous (classified) locations?

    <p>ANSI/UL 60079-30-1</p> Signup and view all the answers

    Which type of THWN wire is suitable for exposure to liquid gasoline and gasoline vapors at ordinary ambient temperature?

    <p>THWN-2</p> Signup and view all the answers

    Which type of cables need to be sealed in the conduit within 450 mm (18 in.) of the enclosure and have the cable end sealed within the enclosure to minimize the entrance of gases or vapors and prevent the propagation of flame into the cable core?

    <p>Mineral-insulated cables</p> Signup and view all the answers

    What is the suitable power disconnecting device for a detection system for flammable gases located inside a building or enclosed space?

    <p>Switch</p> Signup and view all the answers

    Which of the following is NOT a requirement for luminaires in Class I, Division 2 locations?

    <p>Luminaires must be identified for Class I locations</p> Signup and view all the answers

    What type of luminaires are generally required in Class I, Division 2 locations?

    <p>Enclosed and gasketed luminaires without guards</p> Signup and view all the answers

    What type of luminaires are required for areas with lamps that may reach high surface temperatures?

    <p>Luminaires with a marked operating temperature or temperature class (T code)</p> Signup and view all the answers

    How should pendant luminaires be suspended in Class I, Division 1 locations?

    <p>By threaded rigid metal conduit stems or other approved means</p> Signup and view all the answers

    Which of the following is a requirement for motor heaters in hazardous locations?

    <p>Motor heaters must be marked with the maximum temperature present in the motor.</p> Signup and view all the answers

    Which of the following is true about modern motors with high-temperature insulation systems?

    <p>Modern motors with high-temperature insulation systems can operate close to or above the ignition temperature of the flammable mixture.</p> Signup and view all the answers

    Which of the following is a requirement for luminaires in Class I, Division 1 locations?

    <p>Luminaires must be identified as a complete assembly for the Class I, Division 1 location.</p> Signup and view all the answers

    Which of the following is a requirement for pendant luminaires in hazardous locations?

    <p>Pendant luminaires must have set-screws or other effective means to prevent loosening of threaded joints.</p> Signup and view all the answers

    Which type of cable is permitted for use in nonincendive field wiring applications other than flexible cables?

    <p>Type R cables</p> Signup and view all the answers

    Which type of cable assembly is permitted to connect two pieces of electrical equipment in nonincendive field wiring applications?

    <p>501.141(B)(2)(a)</p> Signup and view all the answers

    What type of cable connector should be used on one end of the cable when connecting two devices or pieces of electrical utilization equipment together in Class I, Division 2 locations?

    <p>A cable connector listed for Class I, Division 2 and listed for the type of cable being used</p> Signup and view all the answers

    What is the requirement for terminations in Class I, Division 1 locations for flexible cables?

    <p>Terminations shall comply with 501.141(B)(2)(a), (B)(2)(b), or (B)(2)(c)</p> Signup and view all the answers

    Which of the following is NOT required for control transformers and resistors used in conjunction with control equipment for motors, generators, and appliances in Class I, Division 1 locations?

    <p>Compliance with 501.120(B)(1) through (B)(3)</p> Signup and view all the answers

    Which of the following is a requirement for motors, generators, and other rotating electrical machinery in Class I, Division 1 locations?

    <p>Being totally enclosed and having no external surface with an operating temperature exceeding 80 percent of the autoignition temperature of the gas or vapor involved</p> Signup and view all the answers

    Which of the following is a requirement for motors, generators, and other rotating electrical machinery in Class I, Division 2 locations?

    <p>Being identified for Class I, Division 2 locations or Class I, Division 1 locations with specific types of switching mechanisms</p> Signup and view all the answers

    What is the maximum permitted surface temperature for space heaters used to prevent condensation of moisture during shutdown periods in Class I, Division 2 locations?

    <p>80 percent of the autoignition temperature in degrees Celsius of the gas or vapor involved</p> Signup and view all the answers

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