Hazardous Locations Exam Review lesson 1-8
Separate nonincendive field wiring circuits shall be installed in multiconductor cables or in raceways, where the conductors of each circuit have insulation with a minimum thickness of _____ mm.
.25mm or 1/4mm
Seals shall be provided within ? of where a conduit leaves a Zone 0 location.
10'
Lamps and lampholders for fixed lighting, over Class I locations in commercial garages, that is located over lanes through which vehicles are commonly driven or that may otherwise be exposed to physical damage shall be located not less than ? above floor level, unless of the totally enclosed type or constructed so as to prevent escape of sparks or hot metal particles.
12'
metal conduit that contains no unions, couplings, boxes, or fittings, that passes completely through a class 1 division 1 location with no fittings installed within _____ of either side of the boundary, shall not require a conduit seal if the termination points of the unbroken conduit are located in unclassified locations
12'' (code ref. 501.15(A)(4)(EX. 1) )
Cables with gas/vapor tight continuous sheath capable of transmitting gasses or vapors through the cable core shall not be required to be sealed except as required in 501.15(E)(1), unless the cable is attached to process equipment or devices that may cause a pressure more than _____ Pa to be exerted at a cable end
1500
Mineral insulated cable (MI) is available with one to _____ conductors, making it most suitable for wiring of control boards, control components, and instrumentation circuits where crowded conditions make conduit instillations difficult and expensive
17 conductors
Where Type PVC conduit or Type RTRC conduit is used in bulk storage plants, threaded rigid metal conduit or threaded steel intermediate metal conduit shall be used for not less than the last ? (feet) of the conduit run to the conduit point of emergence from the underground location or to the point of connection to an above ground raceway.
2 foot. 515.8(A)
For open containers, supply containers, waste containers, spray gun cleaners, and solvent distillation units that contain Class I liquids that are located in ventilated areas, the area extending ? (feet) beyond the Division 1 or Zone 1 location shall be classified as Class I, Division 2 or Class I, Zone 2, whichever is applicable.
2 foot. 516.4(2)
Where the construction of piers, wharfs, or docks is open, enclosures such as tubs, voids, pits, vaults, boxes, depressions, piping chases, or similar spaces where flammable liquids or vapors can accumulate, within ? (feet) of the dispenser, shall be a Class I, Division 1 location.
20 foot. 514.3(E)(2)
Where the construction of piers, wharfs, or docks is open, enclosures such as tubs, voids, pits, vaults, boxes, depressions, piping chases, or similar spaces where flammable liquids or vapors can accumulate, within ? (feet) of the dispenser, shall be a Class I, Division 1 location.
20'. 514.3(E)(2)
Panels for light fixtures, that illuminate spray areas, shall be separated from the fixture to prevent the surface temperature of the panel from exceeding ? (degrees F).
200 degrees F
In bulk storage facilities, where operations include bottom loading with vapor control or bottom unloading, areas within ? of points of connections, extending in all directions and up to ? above grade within a horizontal radius of 10 ft. from point of connections are Class I, Division 2.
3' / 18". Table 515.3
An area for an indoor remote pump, in a motor fuel dispensing facility, up to ? above floor level, extending ? horizontally in all directions from any edge of pump is Class I, Division 2.
3' / 25' Table 514.3(B)(1)
Where outdoor equipment is installed where flammable vapor-air mixtures can exist under normal operation, the area between ? and ? of any edge, extending in all directions is classified as Class 1, Division 2.
3' / 8'
Uninsulated exposed parts, such as electrical conductors, buses, terminals, or components that operate at more than ? ( ? in wet locations) shall not be installed in Class II locations.
30 V / 15 V 502.30
Dust particles that fall within the definition of a combustible dust are materials that can pass through a U.S. No. _____ Standard Sieve as defined in ASTM E 11-09
35 (code ref. Art 100)
Major and minor repair garages that dispense motor fuels into the fuel tanks of vehicles, including flammable liquids having a flash point below ? (degrees Celsius) such as gasoline, or gaseous fuels such as natural gas, hydrogen, or LPG, shall have the dispensing functions and components classified in accordance with Table 514.3(B)(1) in addition to any classification required by this section.
38 degrees Celsius. 511.3(B)
The area within ? (feet), horizontally from aircraft power plants or aircraft fuel tanks shall be classified as a Class I, Division 2 or Zone 2 location that shall extend upward from the floor to a lower level ? (feet), above the upper surface of wings and of engine enclosures.
5' / 5'
Where a raceway, installed in a Class II location, provides communication between an enclosure, that is required to be dust-ignitionproof and one that is not, a vertical raceway not less that ? (feet) long and extending downward from the dust-ignitionproof enclosure, is a permitted means of preventing entrance of dust into the dust-ignitionproof enclosure.
5' 502.15(3)
the thickness of the sealing compound installed in completed seals, other than listed cable sealing fittings, shall not be less than the metric designator (trade size) of the sealing fitting expressed in the units of measurement employed; however, in no case shall the thickness of the compound be less than _____
5/8''
Where the cord for electric vehicle charging equipment is suspended from overhead, in commercial garages, it shall be arranged so that the lowest point of sag is at least ? (inches) above the floor.
6" 511.10(B)(3)
Dry-type transformers installed in Class II, Division 2 locations shall be in vaults or shall have their windings and terminal connections enclosed in tight metal housings without ventilation or other openings and shall operate at not over ? (volts), nominal.
600volts 502.100 (B)(3)
Ventilating pipes for motors, generators, or other rotating electrical machinery, or for enclosures for electrical equipment, installed in Class II, Division 1 locations, shall ? .
Be protected against physical damage and against rusting or other corrosive influences, Be screened at the outer ends to prevent the entrance of small animals or birds, & Lead directly to a source of clean air outside of buildings. 502.128
Attachment plugs and receptacles in the Class I locations of aircraft hangers shall be identified for Class I locations or shall be designed such that they ? while the connections are being made or broken.
Cannot be energized 513.4(A)
an area where ignitable concentrations of flammable gases, flammable liquid-produced vapors, or combustible liquids above their flash points may exist frequently because of repair or maintenance operations, or because or leakage, would be classified as _____
Class 1 Division 1
The area between three feet and eight feet of any edge, extending in all directions, of outdoor equipment of the type covered in Section 5.3 of NFPA 30, installed in bulk storage plants where flammable vapor-air mixtures may exist under normal operation, and the space up to three feet above the floor or grade level with in three feet to ten feet, horizontally from any edge of such equipment, is classified as ? .
Class I, Division 2. Table 515.3
Where vehicles using ? liquids or heavier-than-air gaseous fuels (such as LPG) are repaired in the hazardous area of a major or minor repair garage, classification guidance is found in Table 511.3(C).
Class I. 511.3
Equipment enclosed in a manner that excludes dust and does not permit arcs, sparks, or heat otherwise generated or liberated inside of the enclosure to cause ignition of exterior accumulations or atmospheric suspensions of a specified dust on or in the vicinity of the enclosure is _____
Dust-Ignition proof
Where a raceway provides communication between an enclosure that is required to be ? and one that is not, suitable means shall be provided to prevent the entrance of dust into the ? enclosure through the raceway.
Dust-ignitionproof / dust-ignitionproof 502.15
Type TC-ER cable used in a Class III, Divisions 1 location must include a(n) ? in addition to a ? that may be present.
Equipment grounding conductor / drain wire. 503.10 (A)(1)
All air mixtures shall be grouped in accordance with 500.6(A) and (B) for the purposes of testing, approval, and area classification.
False
In Class I, Division 1 locations or in Class II, Division 1 locations where boxes, fittings, or enclosures are required to be explosionproof, flexible cords shall be terminated with cord connectors or attachment plugs listed for the location or listed cord connectors installed with seals listed for the locations. T/F
False
Nonincendive equipment has electrical/electronic circuitry that may, under normal operating conditions, casue ignition of a specified flammable gas air, vapor air, or dust air mixture due to arcing or thermal means. T/F
False
Resistors shall be provided with enclosures; and the assembly shall be identified for Class I locations, unless resistance is nonvariable and maximum operating temperature, in degrees Celsius, will not exceed 80 percent of the flashpoint of the gas or vapor involved or the resistor has been tested and found incapable of igniting the gas or vapor. T/F
False
The cross-sectional area of the conductors or optical fiber tubes (metallic or nonmetallic) permitted in a seal shall not exceed 25% of the cross-sectional area of a rigid metal conduit of the same trade size unless the seal is specifically identified for a higher percentage of fill. T/F
False
Transformers and capacitors, containing liquid that will not burn, shall only be permitted in Class II, Division 1 where they are installed in vaults complying with 450.41 through 450.48 . T/F
False
when storing equipment that is designed for use in hazardous (classified) locations, the covers and mating bodies should be wrapped and stored separately
False
Enclosures used in class 1 division 1 and 2 locations are not required to be designed to prevent an explosion within the enclosure from starting a larger explosion on the outside
False (they ARE required to prevent this)
Lampholders for portable lighting in Class III locations shall be of the unswitched type with provisions for receiving attachment plugs. T/F
False 503.130 (D)
The ? of a liquid is the minimum temperature at which it gives off sufficient vapor to form an ignitable mixture with the air near the surface of the liquid or within the vessel used.
Flash point
The temperature mark specified in 500.8(C) for class 2 locations shall be less than the _____ of the specific dust to be encountered
Ignition Temperature 500.8(D)(2)
the use of _____ in the layout of electrical installations for Hazardous (classified) locations can result in the placement of equipment to allow it to have a lower level of classification, or to be unclassified
Intrinsically safe equipment
A spray booth is a power-ventilated enclosure for a spray application operation or process that confines and limits the escape of the material being sprayed, including vapors, mists, dusts, and residues that are produced by the spraying operation and conducts or directs these ? to an exhaust system.
Materials. 100
each luminaire shall be indentified as a complete assembly for the class 1 division 1 location and shall be clearly marked to indicate the _____ of lamps for which it is identified
Maximum Wattage
Class II, Group E locations would contain ? -type materials.
Metallic
Standard open-type machines without sliding contacts, centrifugal or other types of switching mechanics, including ? are permitted in Class III location where, in the judgement of the authority having jurisdiction, only moderate accumulations of lint or flyings are likely to collect on, in, or in the vicinity of a rotating electrical machine and where such machine is readily accessible for routine cleaning and maintenance.
Motor overload devices
Separate nonincendive field wiring circuits in Class III, Division 1 locations shall be installed in ? .
Multiconductor cables where the conductors of each circuit are within a grounded metal shield & Separate cables
Combustible gas detectors are permitted as a means of protection under which of the following conditions?
Only qualified persons service the equipment, There is restricted public access
Conductors of intrinsically safe circuits shall be ? so that any conductor that might come loose from a terminal is unlikely to come into contact with another terminal.
Secured
Where a conduit run enters or leaves a dispenser, a sealing fitting or ? explosionproof reducer at the seal shall be the first fitting after the conduit emerges from the earth or concrete.
Listed
Flexible cords used in Class II, Division 2 locations, shall be terminated with a(n) ? dusttight cord connector.
Listed 502.140 (B)(4)
Identified elevator cables of Type EO, ETP, or ETT, shown under the "use" column in Table 400.4 for "hazardous (classified) locations" and terminated with ? fittings may be used for elevator instillations in Class III, Division 1 locations.
Listed dusttight
type _____ cable listed for use in Zone 1 or class 1, Division 1 locations, with a gas/vapor tight continuous corrugated metallic sheath, and an overall jacket of suitable polymeric material can be used in industrial establishments with restricted public access, where the conditions of maintenance and supervision ensure that only qualified persons service the installation, under certain conditions.
MC_HL
Where open containers, supply containers, spray gun cleaners, and solvent distillation units that contain Class I liquids are located in ventilated areas, electrical wiring and utilization equipment shall be ? for the location.
Suitable
In Class III, Division 1 and 2 locations, motors, generators, and other rotating machinery shall be ? .
Totally enclosed fan cooled, Totally enclosed non-ventilated, & Totally enclosed pipe ventilated. 503.125
Improper positioning of a seal may permit hazardous gases or vapors to enter the system beyond the seal, and permit them to escape into another portion of the hazardous area, or to enter a nonhazardous area. T/F
True
Purged and pressurized systems require the installation of door-interlock switched to prevent access to the equipment while the circuits are energized
True
Luminaries, installed in Class II, Division 2 locations, with rigid stems longer than 12" shall have bracing against lateral displacement provided at a level not more than 12" above the lower end of the stem, an identified fitting or a flexible connector provided not more than 12" from the point of attachment to the supporting box or fitting. T/F
True 502.130 (B)(4)
Ventilating pipes in Class III locations shall be sufficiently tight, including their connections, to prevent the entrance of appreciable quantities of fibers/flyings into the ? equipment or enclosure.
Ventilated 503.128
Dusts containing ______ are particularly hazardous and use of extreme precaution is necessary to avoid ignition and explosion
aluminum and magnesium
Vaults that house transformers or capacitors containing liquids that will burn shall have vent ducts and openings of sufficient area to relieve explosion pressure within the vault, and all portions of vent ducts within the buildings shall ______
be of reinforced concrete construction
Class II hazardous, Group G atmospheric hazards are based on the presence of _____ materials
combustible dust i.e. (flour, grain, wood, plastic, chemicals)
in order for the possibility of a fire or explosion to occur, _____ must be present in sufficient quantities to mix with oxygen and be subjected to a source of energy.
combustible dust, combustible liquid-produced vapors, and flammable liquid-produced vapors
The electrical equipment and wiring in the interior of a control panel containing instrumentation or other equipment that utilizes or measures flammable liquids, gases, or vapors, is permitted to be rated for class 1, division 2 where the panel is protected by _____
combustible gas detection equipment
Open type motors, such as squirrel-cage induction motors, without arcing devices may be used in class 1 division 1 locations.
false
where seals are required for boundary conditions as identified in 501.15(A)(4), the Division 1 wiring method shall extend into the Division 2 area to seal, which shall be located on the Division ! side of the Division 1- Division 2 boundary.
false
Nonincendive field wiring enters or leaves an equipment enclosure and, under abnormal operation conditions of the equipment, is not capable, due to arcing or thermal effects, of igniting the flammable gas-air, vapor-air, or dust-air mixture.
false (code ref. Art 100)
operating energy for intrinsically safe equipment is provided by power supplies located in _____
neither class 1 division 2 or class 2 division 2 locations
In extremely corrosive locations, equipment should be periodically inspected to guard against _____, since this may weaken the enclosure structurally
possible porosity, and unusual deterioration
Class 1 Division 1 locations are those where flammable gases or vapors may exist _____
under frequent repair or maintenance operations, under normal conditions, and where breakdown or faulty operation of process equipment might cause electrical equipment failure simultaneously Code Ref. 500.5(B)(1)
Conductors of intrinsically safe circuits may be placed in any raceway, cable tray, or cable with conductors of any non-intrinsically safe circuit where either (1) all of the intrinsically safe circuit conductors or (2) all of the non-intrinsically safe circuit conductors are in ? metal-sheathed or metal-clad cables where the sheathing or cladding is capable of carrying fault current to ground.
Grounded
Switches, circuit breakers, motor controllers, fuses, push buttons, relays, and similar devices, installed in Class II, Division 1 locations, shall be provided with enclosures ? for the location.
Identified 502.115 (B)
Portable lighting equipment that is used within a hangar shall be ? .
Identified for the location in which they are used
In Class III locations where ? only moderate accumulations of lint or flyings are likely to collect in the vicinity of a receptacle, and where such receptacle is readily accessible for routine cleaning, general purpose grounding-type receptacles mounted so as to minimize the entry of fibers/flyings shall be permitted.
In the judgement of the authority having jurisdiction
A nonincendive component having contacts for making or breaking a/an _____ and the contacting mechanism is constructed so that the component is incapable of igniting the specified flammable gas-air or vapor-air mixture. The housing of a nonincendive component is not intended to exclude the flammable atmosphere or contain an explosion.
Incendive circuit Art 100
Motors, generators and other rotating machinery are permitted to be installed in Class I, Division 1 locations, if they are of the totally enclosed insert gas-filled type supplied with a suitable reliable source of inert gas for pressurizing the enclosure, with devices provided to ensure a ? pressure in the enclosure and arranged to automatically deenergize the equipment when the gas supply fails.
Positive 501.125 (A)(3)
the equipment and its associated wiring for intrinsically safe equipment must be installed so they are ______ seperated from the non-intrinsically safe circuits.
Positively
An intrinsically safe circuit is one in which any ? is incapable of causing ignition of a mixture of flammable or combustible material in air under prescribed test conditions.
Spark or thermal effect
the purged and pressurized protection technique shall be permitted for equipment in any hazardous (classified) location for which it is _____
identified ( code ref. Art 500.7(D) )
Class 3 locations are hazardous because of the presence of easily ignitible fibers or where materials producing combustible flyings are handled, manufactured, or used, but are not likely to be in suspension in the air in quantities sufficient to produce _____ mixtures
ignitable ( code ref. Art 500.5(D) )
many devices or parts of an electrical system, which do not have make-or-break contacts, may become sources of ignition where there is _____
overloading, and insulation failure
During cleaning and lubrication maintenance, body and cover joints should be reassembled immediately to ensure that _____ are not attracted to the surface
particles of dirt, or foreign materials
