Questions and Answers
In Class II locations, a permitted method of bonding is the use of bonding jumpers with proper fittings.
True
In Class II, Division 1 locations, switches, circuit breakers, motor controllers, and fuses, including push buttons, relays, and similar devices shall be provided with enclosures that are ____________.
identified for the location
In Class II, Division 2 locations, enclosures for fuses, switches, circuit breakers, and motor controllers, including pushbuttons, relays, and similar devices shall be ____________.
dust tight or otherwise identified for the location
In Class II, Division 1 locations, control transformers, solenoids, impedance coils, resistors, and any overcorrect devices or switching mechanisms associated with them, shall have enclosures identified for ____________.
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Luminaires installed in Class II, Division 1 locations shall be identified for the location and shall be clearly marked to indicate the ____________.
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Luminaires installed in Class II, Division 1 locations shall be protected from physical damage by a suitable ____________.
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Pendant luminaires installed in Class II, Division 1 locations shall be suspended by threaded RMC or steel IMC conduit stems, by chains with approved fittings, or by other approved means. Stems shall be provided with ____________ or other effective means to prevent loosening.
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Luminaires for fixed lighting in Class II, Division 2 locations shall be equipped with enclosures that are ____________ or otherwise identified for the location.
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Luminaires for fixed lighting installed in Class II, Division 2 locations shall be protected from physical damage by a suitable ____________.
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Flexible cords used in Class II, Division 1 or 2 locations shall ____________, except as permitted for pendant luminaires.
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In Class II, Division 1 locations, receptacles shall be part of the premises wiring and attachment plugs shall be of the type that provides for connection to the ____________ of the flexible cord.
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Signaling, alarm, remote-control, and communications system circuits containing contacts installed in Class II, Division 2 locations shall be in enclosures that are ____________ or otherwise identified for the location.
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Article 503 covers the requirements for electrical and electronic equipment and wiring in Class III locations where fire or explosion hazards may exist due to ignitable ____________.
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Raceways permitted in a Class III, Division 1 location include ____________.
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Boxes and fitting shall be ____________ where installed in a Class III location.
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Where LFMC is used in a Class III location as permitted in 503.10 it shall ____________.
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In Class III locations, ____________ used as, or in conjunction with, control equipment for motors, generators, and appliances shall be provided with dusttight enclosures complying with the temperature limitations in 503.5.
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In Class III locations, motors, generators, and other rotating machinery shall be totally enclosed ____________.
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Luminaires for fixed lighting in Class III locations shall have enclosures for lamps and lamp holders that are designed to prevent the escape of ____________.
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Luminaires in Class III locations exposed to physical damage shall be protected by a(n) ____________ guard.
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In a Class III location, pendant luminaires suspended by stems longer than ____________ ft shall be provided with a fitting or flexible connector identified for the location, or shall be provided with effective bracing.
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In Class III locations, flexible cords shall ____________.
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In Class III locations, receptacles and attachment plugs shall be of the grounding type, shall be designed so as to minimize the accumulation or the entry of ____________, and shall prevent the escape of sparks or molten particles.
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Article ____________ contains the wiring requirements for service and repair operations in connection with self-propelled vehicles in which volatile flammable liquids or flammable gases are used for fuel or power.
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A building or portions of a building where engine overhauls, painting, body and fender work, and repairs that require ____________ of the motor vehicle fuel tank are performed defines the term 'Major Repair Garage.'
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Parking garages used for parking or storage can be considered as an unclassified location.
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In major repair garages where ventilation is not provided, any pit or depression below floor level shall be a Class I, ____________ location.
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Where Class I liquids or gaseous fuels will not be transferred in a minor repair garage, such location is considered to be a(n) ____________ location, provided the entire floor area has mechanical ventilation providing a minimum of four air changes per hour or one cubic foot per minute of exchanged air for each square foot of floor area.
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In major repair garages where lighter-than-air gaseous fueled vehicles, such as vehicles fueled by natural gas or hydrogen, are repaired or stored, the area within ____________ in. of the ceiling is classified as Class I, Division 2 unless otherwise noted.
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The area used for ____________ of alcohol-based windshield washer fluid in repair garages shall be unclassified.
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Type NM cable can be installed above a Class I location in a commercial garage.
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Flexible cords for pendants installed above Class I locations in a commercial garage shall be ____________.
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Fixed electrical equipment installed in spaces above a Class I location in a commercial garage shall be ____________.
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A permanently mounted luminaire in a commercial garage, located over lanes on which vehicles are commonly driven, shall be located not less than ____________ ft above floor level.
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Underground wiring in a commercial garage shall be installed in ____________.
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In commercial garages, Type PVC conduit, Type RTRX conduit, and Type HDPE conduit shall be permitted where buried under not less than ____________ ft of cover.
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In commercial garages, where Type PVC conduit, Type RTRC conduit, or Type HDPE conduit is used underground, threaded rigid metal conduit or threaded steel intermediate metal conduit shall be used for the last ____________ ft of the underground run to emergence or to the point of connection to the above ground raceway, and an equipment grounding conductor shall be included.
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Battery chargers and the batteries being charged can be located in any area of a commercial garage.
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All areas designated as hazardous (classified) locations shall be properly ____________.
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Hazardous (classified) locations shall be classified depending on the properties of the ____________ that could be present.
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It is frequently possible to locate much of the equipment in less hazardous or unclassified locations and thus reduce the amount of special equipment required.
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When determining a Class I, Division 2 location, the ____________ is a factor that should be considered.
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Class II locations are those that are hazardous because of the presence of ____________.
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Locations in which combustible dust is in the air under normal operating conditions in quantities sufficient to produce explosive or ignitable mixture are classified as ____________.
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Class III locations are those that are hazardous because of the presence of ____________.
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Class III, Division ____________ locations include areas where easily ignitable fibers/flyings are handled, manufactured, or used.
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A Class III, Division ____________ location is where easily ignitable fibers/flyings are stored or handled but not manufactured.
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Acceptable protection techniques for electrical and electronic equipment in hazardous (classified) locations include ____________ equipment.
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Suitability of identified equipment for use in a hazardous (classified) location shall be determined by ____________.
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Equipment shall be identified not only for the class of hazardous (classified) location, but also for the explosive, combustible, or ignitable properties of the specific ____________ present.
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Threaded conduits or fittings installed in hazardous (classified) locations shall be made wrench tight to ____________.
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Equipment used in hazardous (classified) locations with metric threaded entries shall be installed using ____________.
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An optical fiber cable, with or without current-carrying conductors (composite optical fiber cable), shall be installed to address the associated fire hazard and sealed to address the associated explosion hazard.
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Article 501 covers the requirements for electrical and electronic equipment and wiring for all voltages in Class I locations where fire or explosion hazards may exist due to flammable ____________.
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Wiring methods and materials permitted in Class I, Division 1 locations include ____________.
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Type PVC conduit, Type RTRC conduit, and Type HDPE conduit shall be permitted in Class I, Division 1 underground locations where encased in a concrete envelope a minimum of _________ in. thick and provided with not less than _________ in. of cover measured from the top of the conduit to grade.
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MI cable terminated with fittings listed for the location is allowed in Class I, Division 1 locations.
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In industrial establishments with restricted public access where only qualified persons will service the installation, MC-HL cable is allowed to be used in a Class I, Division 1 location if it ____________, and terminated with fittings listed for the application.
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In industrial establishments with restricted public access, where the conditions of maintenance and supervision ensure that only qualified persons service the installation, Type ITC-HL cable is allowed to be used in a Class I, Division 1 location if it ____________ and installed in accordance with the provisions of Article 727.
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When necessary to employ flexible connections in a Class I, Division 1 location, such as at motor terminals, flexible fittings listed for the location or flexible cord are permitted.
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When necessary to employ flexible connections in a Class I, Division 1 location, such as at motor terminals, ____________ shall be permitted.
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Wiring methods permitted in Class I, Division 1 locations are permitted in Class I, Division 2 locations.
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In Class I, Division 2 locations, where metallic conduit doesn't provide sufficient corrosion resistance, reinforced thermosetting resin conduit with the suffix '-XW' and Schedule 80 PVC conduit can be used.
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When provisions for flexibility are necessary in Class I, Division 2 locations, FMC with listed fittings can be used.
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In a Class I, Division 2 location, switches and circuit breakers shall be installed in explosion proof enclosures meeting the requirements for Class I, Division 1 locations.
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General-purpose enclosures and fittings are permitted in Class I, Division 2 locations unless the enclosure contains make-and-break contact for ____________.
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In Class I hazardous (classified) locations, sealing compound shall be used in Type MI cable termination fittings to ____________.
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In Class I, Division 1 locations, seals shall not be required for conduit entering an enclosure if the switch, circuit breaker, fuse, relay, or resistor is ____________.
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In Class I, Division 1 locations, conduit seals shall be installed within ____________ in. from the enclosure or as required by the enclosure marking.
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A sealing fitting shall be permitted to be installed within ____________ of either side of the boundary where a conduit leaves a Class I, Division 1 location.
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A sealing fitting shall not be required if a metal conduit passes completely through a Class I, Division 2 location if the termination points of the unbroken conduit are located in unclassified locations and it has no fittings less than ____________ in. of either side of the boundary of the hazardous (classified) location.
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When sealing fittings are required for Class I locations, they shall comply with which of the following rule(s)?
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The minimum thickness of sealing compound in Class I locations shall not be less than the trade size of the conduit or sealing fitting and, in no case, shall the thickness of the compound be less than ____________ in.
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The cross-sectional area of the conductors or optical fiber tubes permitted in a sealing fitting shall not exceed ____________ percent of the cross-sectional area of RMC of the same trade size.
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In Class I, Division 1 locations, seals for cables entering enclosures shall be installed within ____________ in. of the enclosure or as required by the enclosure marking.
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When installing shield cables and twisted-pair cables in conduit in a Class I, Division 1 hazardous (classified) location, the removal of shielding material or the separation of the twisted pairs isn't required within the conduit seal fitting.
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The removal of shielding material or the separation of the twisted pairs isn't required within the conduit seal fitting in a Class I, Division 2 hazardous (classified) location provided the termination is by an approved means to minimize the entrance of gases or vapors.
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In Class I locations, the locknut-wishing and double-locknut types of contacts shall not be depended on for bonding purposes.
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Transformers and capacitors installed in Class I, Division 1 locations containing a liquid that will burn shall be installed in vaults.
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Transformers and capacitors installed in Class I, Division 1 locations that do not contain flammable liquids shall not be required to be installed in vaults if they are identified for Class I locations.
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Circuit breakers in Class I, Division 2 locations that are not hermetically sealed or oil-immersed shall be installed in a Class I, Division 1 enclosure.
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In Class I, Division 1 locations, transformers, impedance coils, and resistors, along with any switching mechanism associated with them, shall be provided with enclosures identified for ____________.
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Motors, generators, or other rotating electrical machinery identified for Class I, Division 2 locations can be used in Class I, Division 1 locations.
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Totally enclosed motors of the types specified in 501.125(A)(2) or (A)(3) shall have a device to de-energize the motor or provide an alarm if there is any increase in temperature of the motor beyond designed limits when operating in Class I, Division 1 locations.
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Luminaires installed in Class I, Division 1 locations shall be identified as a complete assembly for the Class I, Division 1 location and shall be clearly marked to indicate the ____________ for which it is identified.
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Luminaires installed in Class I, Division 1 locations shall be protected from physical damage by a suitable ____________.
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Pendant luminaires in a Class I, Division 1 location shall be suspended by and supplied through threaded rigid metal conduit stems or threaded steel intermediate conduit stems, and threaded joints shall be provided with ____________ or other effective means to prevent loosening.
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Boxes, box assemblies, or fittings used to support luminaires in Class I, Division 1 locations shall be identified for Class I locations.
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Luminaires installed in Class I, Division 2 locations shall be protected from physical damage by a suitable ____________.
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In Class I, Division 1 locations, all utilization equipment shall be ____________ for use in a Class I, Division 1 location.
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Flexible cords in Class I hazardous (classified) locations shall ____________.
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In Class I, Division 1 or Division 2 locations where the boxes, fittings, or enclosures are required to be explosion proof, if a flexible cord is used it shall terminate with a cord connector or attachment plug listed for the location, or a listed cord connector installed with a seal that is listed for the location. In Division 2 locations where explosion proof equipment is not required, the cord shall terminate ____________.
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For Class I locations where 501.140(A)(5) is applied, flexible cords shall be ____________ from the power source to the temporary portable assembly and from the temporary portable assembly to the utilization equipment.
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In Class I locations, attachment plugs shall be of the type providing for ____________ a permitted flexible cord and shall be identified for the location.
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In Class I, Division 1 locations, all apparatus and equipment of signaling, alarm, remote-control, and communication systems ____________ shall be identified for Class I, Division 1 locations.
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Raceways permitted as a wiring method in Class II, Division 1 locations include ____________.
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Raceways permitted as a wiring method in Class II, Division 2 locations include ____________.
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Where flexibility is required, the following wiring methods are permitted in a Class II, Division 2 location ____________.
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In Class II locations, dust shall be prevented from entering the required dust-ignitionproof enclosure through a raceway by which of the following methods?
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Seals in Class II hazardous (classified) locations shall be explosion proof.
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Study Notes
Hazardous Locations Overview
- Hazardous locations must be documented and accessible to authorized personnel.
- Classification of hazardous locations is based on properties of flammable substances and their likelihood of presence.
Classifications of Hazardous Locations
- Class I: Involves flammable gases, vapors, and combustible liquids.
- Class II: Defined by the presence of combustible dust.
- Class III: Involves easily ignitable fibers or materials.
Class I Hazardous Locations
- Division 1: Areas with flammable materials present, requiring stricter safety measures.
- Division 2: Areas where flammable materials are not present under normal conditions but may escape in case of an accident.
Equipment and Installation Requirements
- All equipment in hazardous locations must be suitable, listed, and marked for their specific classification.
- Acceptable protection techniques include explosion-proof and dust-tight equipment.
- Flexible connections and wiring methods must adhere to specific codes for safety in hazardous environments.
Sealing and Bonding
- Sealing fittings are necessary for cable terminations, especially in Division 1 locations to prevent moisture and vapor ingress.
- Conductors in sealing fittings must not exceed 25% of the cross-sectional area of the conduit.
- Bonding methods must ensure electrical continuity to maintain safety.
General Equipment Provisions
- Equipment is required to meet various safety standards and should be properly installed to avoid risks associated with explosions and fires.
- Enclosures, fittings, and raceways must be dust-tight and suitable for the specific location classification.
- Electrical devices like circuit breakers and motors in Class I and Class II locations must also be specifically identified and protected.
Lighting and Luminaire Requirements
- Luminaires in hazardous locations must be identified for their maximum lamp wattage and protected against physical damage.
- Pendant luminaires in Class I must be securely suspended to prevent loosening.
Additional Considerations
- In certain locations, specific types of cables may be used if they comply with listed safety requirements.
- Flexible cords must be secured to prevent tension on terminals and certified for hazardous usage.
- Continuous length cords are favored to reduce potential connection points that may introduce hazards.
Compliance and Maintenance
- Regular inspections and equipment evaluations from qualified agencies are essential for ongoing safety.
- All installations must comply with the latest safety codes and guidelines to mitigate risk in hazardous environments.### Electrical Safety and Classifications
- Class II, Division 2 luminaires must be protected from physical damage via suitable guards or by their installation location.
- Flexible cords in Class II locations must be specifically rated for extra-hard usage, except for pendant luminaires.
- In Class II, Division 1, receptacles must be wired into the premises with plug types that facilitate connection to the equipment grounding conductor.
Class III Electrical Equipment
- Signaling and communication circuits in Class II, Division 2 require dusttight enclosures to avoid contamination.
- Article 503 outlines criteria for electrical equipment in Class III locations due to hazards from ignitable fibers and flyings.
- Appropriate raceways for Class III, Division 1 include RMC, IMC, Type MC cable, and electrical metallic tubing.
Protection and Requirements for Class III
- Boxes and fittings installed in Class III locations must be dusttight to prevent the ingress of materials.
- LFMC in Class III must have an equipment bonding jumper in accordance with specific grounding requirements.
- Dusttight enclosures are necessary for control equipment like transformers and resistors in Class III applications.
Equipment Specifications
- Motors and generators in Class III must be totally enclosed, and they can be non-ventilated, pipe-ventilated, or fan-cooled.
- Luminaires in Class III locations need enclosures preventing sparks, burning materials, and hot metal escapes.
- Pendant luminaires in Class III must use appropriate supports if suspended more than 1 foot above the ground.
Flexible Cords and Receptacles
- In Class III areas, flexible cords should be extra-hard usage, include grounding conductors, and connect with listed dusttight connectors.
- Equipment including receptacles and plugs must minimize fiber accumulation and prevent spark escape in Class III.
Garage and Repair Operations
- Article 511 specifies wiring for service and repair operations with flammable liquids or gases.
- Major repair garages defined by engine overhauls and tank draining must adhere to safety classifications.
- Parking garages are unclassified locations, indicating relaxed safety requirements compared to classified areas.
Ventilation and Hazards
- In major repair garages without ventilation, areas below the floor are classified as Class I, Division 1.
- Locations not transferring Class I substances and ventilated adequately can be labeled unclassified.
Installations in Commercial Garages
- Type NM cable cannot be installed above Class I locations in commercial garages due to fire hazards.
- Luminaires above vehicle lanes must be mounted at least 12 feet above the floor for safety.
- Underground wiring in commercial garages must use threaded rigid or intermediate metal conduits for protection.
Conduit Specifications and Safety
- PVC, RTRX, and HDPE conduits can be used underground with a minimum cover of 2 feet.
- The last 2 feet of underground runs must transition to threaded metal conduits with grounding continuity for safety.
- Battery chargers in commercial garages are restricted from any area, indicating specific placement rules for safety.
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Test your knowledge on electrical safety standards in hazardous locations with this Chapter 5 quiz. Each card includes a word and its definition, helping you understand essential concepts and terminology. Perfect for those studying electrical engineering or safety protocols.
