ABC 3.1 - Article 501 Flashcards
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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 _____.

gases, vapors, liquids

Wiring methods and materials permitted in Class I, Division 1 locations include _____.

threaded rigid metal or threaded steel IMC, flexible fittings listed for Class I, Division 1 locations, boxes approved for Class I, Division 1 locations

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.

2, 24

MI cable terminated with fittings listed for the location is allowed in Class I, Division 1 locations.

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

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.

<p>is listed for use in Class I, Zone 1, or Division 1 locations, has a gas/vapor tight continuous corrugated metallic sheath, an overall jacket of suitable polymeric material, has a separate equipment grounding conductor(s) in accordance with 250.122</p> Signup and view all the answers

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 in accordance with 501.140 are permitted if terminated with cord connectors listed for the location.

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

When necessary to employ flexible connections in a Class I, Division 1 location, such as at motor terminals, _____ shall be permitted.

<p>flexible fittings listed for the location, flexible cord in accordance with the provisions of 501.140, terminated with cord connectors listed for the location, listed Type TC-ER-HL in industrial establishments with restricted public access</p> Signup and view all the answers

Wiring methods permitted in Class I, Division 1 locations are permitted in Class I, Division 2 locations.

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

_____ is(are) among the wiring methods permitted within a Class I, Division 2 location.

<p>Type MC, MV, TC, or TC-ER cable, including installation in cable tray systems and terminated with listed fittings, Optical fiber cable Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in cable trays or any other raceway in accordance with 501.10(B) and sealed in accordance with 501.15, Cablebus</p> Signup and view all the answers

In Class I, Division 2 locations, where metal conduit will not provide sufficient corrosion protection, _____ shall be permitted.

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

In a Class I, Division 2 location, if flexibility is necessary, _____ are some of the wiring methods that are permitted.

<p>listed flexible metal fittings, flexible metal conduit, liquidtight flexible metal conduit and liquidtight nonmetallic conduit, interlocked armor Type MC cable</p> Signup and view all the answers

When provisions for flexibility are necessary in Class I, Division 2 locations, FMC with listed fittings can be used.

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

In a Class I, Division 2 location, switches and circuit breakers shall be installed in explosionproof enclosures meeting the requirements for Class I, Division 1 locations.

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

General-purpose enclosures and fittings are permitted in Class I, Division 2 locations unless the enclosure contains make-and-break contacts for _____ as required by 501.105(B)(2), 501.115(B)(1), and 501.150(B)(1).

<p>meters, instruments, and relays, circuit breakers, or motor controllers, signaling, alarm, remote-control, and communications systems</p> Signup and view all the answers

In Class I hazardous (classified) locations, sealing compound shall be used in Type MI cable termination fittings to _____.

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

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 _____.

<p>enclosed within a chamber hermetically sealed against the entrance of gases or vapors, immersed in oil, enclosed within an enclosure, identified for the location, and marked 'Leads Factory Sealed,' or 'Factory Sealed,' 'Seal not Required,' or equivalent</p> Signup and view all the answers

Class I, Division 1 conduit seals shall be installed within _____ in.of the enclosure in each conduit entry into a pressurized enclosure where the conduit is not pressurized as part of the protection system.

<p>18</p> Signup and view all the answers

In Class I, Division 1 locations, conduit seals entering pressurized enclosures shall be installed within _____ in.from the enclosure or as required by the enclosure marking.

<p>18</p> Signup and view all the answers

Where two or more explosionproof enclosures that require conduit seals are connected by nipples or runs of conduit not more than _____ in.long, a single conduit seal in each such nipple connection or run of conduit shall be considered sufficient if the seal is located not more than 18 in.from either enclosure.

<p>36</p> Signup and view all the answers

A conduit run between a conduit seal and the point at which the conduit leaves a Class I, Division 1 location shall contain no union, coupling, box, or other fitting except for a listed _____ reducer installed at the conduit seal.

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

A sealing fitting shall be permitted to be installed within _____ ft of either side of the boundary where a conduit leaves a Class I, Division 1 location.

<p>10</p> Signup and view all the answers

Where the Class I, Division 1 location boundary is below grade, a sealing fitting shall be permitted to be installed _____, and there shall not be any unions, couplings, boxes, or fittings between the sealing fitting and the grade, other than listed explosionproof reducers.

<p>after the conduit emerges from grade</p> Signup and view all the answers

A conduit seal shall be required in each conduit run leaving a Class I, Division 2 location. The conduit sealing fitting shall be installed on either side of the boundary within _____ ft of the boundary.

<p>10</p> Signup and view all the answers

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.

<p>12</p> Signup and view all the answers

When sealing fittings are required for Class I locations, they shall comply with which of the following rule(s)?

<p>They shall be listed for Class I locations and shall be accessible, The minimum thickness of the sealing compound shall not be less than the trade size of the sealing fitting and, in no case, shall the thickness of the compound be less than 5/8 in., Splices and taps shall not be made in the conduit seal.</p> Signup and view all the answers

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.

<p>5/8</p> Signup and view all the answers

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.

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

In Class I, Division 1 locations, seals for cables at all terminations shall be installed within _____ in.of the enclosure or as required by the enclosure marking.

<p>18</p> Signup and view all the answers

In Class I, Division 1 locations, seals for cables at terminations, only explosionproof unions, couplings, reducers, elbows, and capped elbows that are not larger than the _____ of the conduit shall be permitted between the sealing fitting and the enclosure.

<p>Trade Size</p> Signup and view all the answers

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 of shielded cables and twisted pair cables isn't required within the conduit seal fitting.

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

Each multiconductor cable installed in conduit in a Class I, Division 1 location shall be considered as a single conductor if the cable is incapable of transmitting _____ through the cable core.

<p>gases or vapors</p> Signup and view all the answers

The removal of shielding material or the separation of the twisted pairs of shielded cables and twisted pair cables 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 and prevent flame propagation.

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

In Class I locations, the locknut-bushing and double-locknut types of contacts shall not be depended on for bonding purposes.

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

When FMC or LFMC is used as permitted in Class I, Division 2 locations, it shall include an equipment bonding jumper of the wire type in compliance with 250.102.

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

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.

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

Motors, generators, or other rotating electrical machinery identified for Class I, Division 2 locations can be used in Class I, Division 1 locations.

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

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.

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

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.

<p>maximum wattage of lamps</p> Signup and view all the answers

Luminaires installed in Class I, Division 1 locations shall be protected from physical damage by a suitable _____.

<p>guard or by location</p> Signup and view all the answers

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.

<p>set screws</p> Signup and view all the answers

Boxes, box assemblies, or fittings used to support luminaires in Class I, Division 1 locations shall be identified for Class I locations.

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

Luminaires installed in Class I, Division 2 locations shall be protected from physical damage by a suitable _____.

<p>guard or by location</p> Signup and view all the answers

In Class I, Division 1 locations, all utilization equipment shall be _____ for use in a Class I, Division 1 location.

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

Flexible cords are not permitted in Class I locations.

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

Flexible cords in Class I hazardous (classified) locations shall _____.

<p>be listed as extra-hard usage, contain an equipment grounding conductor, be supported by clamps or other suitable means to avoid tension on the terminals</p> Signup and view all the answers

In Class I, Division 1 or Division 2 locations where the boxes, fittings, or enclosures are required to be explosionproof, 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 explosionproof equipment is not required, the cord shall terminate _____.

<p>with a listed cord connector or listed attachment plug</p> Signup and view all the answers

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.

<p>of continuous length</p> Signup and view all the answers

In Class I locations, attachment plugs shall be of the type providing for _____ a permitted flexible cord and shall be identified for the location.

<p>connection to the equipment grounding conductor of</p> Signup and view all the answers

In Class I, Division 1 locations, all apparatus and equipment of signaling, alarm, remote-control, and communications systems _____ shall be identified for Class I, Division 1 locations.

<p>regardless of voltage</p> Signup and view all the answers

Study Notes

Class 1 Hazardous Locations Overview

  • Article 501 outlines requirements for electrical equipment and wiring in Class I hazardous locations where flammable gases, vapors, or liquids may be present.
  • Class I locations are divided into two divisions: Division 1 and Division 2, each with specific requirements.

Wiring Methods and Materials

  • Permitted wiring methods in Class I, Division 1 include rigid metal conduit, flexible fittings, and approved boxes.
  • MI cable must be terminated with approved fittings when used in Division 1 locations.
  • Flexible connections at motor terminals are allowed if they use suitable fittings and cord connectors.

Conduit Seals and Installations

  • Sealing compound is required for MI cable terminations to prevent moisture ingress.
  • Conduit seals must be installed within specified distances of enclosures, particularly in Division 1 applications.
  • Seals are necessary for conduit leaving Division 2 locations as well.

Equipment and Apparatus

  • Equipment in Division 1 must be identified specifically for that location; the same applies to all utilization equipment regardless of voltage for signaling and communication systems.
  • Circuit breakers must be installed within explosion-proof enclosures in Division 2 if not hermetically sealed or oil-immersed.
  • Luminaires in Division 1 must indicate maximum wattage and be physically protected.

Flexible Cords and Cables

  • Flexible cords are allowed in hazardous locations, provided they are listed for extra-hard usage and contain grounding conductors.
  • The use of flexible cords in temporary setups must maintain continuous length from power sources to equipment.
  • Shielding materials in twisted-pair cables don't need to be removed at conduit seals in both divisions if appropriately terminated.

Special Considerations

  • Non-metallic conduits may be permitted under specific conditions in underground Division 1 locations.
  • Conductors in sealing fittings should not exceed 25% of the cross-sectional area of the conduit.
  • The use of FMC or LFMC in Division 2 requires equipment bonding as per existing codes.

Prohibitions and Exceptions

  • General-purpose enclosures are generally permitted in Division 2 unless they contain make-and-break contacts as specified by regulations.
  • Unions and couplings are prohibited between sealing fittings and boundaries of hazardous locations to maintain safety standards.

These notes provide a structured overview of the requirements and allowances within Class I hazardous (classified) locations as delineated in Article 501.

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Test your knowledge of Article 501 regarding electrical and electronic equipment in Class I hazardous locations. These flashcards cover key terminologies and safety requirements essential for understanding fire and explosion risks. Ideal for students and professionals working with hazardous electrical installations.

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