Jul,21

IEEE Std 2740 pdf download

IEEE Std 2740 pdf download

IEEE Std 2740 pdf download IEEE Guide for Selection and Installation of Electrical Cables and Cable Systems in Hazardous (Classified) Locations on Oil and Gas Land Drilling Rigs
3.Definitions, acronyms, and abbreviations
3.1 Definitions
For the purposes of this document,the following terms and definitions apply. The IEEE StandardsDictionary Online should be consulted for terms not defined in this clause.10
3.2 Acronyms and abbreviations
adjustable speed drive (ASD): Electronic power conversion equipment that provides a means of adjustingthe speed of an electric motor.
AEx: Required marking prefix for electrical apparatus to be installed in hazardous (classified) locationsmeeting one or more types of protection in accordance with harmonized American National Standards(ANSI) as defined in Article 505 of the NEC.
approved: Acceptable to the authority having jurisdiction.(Electrical devices that are approved by aNationally Recognized Testing Laboratory normally are acceptable.)
NOTE—The means for identifying approved equipment can vary for each organization concerned with productevaluation, some of which do not recognize equipment as approved unless it is also labeled. The authority havingjurisdiction normally utilizes the system employed by the certifying organization to identify an approved product.”
Class l location: A Class l location is one in which flammable gases or vapors are or may be present in theair in quantities enough to produce explosive or ignitable mixtures. (See NEC Article 500, NEC Article505,API RP 500, and API RP 505.)
Class I,Division 1 location: A Class l,Division 1 location is a location: l) in which ignitableconcentrations of flammable gases or vapors exist continuously,intermittently,or periodically undernormal operating conditions; or 2) in which ignitable concentration of such gases or vapors may existfrequently because of repair or maintenance operations or because of leakage; or 3) in which breakdown orfaulty operation of equipment or processes might release ignitable concentrations of flammable gases orvapors, and might also cause simultaneous failure of electrical equipment. (See NEC Article 500 and APIRP 500.)
Class I, Division 2 location: A Class I, Division 2 location is a location: 1) in which volatile flammableliquids or flammable gases are handled, processed, or used, but in which the hazardous liquids, vapors, orgases will normally be confined within closed containers or closed systems from which they can escapeonly if accidental rupture or breakdown of such containers or systems or abnormal operation of equipment occurs; or 2) in which hazardous concentrations of gases or vapors are normally prevented by positivemechanical ventilation,but that might become hazardous through failure or abnormal operation of theventilating equipment; or 3) that is adjacent to a Class I, Division 1 location,and to which hazardousconcentration of gases or vapors might occasionally be communicated unless such communication isprevented by adequate positive-pressure ventilation from a source of clean air, and effective safeguardsagainst ventilation failure are provided.(See NEC Article 500 and API RP 500.)
Class I, Zone 0: A Class I,Zone 0 location is a location 1) in which ignitable concentrations of flammablegases or vapors are present continuously; or 2) in which ignitable concentrations of flammable gases orvapors are present for long periods of time.(See NEC Article 505 and API RP 505.)
Class I, Zone 1: A Class I, Zone 1 location is a location 1) in which ignitable concentrations of flammablegases or vapors are likely to exist under normal operating conditions;or 2) in which ignitableconcentrations of flammable gases or vapors may exist frequently because of repair or maintenanceoperations or because of leakage; or 3) in which equipment is operated, or processes are carried on, of sucha nature that equipment breakdown or faulty operations could result in the release of ignitableconcentrations of flammable gases or vapors and also cause simultaneous failure of electrical equipment ina mode to cause the electrical equipment to become a source of ignition; or 4) that is adjacent to a Class I,Zone 0 location from which ignitable concentrations of vapors could be communicated,unlesscommunication is prevented by adequate positive-pressure ventilation from a source of clean air andeffective safeguards against ventilation failure are provided. (See NECArticle 505 and API RP 505.)
Class I, Zone 2: A Class I,Zone 2 location is a location 1) in which ignitable concentrations of flammablegases or vapors are not likely to occur in normal operation, and if they do occur, will exist only for a shortperiod;or 2) in which volatile flammable liquids,flammable gases,or flammable vapors are handled,processed,or used, but in which the liquids,gases,or vapors normally are confined within closedcontainers or closed systems from which they can escape only as a result of accidental rupture orbreakdown of the containers or system, or as the result of the abnormal operation of the equipment withwhich the liquids or gases are handled, processed, or used;or 3) in which ignitable concentrations offlammable gases or vapors normally are prevented by positive mechanical ventilation,but which maybecome hazardous as the result of failure or abnormal operation of the ventilation equipment; or 4) that isadjacent to a Class I, Zone 1 location,from which ignitable concentrations of flammable gases or vaporscould be communicated, unless such communication is prevented by adequate positive-pressure ventilationfrom a source of clean air,and effective safeguards against ventilation failure are provided.(See NECArticle 505 and API RP 505.)
classified location: A hazardous (classified) location is a location classified as Division 1 or Division 2, orZone 0,Zone 1, or Zone 2.
communication and electronics circuits: Electrical circuits supplying equipment and systems for voice,sound,or data transmission,such as telephone,data communication,interior communication,pagingsystems,wired music systems,fire and general alarm systems,smoke and fire detection systems,closedcircuit television, and microprocessor-based automated alarm and control systems.
double-banked: The arrangement of cables in a cable tray or raceway wherein the cables are stacked intwo layers.

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