IEEE 303:1991 pdf download.IEEE Recommended Practice for Auxiliary Devices for Motors in Class I,Groups A, B, C, and D, Division 2 ;Locations.
This recommended practice is limited to auxiliary devices associated with motors operating in Division 2 areas. classified as Class I. Groups A, B, C. and D locations. This recommended practice is not an attempt to rewrite or otherwise supersede application sections of ANSI/NFPA 70-1990 111,1 or any other codes or ordinances. Rather, it is intended to serve as a supplement to existing codes that in this area are not sufficiently specific to serve as a guide to good engineering practice. The guidance contained herein, therefore, is in addition to the ANSI/NFPA 70-1990 requirements for wiring systems for hazardous (classified) locations.
2. Purpose
The following information is intended to bring together a brief description of basic electrical practices in regard to the application and installation of auxiliary devices to motors operating in Class I, Groups A, B, C, and D. Division 2 locations It should he understood that this information is only a guide to promote consistent application of such dev ices and must be used with sound engineering judgment.
3. References
This recommended practice shall he used in conjunction with the following publications:
[1] ANSI/NFPA 70-I 990, National Electrical Code.
[2] ANSI/NFPA 496-1989, Purged and Pressurized Enclosures for Electrical Equipment.
[3] ANSI/NFPA 497A-1986, Classification of Class I Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas.
[41 API-RP500-1991 Classification of Locations for Electrical Installations in Petroleum Facilities.3
4. Definitions
auxiliar devices: Components installed either integrally within the motor, located adjacent to or mounted on the motor, or attached to its terminals for the purpose of monitoring the operating conditions or protecting the motor. Refer to 5.2 and 5.3 for examples.
Class I, Division 2 Locations: Basically those in which there may be flammable gas present due to a failure of a process system. Under normal conditions a flammable mixture of gas is not present.
For a complete definition, refer to the latest edition of ANSI/NFPA 70-1990 [1]. Chapter 5, Article 5(X). For a guide in establishing the limits of these locations, refer to API-RP5(X)-1991 [4] and ANSI/NFPA 497A-1986 131.
5. Device Installation Recommendations
5.1 Motor Auxiliary Device Categories
For installation requirements. auxiliary devices generally fall in one of two categories:
1) Devices containing a make or break contact, or both (arcing devices).
2) Devices without a make or break contact, or both (non-arcing devices).IEEE 303 pdf download.