Honeywell RMA 3000, Руководство пользователя

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Release 1 34-ST-25-19 RMA 3000 Remote Meter Assemblies User Manual 33
6/04
Appendix C - Hazardous Locations Reference
Reference Information
Information is provided to clarify the Hazardous Location installation requirements in
North America and internationally. An explanation of the applicable enclosure
classification systems is also provided
.
North American Classification of Hazardous Locations
Electrical Codes
Installation of electrical apparatus within hazardous (classified) locations of the
United States is conducted under the provisions of the National Electrical Code
(NEC), ANSI/NFPA 70, Article 500; and within Canada, under the provisions of the
Canadian Electrical Code (CEC) C22.1, Part 1, Section 18.
Classifications
In both the United States and Canada, hazardous locations are classified into one of
these three classes
.
Class Description of Hazardous Location
I Presence of flammable gases or vapors may be present in quantities
sufficient to produce explosive or ignitable mixtures.
II Presence of combustible dusts, powders or grains.
III Presence of easily ignitable fibers or flyings.
Divisions
The classes listed above are further classified into one of the following divisions
based upon the level of risk present.
Division Description of Risk
1 Locations in which hazardous concentrations of flammable gases or
vapors, or combustible dust in suspension are continuously,
intermittently or periodically present under normal operating conditions.
2 Locations in which flammable gases or vapors are present, but normally
confined within closed containers or systems from which they can
escape only under abnormal or fault conditions. Combustible dusts are
not normally in suspension nor likely to be thrown into suspension.
Examples
Given the above criteria, the following examples are made:
•
A Class III, Division 1 location is a location in which easily ignitable fibers or
material processing combustible flyings are handled, manufactured or used.
•
A Class III, Division 2 location is a location in which easily ignitable fibers are
stored or handled.