Chapter Three - Installation
59
Definitions
The following Class and Division explanations are derived from Article 500
(Sections 5 and 6) of the United States National Fire Protection Agency National
Electric Code (NFPA 70, 1990). They are not complete and are included here only
for a general description for those not familiar with generic hazardous locations'
requirements.
Persons responsible for the installation of this equipment in Hazardous Locations are
responsible for ensuring that all relevant codes and regulations related to location
rating, enclosure, and wiring are met.
Class I Locations
Class I locations are those in which flammable gases or vapors are or may be present
in the air in quantities sufficient to produce explosive or ignitable mixtures.
Class II Locations
Class II locations are those that are, or may become, hazardous because of the
presence of combustible dust.
Division 1 Locations
A Division 1 location is one in which flammable or ignitable gasses, vapors, or
combustible dusts and particles can exist due the following conditions:
• Normal operating conditions.
• Because of repair, maintenance conditions, leakage, or where mechanical failure or
abnormal operation of machinery or equipment might release or cause explosive or
ignitable mixtures to be released or produced.
• Combustible dusts of an electrically conductive nature may be present in hazardous
quantities.
Note
Xycom Automation systems are not suitable for installation within Division 1
locations.
Note
Electrical equipment cannot be installed in Division 1 locations unless they are
intrinsically safe, installed inside approved explosion-proof enclosures, or installed
inside approved purged and pressurized enclosures.
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