Definitions; Class I Locations; Class Ii Locations; Division 1 Locations - Xycom 9462 System Manual

When in hazardous locations, turn off power before replacing or wiring
modules.
Dans les situations hasardees, couper la courant avant de remplacer ou
de cabler les modules.
To maintain a safe condition, do not use an external keyboard or mouse
when the unit is operating in a hazardous environment.

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 de-
scription for those not familiar with generic hazardous locations' requirements.
Persons responsible for the installation of this equipment in Hazardous Locations are re-
sponsible 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 combus-
tible 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.
Warning - Explosion Hazard
Advertissement Risque D' Explosion
Warning
Chapter 3 – Installation
3-31