Каталог Weidmuller: Electronics - Analogue Signal Conditioning

Technical appendix/Glossary
EX basics
Safety in hazardous areas
When operating electrical devices within hazardous areas, you
must comply with the requirements regulating their use in such
zones. Explosive atmospheres may be created from mixtures of
flammable gases, mists, vapours or dusts. If their concentration
is high enough in the surrounding air, any source of ignition or
spark could trigger an explosion. Such explosions can cause
death, serious injuries and significant property damages.
There are basically two strategies for reducing the risk of
explosion. Firstly, no dangerous materials should be released
into the air that could create an explosive atmosphere.
Secondly, there should be no mechanism present that could
create a spark.
Many explosions in the past could have been avoided if only
the international regulation governing the use of equipment in
hazardous areas had been observed.
But what are the most important global regulations
regarding the use of devices in hazardous areas
In North America, the US National Electric Code (NEC) regulations
(Articles 500 to 505 and the Canadian CEC (Canadian
Electrical Code) Articles 18-000, -090, -100, -200 and -300
are all valid.
In Europe, both EU directives ATEX 95 (94/9/EG) and ATEX 137
(1992/92/EC) are relevant. They describe preparation (ATEX 95)
and usage (ATEX 137) for facilities in potential Ex zones.
Throughout the rest of the world, there is a mixture of national
regulations (in Eastern Europe) and international IECEx conformity
declarations (in Asia) that must be followed. In certain
Asian countries, the European ATEX directives have been
accepted and applied.
EX
America
v r
Europe
In other countries
NEC 500 … 504 ATEX 95 + ATEX 137
Class I Class II Class III
Base safety -and health
Division 1: Ex-Ambience
requirements
Division 2: Ex-Ambience in fault cases
Zones
2
1
IECEx-Scheme
Further local requirements
with national variations
NEC 505
Mining (I)
Non Mining (II)
0
Class I
Gas
Zone 0-
American approvals:
i.e. UL 508 Industrial Control Equipment,
UL 1604 and UL 60079-…
Approval bases: protection classes.
CE
• Notification of the
production
• EG-confirmation
• Producer confirmation
(Zone 2)
Product Audit
QM-Audit
IECEx Certificate
of Conformity
W
Use with
Approval bases: QM System, protection classes
A brief overview of regulations used throughout the world and their basic content.
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