., material, design) may
influence the installation.
Chapter 32: Classification external influences
IEC Publication 721 Classification environmental conditions.
Explanation the codification for external influences Chapter IEC 364-3 (1977):
Each condition external influence designed code comprising group two capital
letters and number follows:
The first letter relates the general category external influence:
A environment
B utilization
C construction buildings
The second letter relates the nature the external influence:
A .. Table 8..
Chapter IEC 364-3 establishes the classification external influences which require
assessment the design and erection electrical installations.g..
B ..g.. Therefore IEC
has issued relevant standards for classification external influences and environmental
conditions, e.1 shows list of
external influences.
. EXTERNAL INFLUENCES EFFECTING ELECTRICAL EQUIPMENT
AND INSTALLATION
Electrical equipment and electrical installations are exposed external influences, not only
during their use, but also during transportation, storage, and erection.
Note: This classification not intended used for marking equipment.EXTERNAL INFLUENCES EFFECTING ELECTRICAL EQUIPMENT AND INSTALLATION
76
8.
For example the code AC2 signifies:
A environment
AC environment-altitude
AC2 environment-altitude 2000 m.
C ..
3 .
All these external influences may hamper the safety electrical installations..
Part Assessment general characteristics.;
but also utilization equipment the construction buildings (e.....:
IEC Publication 364-3 (1977) Electrical installations buildings.
The number relates the class within each external influence:
1 . Such external influences
may be: ambient temperature, humidity, altitude, water, mechanical stresses, flora, fauna, etc.
2
