The Standards IEC 60947-1, EN 60947-1, “Low-voltage switchgear
and controlgear: General rules”, define the normal operating
conditions for electrical and electronic devices. Such standards
are generally applicable to devices operating within the voltage
limit of up to 1,000 V for alternated current or 1,500 V for
direct current, unless otherwise required by the specific product
standard.
Ambient
temperature
Maximum
temperature: +40 °C with average temperature during 24 hours
not exceeding +35 °C; lower temperature limit: -5 °C.
Altitude
Up
to 2,000 m a.s.l.
Atmospheric
conditions
- Humidity
Relative
humidity not exceeding 50% with temperature of
+40 °C. A higher relative humidity is allowed
with a lower temperature; for example, 90% with
+20 °C (see drawing).
|
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| Level
of environmental pollution |
|
The
following levels of pollution are considered for electrical
and electronic devices:
-
level
1 : there
is no pollution or there may be dry non-conductive pollution;
-
level
2 : normally
the devices can be used in the presence of non-conductive
polluting substances; occasionally there may be temporary
conductivity caused by condensation;
-
level
3 : presence
of conductive pollution or dry non-conductive pollution,
which become conductive with condensation;
-
level
4 :the
pollution causes persistent and high conductivity; such
pollution is caused for example by conductive dust, rain
or snow.
