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1.6. Protection against rain/snow (precipitation)
The protection rating tests carried out according to IEC
60529 serve as comparative tests and to classify prop-
erties. These tests are limited to a few minutes and can-
not imitate weather through precipitation or cleaning with
a water jet. A general weather test cannot be defined
due to differing local circumstances. For this reason, the
erector requirements of the appropriate installation situ-
ation must always be taken into account.
According to DIN VDE 0100-520, 522.3.1, cable systems
must always be selected in such a way that damage from
condensation or the ingress of water cannot be caused.
This means that condensation water openings should be
available and the junction boxes in outdoor areas may
only be installed with protection.
Installation only in protected external areas
Please note that, in the case of an installation such
as under solar panels, the housings may not be lo-
cated directly under the joints of the solar modules,
or that the housings must additionally be covered
with protective covers.
1.7. Protection against water build-up (frost)
Frequently, with an installation that is not protected
against precipitation, water will collect on surfaces and
in recesses. If these cannot flow away unimpeded, then
this will cause a build-up of water. In the case of low tem-
peratures, this water can freeze and exert an improper
mechanical load on the housing. This can lead to dam-
age to the housings. Therefore, during installation, care
should be taken that the housings are protected by a
cover.
A cover may already exist due to structural circum-
stances, may be erected by the user or be created with
additional components.
Mounting and installation information for junction boxes
1.8. Protection against plants and/or mould growth
The plastics used for electrical installations are organic
materials. For this reason, damage from plants, algae or
mould should be taken into account.
According to DIN VDE 0100-520, 522.9.1, if experience
has shown that plant and/or mould growth can cause
damage, the cable systems must be selected according-
ly or special protective measures must be provided.
Note: A routing type must be selected which allows a
corresponding removal of such growth.
Conclusion:
Taking the above-mentioned parameters into account,
protected installation of the junction boxes is essential
and also described in detail in the erection standards.
Only in this way can safe operation of the protection de-
vices be guaranteed.
Additional information on outdoor installation and
UV resistance:
The information on the protection rating and UV resist-
ance is frequently seen as the only criterion for outdoor
installation. In the case of outdoor installations, other
factors, such as absolute temperature, frequency of tem-
perature changes, humidity and particularly chemical in-
fluences, have a role to play. Besides influences through
UV impacts, with outdoor installations it is damage from
chemical influences, in particular, that are to be expected.
Thus, outdoor areas of petrol stations, chemical plants,
rubbish dumps, compressors, sewage works, etc. must
be investigated particularly critically in advance.
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