Pressure compensation elements
For enclosures without compensation, the interaction of temperatures with the influence of water and moisture will result in moisture being sucked into the enclosure through the seal. This means that IP protection is no longer guaranteed! In order to compensate for these variations in pressure which are caused by differences in temperature, it is absolutely necessary to fit a pressure compensation element (DAE).
This video shows what happens when no pressure compensation element is fitted in spite of variations in temperatures:
Note: Of course, this is only a test setup for demonstration purposes. In a real-life outdoor situation, water is not sucked in via a hose – it is “breathed in” or absorbed via the seal in the course of many cycles.