Electronics used in outdoor or industrial environments must withstand demanding conditions: moisture, dust, temperature fluctuations and mechanical stress are part of everyday operation. Modern enclosures are therefore engineered to be robust, sealed, durable and reliable. However, it is precisely this tight sealing that introduces an often overlooked challenge: the formation of condensation inside the enclosure.
Condensation is not a design flaw, but a natural physical phenomenon. It occurs whenever warm, moisture-laden air comes into contact with a colder surface. As the air cools below the so-called dew point, it can no longer retain all the moisture it carries—resulting in the formation of tiny water droplets.
A familiar example is fogged-up windows in winter: warm air inside meets the cold glass surface, causing moisture to condense. The same principle applies within sealed enclosures, where similar conditions can lead to condensation forming inside the housing.
Even enclosures that appear perfectly sealed cannot completely prevent moisture ingress. This is due to fluctuating environmental conditions:
Temperature fluctuations cause pressure differences between the interior of the enclosure and the surrounding environment
This causes moist air to be literally ‘sucked’ into the housing
As the air cools, this moisture condenses on colder components
In addition, there are other factors such as:
Leaks at cable glands or control elements
Residual moisture that was trapped during installation or maintenance
The consequences can be serious: corrosion, malfunctions and a shorter service life for the electronics.
The IP protection rating indicates how effectively an enclosure is protected against the ingress of solid foreign objects and water. It serves as an important guideline when selecting a suitable enclosure.
However, it is important to note that protection ratings are based on standardised test conditions—specifically without any customer-specific modifications such as drill holes, cut-outs or retrofitted components. In practice, these alterations can significantly influence the level of protection achieved.
In addition, factors such as material ageing and dynamic environmental conditions are not considered within the standard. For this reason, it is strongly recommended to test the fully assembled end device under real operating conditions and, where necessary, obtain appropriate certification.
Suitable OKW enclosure series with high protection ratings for demanding outdoor applications can be found in our blog article on industrial enclosures:
For safe use even in adverse conditions
Effective protection against moisture depends on several factors that should be taken into account as early as the design phase:
1. Materials and construction
Materials with low thermal conductivity reduce rapid temperature changes inside the enclosure and thus also the tendency for condensation to form.
2. Well-designed sealing
High-quality seals are essential, but should always be considered in conjunction with the overall design.
3. Controlled ventilation
A gentle, controlled exchange of air prevents moist air from becoming ‘trapped’ inside the enclosure.
4. Suitable installation location
A dry, well-ventilated installation site can also significantly reduce the risk.
Pressure equalisation elements are a particularly effective solution. They ensure controlled air exchange and equalise pressure differences without allowing moisture or dirt to enter the enclosure.
Modern versions feature special membranes that:
are water- and dust-tight
are oil-repellent
simultaneously allow a high air flow rate
This prevents condensation from forming inside and damaging sensitive electronics.
Important: The proper function of these elements is only ensured if they are correctly installed and remain free from contamination.
Pressure-balancing element with a particularly high air flow rate
Cable glands with an integrated pressure equalisation function offer a particularly practical solution. They combine several advantages:
secure cable entry with strain relief
high protection rating IP68
additional pressure equalisation to reduce condensation
This makes them ideal for applications with limited installation space or where multiple functions need to be integrated in a compact design.
Cable glands with integrated pressure equalisation
👉 Conclusion:
Condensation in sealed enclosures cannot be completely prevented – but it can certainly be controlled. The key lies in the combination of material selection, design, sealing and intelligent ventilation. By opting for well-designed solutions such as pressure equalisation elements or suitable cable glands right from the planning stage, you can provide long-term protection for your electronics and increase the reliability of your equipment – even under demanding conditions.