How to Prevent Condensation in Enclosures

If you’ve ever seen dew on the grass in the morning, you’ve seen a phenomenon called condensation. And while it might be picturesque on someone’s lawn, that same phenomenon can wreak havoc on electronic and electrical equipment, even when they’re housed inside electrical enclosures.

Choosing the right enclosure for an electrical or electronic device means accounting for all of the environmental hazards that the device might face. Condensation is one that should never be overlooked since it can allow moisture into an enclosure.

How does the process of condensation work, and what can be done to keep out condensation in an electronics enclosure? We’ll cover these topics in today’s post.

Facts About Condensation

How does condensation work? It all comes back to what’s called phase change: the transition of matter between different states such as liquid and gas. In many environments, particularly outdoor ones, water vapor (a gas) is suspended in the air. This is the phenomenon we know as humidity.

Warm air can accommodate a lot of water vapor, which is part of why humidity is often higher in the summer. The capacity of air to hold water vapor diminishes as the air temperature decreases. This is why you’ll often see a measurement called relative humidity used to quantify humidity as it relates to ambient temperatures — the same amount of water vapor in the air may cause condensation at an air temperature of 45 degrees, but not at 65 degrees. 

Thus, when moist air cools, water begins to condense or return to its liquid state. (This condensation is part of the phenomenon that causes all precipitation such as rain and snow.) If humid air comes into contact with an object with a temperature at or below the dew point, water will begin to condense on the object. Electronics enclosures, particularly ones in an outdoor environment, often fit the bill.

Condensation does little harm when it collects on the outside of an enclosure (although salt water condensation can present a corrosion hazard unless a corrosion-resistant enclosure is used). However, when condensation is allowed to build up inside an enclosure, it’s a recipe for trouble.

How Condensation Can Harm Electrical and Electronic Equipment

Condensation can act as a back door for moisture in an otherwise-dry enclosure. It’s the stealthy invader that strikes where you might not expect it, and it can create big problems for the electronics inside the enclosures.

Outdoor enclosures can be some of the most vulnerable to condensation since they’re often installed in environments that have high humidity levels. If an enclosure isn’t protected from moisture ingress, condensation can accumulate on the components inside the enclosure. In sub-freezing conditions, water that condenses and then freezes becomes frost, which can potentially do even more damage to sensitive device components.

Condensation can cause all kinds of damage to electrical and electronic components, as well as enclosures themselves. Some of the potential hazards associated with condensation inside enclosures include:

• Short circuits
• Corrosion
• Premature breakdown
• Contamination by mold and other organisms
• Water drainage from enclosures
• Risk of shock to employees

All in all, it’s clear that preventing condensation in enclosures will be essential for many enclosure buyers. The next question: How can that be achieved?

How to Prevent Condensation in Electrical Enclosures

Device designers and engineers have developed a toolbox of equipment and techniques to help control condensation in enclosures. Here are some of the most important and commonly used:

• Using a watertight outdoor enclosure, typically at least a NEMA 4 enclosure, NEMA 4X enclosure or NEMA 6 enclosure to protect the device. These enclosure ratings are designed to offer watertight protection, and many include watertight gasket seals made from materials such as food-grade silicone rubber. Polycase offers a full range of outdoor enclosure options.
• Installing devices such as heaters, air conditioners, dehumidifiers and fans inside an enclosure to help manage the enclosure’s internal temperatures. These devices are typically regulated by components such as thermostats and hygrostats, which automatically trigger the heaters’ or fans’ activation when ambient conditions reach a certain level of temperature and/or relative humidity.
• Selecting a vented enclosure (or adding waterproof air vents to an enclosure) to improve the enclosure’s ventilation and airflow. Vent plugs are another popular way to provide airflow with no compromise in condensation protection, thanks to their liquid-tight seals and ultrasonically-welded membranes that keep vapor out.
• Applying corrosion inhibitor sprays or gels to the enclosure and/or its electrical components to prevent the potentially corrosive effects of condensation.
• Add desiccant packets (silica gel packets) inside the enclosure to help absorb moisture.

By staying aware of the dangers that condensation poses and taking steps to mitigate them, you can help make sure that your devices are protected. More questions about how to prevent condensation in enclosures? Our enclosure experts would love to hear from you. Just call us at 1-800-248-1233 or contact us online for a free quote.