
Enclosure Pressure, Humidity & Condensation

If an enclosure is not protected from moisture penetration, condensation can accumulate on the components inside the enclosure. Outdoor enclosures can be the most vulnerable to condensation, because they are often installed in environments that have high ambient humidity levels. Condensation can cause damage to electrical components, as well as to the enclosures themselves. Some potential hazards include: corrosion, short circuits, premature breakdown, mold and water drainage issues. Installing devices such as heaters, fans, air conditioners and dehumidifiers can help to manage an enclosure’s internal temperatures. These devices are typically regulated by thermostats and hygrostats, which automatically trigger the fans and heaters when ambient conditions reach a certain temperature or humidity level.
Hazardous Location Breather Enclosure Drains prevent moisture build-up within hazardous location enclosures while maintaining the UL Type rating. Drains are to be used when an enclosure is subject to fluctuations in temperature which can lead to the formation of condensation and a subsequent moisture build-up. These drains allow air within an enclosure to breathe with the surrounding atmosphere, preventing condensation and any potential damage to electrical equipment.
Enclosure pressure compensation are devices that provide slow pressure equalization in tightly sealed enclosures that result from heat generated by electrical equipment within the enclosure and fluctuations of outside ambient temperature.
Enclosure hygrostats are devices that control the operation of a heater, turning it on when a preset relative humidity is exceeded inside of an enclosure.
Enclosure dehumidifiers protect electrical equipment within an enclosure by removing moisture from the air caused by condensation.
Enclosure pressure purging is a protection method used to remove any internal explosive dust or gases through a purging process, followed by a pressurization of the enclosure with a protective air or inert gas. This results in a positive internal pressure which keeps any external explosive dust or gases from entering the enclosure.
Products
3 common reasons to use purge systems
- They allow electrical enclosures to be installed in hazardous areas without the need for explosion proof enclosures.
- They recycle the air inside of an enclosure, reducing the internal temperature.
- They help reduce the effects of corrosion on components housed within the enclosure.
How does a purge system work?
Purge systems use incoming air from a supply line, solenoid valves, pressure gauges and pumps, to constantly maintain a positive pressure inside an enclosure. This prevents any flammable gases from entering the enclosure potentially causing an ignition event to occur. By maintaining a positive pressure within the enclosure, moisture and corrosive gases are also prevented from entering the enclosure and damaging components. Most purge systems will ensure that the air inside the enclosure is recycled a certain amount of times within a given time period. This air recycle function assists in maintaining a cooler temperature within the enclosure.