Dehumidifying Dry Cabinets – Discover More..
Outdoors, or in wet indoor environments like wash-down areas, Dry Storage Cabinets of electronic systems start out with the appearance of the enclosures and penetrations, and end with the design and configuration of the components. This short article concentrates on a number of these best practices.
Assume your enclosure will leak. Unless the application form demands a vented enclosure (e.g., for heat dissipation, battery off-gassing), a sealed enclosure represents the initial line of defense against moisture. Unfortunately, even the best NEMA 4 electrical enclosure is effective until poor installation practices or out-year modifications create poorly sealed penetrations (Fig. 1).
It’s advisable to assume that penetrations into any enclosure will leak (as shown by Fig. 2). Based upon this assumption, top-mounted conduit penetrations where moisture can collect on horizontal surfaces needs to be avoided. Even if Myers hubs or sealing locknuts are employed for code compliance, enclosure penetrations should be made below energized parts, if at all possible.
In terms of cable penetrations (versus conduit penetrations), directing water from the electrical enclosure or housing through the use of drip loops (Fig. 3) is an additional best practice. The next step is to heat-shrink the connector fittings and alternate wrappings of electrical tape and butyl self-adhesive rubber tape to guard against moisture intrusion into the connector.
Maintaining door seals is essential. Door seals needs to be inspected to make sure panel doors are sealing properly by observing surface wear on the seals. Larger doors with few latches are particularly problematic as flexing from the door may prevent a uniform seal. And finally, seals needs to be inspected for pinching, tears and proper adhesion to original mating surfaces.
Assume all conduits contain moisture
The next best practice for Dry Cabinets For PCB Storage of electronics assumes that even in the event the conduit penetrations are perfectly sealed, the conduits are still planning to contain moisture. Underground conduit often is left unsealed during construction (allowing moisture accumulation), and conduit runs can potentially have multiple points where moisture can enter. Conduit with Moisture Control Cabinets can transfer water vapor right into a sealed enclosure. Typically, when electronics are energized, heat is generated and also the air in the enclosure can hold even more moisture than ambient conditions, meaning water vapor is less of a problem. The problem happens when the enclosure temperature drops (as a result of equipment being de-energized, cooler nighttime temperatures, cooler weather conditions, etc.) as well as the temperature inside xakleh enclosure drops beneath the dew point, resulting in condensation.
Expanding polyurethane foam sealant (Fig. 4) provides an excellent approach to sealing around conduit cabling: It’s been found to be better than silicone, primarily because caulking guns used with silicone are difficult to insert far enough in to the conduit to accomplish a powerful seal. A growing foam nozzle attachment can be inserted further into the conduit to generate a powerful seal across the cabling.