Outdoors, or in wet indoor environments like wash-down areas, Electronic Dry Cabinets of electronic systems start out with the design of the enclosures and penetrations, and end with the design and configuration of the components. This post targets a number of these best practices.
Assume your enclosure will leak. Unless the application form requires a vented enclosure (e.g., for heat dissipation, battery off-gassing), a sealed enclosure represents the first line of defense against moisture. Unfortunately, even the best NEMA 4 electrical enclosure works well until poor installation practices or out-year modifications create poorly sealed penetrations (Fig. 1).
It’s best to think that penetrations into any enclosure are going to leak (as shown by Fig. 2). Based on 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 being used for code compliance, enclosure penetrations needs to be made below energized parts, if possible.
In terms of cable penetrations (versus conduit penetrations), directing water away from the electrical enclosure or housing with the use of drip loops (Fig. 3) is another best practice. The next task is to heat-shrink the connector fittings and alternate wrappings of electrical tape and butyl self-adhesive rubber tape to safeguard against moisture intrusion in to the connector.
Maintaining door seals is incredibly important. 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 of the door may prevent a uniform seal. And lastly, 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 Storage Cabinets For Optics of electronics assumes that even when the conduit penetrations are perfectly sealed, the conduits continue to be 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 Dehumidifying Dry Cabinets can transfer water vapor into a sealed enclosure. Typically, when electronics are energized, heat is generated as well as the air inside the enclosure can hold even more moisture than ambient conditions, meaning water vapor is a lesser problem. The issue happens when the enclosure temperature drops (as a result of equipment being de-energized, cooler nighttime temperatures, cooler climate conditions, etc.) and also the temperature inside xakleh enclosure drops underneath the dew point, leading to condensation.
Expanding polyurethane foam sealant (Fig. 4) gives an excellent approach to sealing around conduit cabling: It’s been found to become superior to silicone, primarily because caulking guns used in combination with silicone are difficult to insert far enough into the conduit to attain a highly effective seal. A growing foam nozzle attachment can be inserted further in to the conduit to produce a highly effective seal round the cabling.