Ingress Ratings Sold as Marketing against a Real Test Report
Verify ingress claims using ISO IEC 17025 accredited test reports detailing pre and post electrical insulation checks rather than marketing datasheets.
Capillary Water Ingress
Fluid Transport
Moisture movement through narrow channels within an enclosure seal threatens the longevity of electrical assemblies. Capillary water ingress occurs when surface tension draws liquid into microscopic gaps or cracks, bypassing primary barriers. The process depends on the contact angle of the liquid, the channel width, and the material surface energy.
This phenomenon stops when the gap size exceeds the capillary limit or the surface becomes highly hydrophobic.
Driving Mechanic
Fluid draws itself into joint lines and damaged gaskets through the natural pressure generated by surface tension. In microscale openings, capillary water ingress can pull moisture into sealed sensor housings even in the absence of external pressure. This action overcomes standard gravitational forces and can bridge large internal distances within the enclosure.
Design tolerances must remain tight to prevent the formation of these hazardous channels.
Material Resistance
Surface treatments modify the contact angle between the liquid and the substrate to alter the drawing force. When a surface resists wetting, capillary water ingress is halted because the liquid forms a high contact angle that prevents natural draw. Utilizing hydrophobic coatings or low-surface-energy polymers minimizes the capillary action.
This approach is verified during design through droplet angle testing.
Verification Method
High-resolution vacuum decay testing determines if microscopic passages exist that would permit moisture migration. Standard differential pressure checks find these leaks. This confirms the seal integrity.