Gasket Sealing
The elastomer gasket between the cover and the housing is the part that actually carries the declared IP protection. A code such as IP67 is the laboratory result for a new product; once the gasket has hardened and been permanently crushed, the enclosure no longer provides that same code. Sealing is a question of material life.
The gasket closes the surface gaps by being crushed to a certain degree when the cover screws are tightened. As long as this compression stays elastic the gasket recovers after every opening and closing. Thermal cycling, UV and contact with oil/solvents harden the elastomer; the gasket takes a permanent set and micro channels stay open even when the cover is closed.
- Symptom: traces of moisture inside the housing, dust build-up at the cover edge, the gasket not springing back when pressed with a finger, or a network of cracks on its surface.
- Application mistake: taking the gasket out of its groove and seating it wrongly, trapping a cable or a label at the cover edge, lubricating the gasket with a non-silicone oil instead of grease.
- Correct practice: at every opening wipe the gasket and its seating surface with a clean cloth, and if damaged replace it with a new one of the same cross-section.
The outdoor receiver of the SF200 and ST200 sets comes with a gasketed cover. Every intervention that opens and closes the cover in the field leaves re-establishing the seal to you.
The context in which this term is used: Complete guide to IP protection ratings