A rubber knockout grommet provides a specified interface at a panel opening. For cable routing, it helps reduce contact between the cable jacket and the cut edge.
Match the knockout dimensions, panel thickness and cable passage. Check the retaining profile and follow the installation instructions. A grommet should not be assumed to provide rated electrical insulation, strain relief or an enclosure seal unless documented for those functions.
Choose the compound for the operating temperature and exposure. For a nonstandard opening, provide a drawing or existing sample for manufacturing review. Verify fit and the relevant performance requirements before production use.
