I have an application wherein I need a hermetic seal at cable exit points from a plastic housing. The cables are not removable. I'd like to achieve this seal using the plastic housing itself by creating a friction fit between the hole and PVC cable jacket (since there's only about 5mm of vertical space to work with). A couple questions:

  • Is this possible? How can one prevent the seal from breaking as the cable is moved into different positions?

  • What are the best practices for such designs?

Thanks for your help!


The solution you have suggested will not be waterproof for long. The reason is that, if you pull on the cable it will stretch and thin very slightly. This is enough to break the seal.

If you can make the space, a cable gland is the best option.

If you can't, and O-ring seal is probably the next best thing. Make sure to use a thick o-ring with some compression so the seal will be maintained even if the cable stretches slightly.

Another option is to use a rubber "plug" where the cable passes through the center. This can be water tight, but you will have to take great care to make sure the plug is retained and remains under compression with regards to the seal.

You can do a similar thing using potting compound, but it's not trivial. A rigid epoxy will have the same issues as the press fit you have suggested, so you need something semi-flexible. I don't know enough to recommend a product unfortunately.

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  • $\begingroup$ HEYCO CONNECTORS $\endgroup$ – William Hird May 17 '19 at 22:49

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