Wetlink With Thin Cable (2mm Load Cell)

Load cell with 2mm shielded wire and it needs to go into an enclosure. I’d like to use a wetlink, though the potted penetrators are a fallback.

Wrapping self-amalgamating tape around the 2mm wire is tricky and a bit dodgy.

Does anyone have experience with potting a cable to ‘thicken’ it to a 4mm diameter so it’s compatible with the wetlink line?

Are there any other ways to thicken the wire so it can be gripped by the wetlink?

The wetlinks seem good, but it would be good if there was a kit/box of different grommet sizes for different wires.

  • Depth: 30m operational
  • Not load bearing

Thanks!

Hi @ChrisDLikesROV, welcome to the forum :slight_smile:

That’s not something we’ve tried, but it could potentially be possible by using a 3D-printed mould to ensure a consistent diameter.

Smaller cable sizes have been asked about and discussed previously here, where the suggestion was to use heat-shrink to increase the cable jacket diameter.

It may be worth considering an adhesive-lined heat shrink for waterproofing and avoiding pull-out and push through, but given your non load-bearing use-case and the radial pressure of the WetLink penetrator’s compression seal I don’t expect they would be particularly significant issues.

thanks eliot - yep missed that post in my forum search - confusing title.

i’m sla printing a mould and will try this out, will give an update if it works.

For adhering to a cable/instruments under pressure eg. like potting a cable. Is it better to use flexible resins (eg. silicone/polyeurethane) or hard epoxies?

I’m a little uncertain about what’s going on/what deforms under pressure. My guess is that a hard resin would have a greater pressure rating, limited only by the deformation of the cable jacket. With flexible resins if it’s softer then the cable, then that will deform to allow water to penetrate first?

I don’t have a heap of experience with potting, but I’d assume that rigid potting makes sense where it’s desirable to protect the internals from external pressure, whereas flexible potting likely makes more sense for situations where the potting is expected to deform. By that logic, potting around a device should likely be rigid, while potting a cable should be flexible, to allow the cable to flex (and to avoid stress concentrations at the edge of the potting).

That seems particularly relevant for a compression-gland seal, where the compression plug is expected to compress both the seal and the cable jacket. Rigid epoxy may prevent the seal from being as strong, and could provide a protective shell that holds back the seal pressure and allows water to slide through by compressing the cable jacket underneath the epoxy. That’s purely conjecture though (I don’t have test data or specific experience to back it up), so take it with a grain of salt.