On a 4" tube setup I have 8 sets of penetrators installed, plus a few SubConn bulkheads. The penetrators are all made with the 16/2 cable and marine epoxy, following the instructions. The 16/2 cable is then connected to a Tsunami 1200GPH bilge pump.
When I do a vacuum seal test to 15-20 inHg there is a slow leak, probably around 1inHg/minute or so. I’m fairly confident that all of the o-ring seals are solid and holding up the vacuum testing, and believe to have issues with air wicking through the wire cores. The connections have been sealed externally with liquid electrical tape and heat shrink that has thermoplastic built in.
Are there any recommendations for trying to find or fix the leaks on this? How likely is it that this setup would be waterproof, but not airtight (the deepest the ROV will go is 40ft for a maximum of 15 minutes)?