Homebuilt ROVs Forum

Hi all,
Does anyone have an idea on how watertight the actual housing around a cat5/6 cable may be? I imagine there are varying degrees of quality, but I'm wondering whether the cable casing/housing is actually waterproof, and whether it becomes permeable at certain depths.

Cheers

mg

I have used Cat5 cable to 30 meter (100 feet) with no problems.

I have found it to be waterproof in all my tests to but even if water got into the main jacket, you can still strip and epoxy the wires in the waterproof cable penetrator (as shown in the sealing exit wires in the how to section: http://www.homebuiltrovs.com/howtosealingwireexits.html)

Don't rely on cat 5 cable to be watertight. The jacket is super easy to make a small cut in. It wont take much of a hole for a leak.

If using cat5 for switching or low-speed data only (ie not Ethernet or cameras) then electrically, keeping water away from the copper is generally the only concern. So if the outer jacket gets a hole in it, you still have the inner insulation. Just make sure water doesn't get in where the wires have been stripped - refer ROVenthusiast post above.

For video and Ethernet, the loose jacket with air inside is that way for a reason. Distance will suffer should water get in or to a lesser degree pressure compress the jacket

Treat cat5 as cheap and expendable when used as ROV tether. Will last longer with careful handling and for switching applications will still work for a while (until it corrodes) even if full of water. Security alarm or similar multicore cable has a better jacket and nicer to work with but is dearer and not good for video and Ethernet

How much does the security cable cost? I purchased 120ft of cat5 @ Home Depot in bulk for about $35

One thing to be more careful with when it comes to "cheap" cat5 cable is the type of wire that it is made up of. If you plan on moving around a lot and getting lots of dives out of your ROV, you may run into the issue of you wires breaking inside your cat5 tether.

standard "cheap" cat5 cable is made up of solid core wire. if you bend it to many times, the wires inside the cable can break. It takes quite a bit for this to happen, but at key points, it is more likely, such as the connection to your ROV or the connection to your top side controls.

I bought some of the "heavy duty" cable. Hopefully it is of better quality!

It is meant for outdoor use and it says it is "weatherproof". It, I hope, will work out in strength and waterproofness!

I was looking at different cat 5 and some of the stuff made for direct burial has a gel inside between pairs also some has shielding but I didn't come across any that had strand wire rather than solid. I was thinking the gel inside would really help with the waterproof part but also might need more help to make float.

What is every body else using?