A (long) note on Ethernet connector weather protection, or lack of it

Ben Stein

Ben Stein

Publisher of Panbo.com, passionate marine electronics enthusiast, 100-ton USCG master.

17 Responses

  1. Ted Arisaka Ted Arisaka says:

    Nice writeup Ben. I also prefer the gland type connection offered by the Ubiquiti Bullet setup. But for the other unprotected RJ45 connections, would a dab of dielectric grease have helped stave off the corrosion?

    • Ben Stein Ben Stein says:


      Dielectric grease would probably have helped the pins themselves some but the reality is the RJ-45 Cat5e coupler included isn’t water resistant at all so I suspect the main thing dielectric grease would have done is move the corrosion to another point in the coupler. There’s a good chance that would have been somewhere harder to see.

  2. Ben Ellison Ben Ellison says:

    Sorry for your pain, Ben, but I’m also wondering about what happens with the Shakespeare WebWatch when you screw it into a 1-inch mount? Unless I’m misunderstanding something you will either have to do this with all the cables unrun and bundled so they can turn too, or by turning the mount itself and fastening it to the boat afterwards. Otherwise won’t the cables get twisted and possibly damaged?

  3. Besides using a nice beefy gland that’ll pass an RJ45 connector, the Bullet uses power-over-ethernet. That means there only cable passing through the gland is the ethernet cable, making it much, much easier to achieve a watertight seal. As soon as you pass more than once cable through an opening you compromise its ability to keep the water out. The only way I’ve been able to (sort of) solve it is to embed the bundle in butyl tape where it passes through the gland.

  4. Joe Hersey says:

    Out of curiosity, I looked up IEC 61162-450 standard for ethernet used on maritime radio communications and navigation equipment, and saw they require connectors and cables meet IEC’s maritime environmental standard for protected equipment, e.g. “Four periods of seven days at 40 °C with 90 % – 95 % relative humidity after 2 h salt spray”. For exposed environments they recommend M12-type.

  5. Antti N says:

    At work (industrial automation) we only use M12 connectors for mechanical strength and corrosion resistance. Connectors are relatively cheap, I wonder why anyone would use anything else when there is salt water nearby. Best quality brand is Phoenix Contact, even using those for every connector onboard you are still only talking relatively low expense, it is only so many connectors after all.

    Problem of course is device fixed connectors, but for a cable end it is easy to change a M12 connector, they are available both in male and female.

  6. Steve Haines says:

    Ben, I’m wondering what sort of ethernet cable you’d recommend for onboard cabling? I have been looking for a stranded (for flexibility) external grade (for water and uv resistance) cable, but cannot find anything. Seems like its either or.

  7. Ben Stein Ben Stein says:


    I believe the outdoor graded cable is significantly more important than stranded versus solid conductors. While I do believe in larger wires stranded is very important the small size of the individual solid conductors in Cat5/6 make it less critical in my opinion. Additionally, solid conductors give a better surface for the pins to be crimped down and against. Another mitigation against potential fatigue of the conductor is to support the cable well, especially at the point of any connections.

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