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mda99das's avatar
mda99das
Up to speed
24 days ago

Electrolysis corrosion of ethernet cable when PoE is used.

I laid 2 ethernet cables 15 plus years ago, which is cat5 e. The section that runs under the grass I passed through hosepipe except for a small section where I had to cut a notch into a semicircular pipe so the grill could slip over it. One of the CCTV cameras is a bit flakey, and it was only under investigation that there appears to be some kind of electrolysis happening. There is blue corrosion , my chemistry is a bit rusty but I do know copper sulphate is blue while oxide is black. I'm trying to figure out the mechanism. I'm sure the voltage being applied set up a magnetic field. The metal pipe I am unsure if it is metal. Some reaction must have occured causing heat and plastic to melt in a damp environment causing a short. I am going to have to relay this ethernet cable and the second cable does have a small perforation so that will go the same way. What can I do to protect this second cable?

13 Replies

  • goslow's avatar
    goslow
    Alessandro Volta

    Did you use external grade cable 15 years ago?

    • Tudor's avatar
      Tudor
      Very Insightful Person

      External Ethernet cable is used because it is treated to not be affected by UV rays. Don’t think it matters when run underground.

  • jpeg1's avatar
    jpeg1
    Alessandro Volta

    But the plastic insulation on ordinary ethernet cable is not designed to be impervious. After many years underground it will let in damp. 

    • goslow's avatar
      goslow
      Alessandro Volta
      jpeg1 wrote:

      But the plastic insulation on ordinary ethernet cable is not designed to be impervious. After many years underground it will let in damp. 

      👍

    • jpeg1's avatar
      jpeg1
      Alessandro Volta

      That's the stuff. You'll need to get suitable connectors to terminate it.

      • mda99das's avatar
        mda99das
        Up to speed

        Wow that stuff looks amazing. To lay it I will have to lift up the patio slabs. Out of interest after watching some leak videos, I had no idea that copper pipes encased in concrete corrode. Some of my ethernet cable is encased in concrete. For now I have made a temp join while I figure out a more permanent solution. However waterproofing is what I am looking at. For the repair I put 2 ethernet female connectors on and linked it with a patch cable . It works this way. Trying to join all 8 wires directly by twisting did not work. I'm thinking of neutal silicone and encasing it  for now. I accept both cables are on last legs.

  • goslow's avatar
    goslow
    Alessandro Volta

    Crimp some plugs onto the ends of your broken cable and use an external coupler such as

    https://www.kenable.co.uk/en/networking/network-accessories/network-plugs-couplers/11262-external-outdoor-cat6-rj45-etherenet-coupler-joiner-waterproof-weatherproof-hood-011262-5021196806202.html

    Or use an internal junction box and find some way of waterproofing it

    https://www.amazon.co.uk/FGB-Junction-Punchdown-Coupler-Ethernet/dp/B0DJVZBPP3

    such as self amalgamating tape.

    https://www.toolstation.com/self-amalgamating-repair-tape/p23876

    Any which way, a broken cable in a drain, with a temporary make-do repair, is not going to last very long.

    Are you using a punchdown tool for your terminations?

    https://www.toolstation.com/heavy-duty-punch-down-tool/p40716

     

    • mda99das's avatar
      mda99das
      Up to speed

      There are some good solutions, it does look like a bit of a bodge job, just been super busy but this weekend I am looking at making it proper. Long term would be to relay 2 x cat 6 cables in hosepipe. I have a punchdown tool, nothing fancy plastic tool with a metal U at the end to push the wire into the connector.

      • goslow's avatar
        goslow
        Alessandro Volta

        Nothing wrong with patching up to get it working again as a temporary measure but don't expect it to last very long.

        If you are going to lay in new cable, armoured cable would be the most robust solution if you are going to lay it in the drain channel again (but also the most expensive). You would need some CW (= external grade) cable glands to terminate the armouring (if there is any risk of moisture at the ends) into boxes where you would fit a Cat 6 faceplate at each end. The armoured cable is weather and waterproof. The steel wire armour protects the cable from mechanical damage/crushing and from being nibbled by rodents.

        Cheaper option is to use external grade Cat 6 (without the SWA) and put the cable inside a conduit of some kind. Hose pipe is not ideal as it is not designed to pull cables through (it will be hard to pull the cables over a long run) and it can be crushed easily. Seek out a corrugated flexible electrical conduit or a duct which is designed to be used outdoors (UV resistant and waterproof). A proper electrical duct will allow the cable to be pulled through more easily. Ideally run the conduit in one continuous pieces to prevent water ingress.

        Ideal Yellow 77 can be used to help pull cables through long runs.

        https://www.toolstation.com/ideal-industries-yellow-77-wire-cable-pulling-lubricant/p67429

        Good trick below to allow you to get a pull string through a long piece of conduit

        https://www.youtube.com/watch?v=ldgF_Q2T19A

        Corrugated flexible cable conduit will resist crushing but won't be rodent-proof.

        Use a proper punch down tool. The plastic ones rarely ever push the cable far enough into the connector to pierce the cable insulation, resulting in unreliable connections. A proper punch down tool will crop the little strands of wire from the connector.

        It is possible to use all sorts of kit to run in an outdoor connection but, if you want it to be reliable and last any length of time (against your outlay of hard-earned cash), you need to use the correct tools and materials.

  • Adduxi's avatar
    Adduxi
    Very Insightful Person

    Yes full repull with proper external grade Cat 6. Just make sure it’s not CCA cable!  The punch down you have will eventually wear out and you might be better with a metal one.