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Northernboater's avatar
Northernboater
Joining in
6 months ago
Solved

FTTP coax filter suddenly live 110v AC....tingly!!!

So, I have FTTP, hub3.0

Usual filter between the wall plate and the router(modem in my case!).  Got bit of a zap from it today whilst moving some stuff around. 

Multimeter shows the filter body as 110v to earth. 

Tested the outside of the F connector at the power supply that feeds the wall plate, also 110v to earth, also giving mild shocks. 

I've tested all my other kit, all fine. How do I get a new power supply without 17 hours of explaining it via virgin media chat?

  • goslow's avatar
    goslow
    6 months ago

    Where/how/between what are you measuring the 110V ac?

    • Northernboater's avatar
      Northernboater
      Joining in
      6 months ago

      Yeah it is one of those. Not sure why they decided to use coax for a 500ma 12vdc power supply in the first place - could have been run from the main router power supply which is 2.5a 12vdc. 

      Anyway, back to the problem. Surely VM can just put one in the post? Or upgrade me to a new hub?

      • Roger_Gooner's avatar
        Roger_Gooner
        Alessandro Volta
        6 months ago

        It's coax because it goes into the internal termination box which also contains the coax from the ONT, so it's a clean all-coax installation.

  • goslow's avatar
    goslow
    Alessandro Volta
    6 months ago

    Seemingly not available to post AFAIK (one past topic on here went on for 2 weeks while the customer tried to get one sent before it was eventually established a tech visit was required).

    https://community.virginmedia.com/t5/Forum-Archive/ONU-Power-Supply/td-p/5235411

    In any event, you may need a tech visit for the voltage issue.

    Have you done the test(s) to earth when the power supply is turned off (to confirm it is a power supply fault) and that you are not importing the voltage from outside your home somehow and/or you have an isolator problem.

      • Roger_Gooner's avatar
        Roger_Gooner
        Alessandro Volta
        6 months ago

        You have to despair when a FT member doesn't understand that fixing a fault caused by VM is FOC.

    • Northernboater's avatar
      Northernboater
      Joining in
      6 months ago

      So, it's a class 2 supply, so no earth - the pin is plastic. That rules out my earth being juicy - although earth and neutral will be connected together somewhere down the line!

      It's likely just a bit 'leaky' - very low current. I do have other mains DC supplies that show 120vac, but they don't tingle 😉

      • goslow's avatar
        goslow
        Alessandro Volta
        6 months ago

        Where/how/between what are you measuring the 110V ac?

  • Client62's avatar
    Client62
    Alessandro Volta
    6 months ago

    It is not uncommon for SMPS have some level of high impedance a/c mains leak.



    • Northernboater's avatar
      Northernboater
      Joining in
      6 months ago

      Yeah,I think this one has just become a tad too leaky! 

      I guess usually you would never feel it, unless you happened to be also holding onto something earthed. I've got other smps here that show between 50 and 80vac to earth, but those have no tingle to earth what so ever, even with a wet finger!

  • jpeg1's avatar
    jpeg1
    Alessandro Volta
    6 months ago

    There is officially no longer such a thing as an earth wire. It's a protective conductor on a PME - Protective Multiple Earth. 

    The old days of 'earthing' everything to the copper water pipe are over, now that mains water pipes are plastic. 

    • Northernboater's avatar
      Northernboater
      Joining in
      6 months ago

      On a new build maybe. My supply is TN-S, so no PME as such, mine will be PEN- protective earth neutral, aka earth.....

       

      But certainly where either the mains water or gas, or any other service, comes out of the ground and Into your house using a conductor, then equipotential bonding is still needed..... My gas pipe is copper to the meter, and copper into the house, and my mains water is copper to the first valve, hence needs bonding, and it was also build when supplementary bonding was required!

  • jpeg1's avatar
    jpeg1
    Alessandro Volta
    6 months ago

    There's quite a variety of 'earthing' arrangements, according to the age of the building and when it was last rewired.  And the IEE wiring regs are frequently updated too.