TV shock

Discussion in 'Electricians' Talk' started by PaulTanton, Feb 16, 2011.

  1. PaulTanton

    PaulTanton New Member

    Got a call from a guy saying he got a shock off a TV aerial lead. I went round and found that the exposed metal on the TV was sitting at 56 - 60 volts. Tried the other TV and it?s ok.  I know it?s a fault on the TV but has anyone else ever seen this?
    The coax plugs into a three way splitter 1 from the aerial, 1 to the dodgy TV and 1 to the good TV. When all plugged together, 0 volts. So I think the good TV is holding the screen of the coax at 0 volts.
     
  2. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Can happen if it uses a booster or masthead amplifier(12v).


    Mr. HandyAndy - Really
     
  3. midnight cowboy

    midnight cowboy New Member

    Yes! it's possible that the aerial socket might have been replaced at one time, and a non isolated socket has been fitted.

    Or the faulty TV has at one time been subjected to water ingress running down the co-ax, which over time can  short out the isolating capacitors in the socket.
     
  4. joinerjohn1

    joinerjohn1 Screwfix Select

    When I lived with the ex wife, I used to get a shock off the NTL set top box lead that went to the tv. Not a big shock, but enough to make your arm tingle a bit.
     
  5. Paul, it's not uncommon. I've had the same - I think it was my previous set, a CRT Pannie TV and VCR.

    I can't remeber what the situation was exactly, only that I was realigning the aerial in t'loft and got a tingle from the cable (no amplifier used). Everything worked otherwise as expected.

    Worth contacting the TV manufacturer for their opinions?
     
  6. Dale76uk

    Dale76uk Guest

    Surely, the exposed metal is connected to earth via the CPC??? :eek:
     
  7. joinerjohn1

    joinerjohn1 Screwfix Select

    As far as I'm aware, old television sets didn't have an earth wire attached to the chassis. ;)
     
  8. Dale76uk

    Dale76uk Guest

    Yes, some older televisions were double insulated so there was no requirement to earth them.  But from the OP the chassis is metal so it should have a CPC.  Have you checked the earthing arrangements in the property? perhaps no earth in place??  That would make more sense to have 50v+ on the chassis.
     
  9. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    TVs DO NOT have an earth wire.


    Mr. HandyAndy - Really
     
  10. joinerjohn1

    joinerjohn1 Screwfix Select

    Thanks for the backing there Handy. I knew they never had an earth. Was something to do with the high voltage produced inside the sets. You certainly wouldn't have wanted tens of thousands of volts going through any earthing system of any property ( a time before we all had rcd's etc fitted)
     
  11. PaulTanton

    PaulTanton New Member

    The TV is Class 2, ie no earth. It's still in warrenty so Mr Client has taken it back to the shop.
    Thanks for the comments.
     
  12. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    They'll probably tell him it's normal.


    Mr. HandyAndy - Really
     
  13. brumelec

    brumelec New Member

    well my Samsung 55" Plasma 3D TV has an earth
     
  14. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    And a computer connection!!!!


    Mr. HandyAndy - Really
     
  15. J.P.

    J.P. New Member

    Dunno about TV's and stuff..but some amps respond well to lets just say..''grounding''
     
  16. J.P.

    J.P. New Member

    Yes agree HA..have felt tingles before on aerial connections..it makes you wonder if the PD is dragged from the central core onto the coax braid, and if this is the case would it be beneficial to drag the braid down to earth..;)
     
  17. joinerjohn1

    joinerjohn1 Screwfix Select

    Dunno about the PD being dragged to the coax braid, JP, but I wish it wouldn't. ;)

    PS, my dad is a professional entertainer and on his set up, he doesn't connect the earths to every bit of equipment he has. Apparently it can cause an "earth loop" which causes hum through the speakers. I've tried telling him to sing instead of humming, but he pays no attention to me. ;)
     
  18. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    I'm not too sure, but with some amplifying stuff, an earth can act as a sort of aerial, which causes hum.

    In other cases(as in old machines), it was essential to connect to earth to STOP the hum. Strange stuff, sound.


    Mr. HandyAndy - Really
     
  19. joinerjohn1

    joinerjohn1 Screwfix Select

    Well Handy, my dad has an echo unit, microphones, guitar and keyboards all plugged into one amplifier. Apparently it does work ( I have seen and heard the results for myself) Perhaps some electrician or nuclear scientist, would care to elucidate further on why this should be??
     

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