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Arcing sound from plug socket switch

Discussion in 'Electrics UK' started by harlow, 30 Sep 2018.

  1. harlow

    harlow

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    I have a double socket in the bedroom and every time I turn the switches off for the tv I can hear a arcing noise from one of the switches so I plan on changing the socket but is it best to use a single or double pole socket and what's the best brand to buy.
     
  2. PrenticeBoyofDerry

    PrenticeBoyofDerry

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    It does not really normally matter whether you use SP (single pole) or DP (double pole). But in theory DP would be safer.
    I use BG or click normally. But MK, Crabtree etc.. are fine.
     
  3. winston1

    winston1

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    TV have their own switches so why are you turning the socket off? But if you must turn off the TV first. A new socket may do the same.
     
  4. harlow

    harlow

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    The tv don't have a switch so I have to put it on standby then turn it off at the socket.
     
  5. ban-all-sheds

    ban-all-sheds

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    Have a look and see how long the cables are behind the socket, and whether there's any slack that can be pulled through. Maybe post a photo.

    Reason being that if they are very short and there is no slack then you might need to make sure you buy a socket with the terminals in the same places as the existing one if you are to be able to connect the wires.
     
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  6. ban-all-sheds

    ban-all-sheds

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    Shouldn't be a problem - socket switches are able to make and break full load current.
     
  7. bernardgreen

    bernardgreen

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    For most makes that is true but only for non-inductive loads.

    From the tech spec for MK plate switches "" Current rating: 20 amps – no derating when used on fluorescent or inductive loads""

    The same "no derating" comment is not applied to MK 13 amp sockets
     
  8. JohnW2

    JohnW2

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    I might, of course, be wrong, but I would be rather surprised if BS1363 allows a switched 13A socket to have a switch which is not able to safely (and without damage) break a highly inductive 13A load. Does anyone know?

    Kind Regards, John
     
  9. ban-all-sheds

    ban-all-sheds

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    upload_2018-9-30_17-11-53.png
    upload_2018-9-30_17-13-0.png
     
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  10. JohnW2

    JohnW2

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    Interesting. Thanks. I suppose the requirement for it to be able to break a "substantially non-inductive" current of 17A, means that it would able to break an "appreciably inductive" (but not necessarily 'highly inductive') one of 13A.
     
  11. ban-all-sheds

    ban-all-sheds

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    Dunno.

    Or an extremely inductive load of a couple of amps? It's a TV power supply remember..
     
  12. JohnW2

    JohnW2

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    Indeed. In any event, I think that most SMPSUs have PF correction these days, so probably not a significantly inductive load at all.
     
  13. winston1

    winston1

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    Why? It will miss all the overnight updates. Modern TVs take negligible power in standby and are meant to be left in standby to receive the updates. Most countries don't have switches on their sockets.
     
  14. bernardgreen

    bernardgreen

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    It is not the magnitude of the current being broken but the magnitude of the stored energy on the inductor when the current is broken and the back EMF created when the nagnetic field is collapsing. The resultant arc between the switch contacts is the main cause of contact wear and premature failure when supplying inductive loads
     
  15. JohnW2

    JohnW2

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    Yes, but that's really just a play on words, since the 'magnitude of stored energy' (stored in magnetic field) is, itself, determined by the magnitude of the current.

    In fact, since that stored energy is given by LI²/2, the fact that it is a function of I², rather than just I, means that the stored energy increases rapidly as current increases.

    Kind Regards, John
     
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