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Total load capacity of twin 13 amp socket ?

broadgage
What is it ?

I understood that twin 13 amp sockets are designed for a total load of 20 amps, and that the approval test is done with 14 amps one one side and 6 amps on the other side.


However recent posts on these fora and elsewhere have stated or implied that the maximum permitted load is only 13 amps in total.


So which is it ?


I appreciate that these sockets are marked "13 amps" on the back, but feel that this MAY be a red herring. The marking MAY mean "intended for 13 amp plugs" rather than "maximum total load 13 amps"


MK brand metalclad twin 13 amp sockets USED to exceed the minimum standard and be suited for a total of 26 amps, is this still the case ?
  • 0
    I have previously been put in my place here by GK, the pair is rated at 13 A.


    That said, we have had washing machine and tumble drier plugged into one double socket and kettle and toaster into another for 20-odd years. Not always one load of clothes out and another in whilst the first are dried; but every breakfast time the bread is toasted whilst the kettle is on. No harm done! ?


    IMHO, the bottom line is that Joe Public would rightly expect to put 13 A in both sides.
  • 0
    Chris Pearson:


    IMHO, the bottom line is that Joe Public would rightly expect to put 13 A in both sides.


    More importantly, there is no way to stop them doing so - and there is no overload protection.


  • 0
    A sustained 26 amp load is very unlikely as apart from kettles, very few modern domestic appliances use more than about 10 amps.

    A total 20 amp load is quite likely, a tumble dryer and a space heater for example.


    Kettles are sometimes a full 13 amps, but seem fine in practice due to the short term use.
  • 0
    Chris Pearson:

    I have previously been put in my place here by GK, the pair is rated at 13 A.


    That said, we have had washing machine and tumble drier plugged into one double socket and kettle and toaster into another for 20-odd years. Not always one load of clothes out and another in whilst the first are dried; but every breakfast time the bread is toasted whilst the kettle is on. No harm done! ?


    IMHO, the bottom line is that Joe Public would rightly expect to put 13 A in both sides.


    These days, even manufacturers who said "13 A per outlet" in their literature now say "13 A" full stop. There may well always have been some confusion between whether "socket-outlet" referred to a single or double version, and we still call a double socket-outlet a single "point".


    Certainly, the temperature rise test now is no different than it was back in 1984, perhaps even earlier ... but it's worth noting that the temperature rise test has a maximum duration of 8 hours, so it is not really intended to simulate repeated overload of the accessory, just a one-off occurrence lasting a single typical "working day"


  • 0
    broadgage:

    A sustained 26 amp load is very unlikely as apart from kettles, very few modern domestic appliances use more than about 10 amps.

    A total 20 amp load is quite likely, a tumble dryer and a space heater for example.


    Kettles are sometimes a full 13 amps, but seem fine in practice due to the short term use.

     


    How many minutes does a domestic kettle take to boil water?


    Z.


  • 0
    13 Amp double sockets can burn out and fail for many reasons. One reason is poor quality manufacture. A second reason is poor contact between 13 Amp plug pins and socket contacts. Another reason (but less likely these days) is a poorly installed 13 Amp plug by an amateur where the flex is not terminated properly.


    Many electrical parts that used to be made of brass or copper in wiring accessories are now made of steel which is presumably electroplated to resemble brass. An example of this is modern Henley blocks. This is good for strength where a gorilla is tightening the grub screws but what does it do for long term  electrical continuity? Perhaps modern double 13 Amp sockets are made of lower quality metals.


    Some flexes that I come across are attracted by a magnet, so are not pure copper.


    Build quality is slipping I am afraid. And just what sort of quality do you expect of a socket that costs less than £2.00?


    Z.


  • 0
    I understood that twin 13 amp sockets are designed for a total load of 20 amps, and that the approval test is done with 14 amps one one side and 6 amps on the other side.


    However recent posts on these fora and elsewhere have stated or implied that the maximum permitted load is only 13 amps in total.


    So which is it ?

    i don't see why both can't be true - it's not unusual for tests to be somewhat in excess of nominal rating in order to allow a decent margin of error/safety. IIRC lifting gear has to pass a test of at least 2x its stated capacity.


       - Andy.
  • 0
    Bad plug burnout of socket..

    Overheated Plug and Damaged Socket Outlet - YouTube


    So, keep your terminal screws tight and your plug pins bright.


    Z.
  • 0
    AJJewsbury:
    I understood that twin 13 amp sockets are designed for a total load of 20 amps, and that the approval test is done with 14 amps one one side and 6 amps on the other side.


    However recent posts on these fora and elsewhere have stated or implied that the maximum permitted load is only 13 amps in total.


    So which is it ?

    i don't see why both can't be true - it's not unusual for tests to be somewhat in excess of nominal rating in order to allow a decent margin of error/safety. IIRC lifting gear has to pass a test of at least 2x its stated capacity.


       - Andy.


    Just as a socket-outlet has a temperature rise test, so does the plug


    In the test for a double socket-outlet, one of the plugs is not sufficiently loaded to achieve what could (in a fully loaded plug) be 37 K temperature rise at the plug pins - but the other is.


    Quite simply, reliance on the product standard alone, in its present form, can't demonstrate that the double socket-outlet is suitable for 2 no. plugs each pulling 13 A.


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