1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

2.5mm 16a radial feeding 4.8kw + extractor?

Discussion in 'Electrics UK' started by LiGhTfasT, 27 Mar 2013.

  1. LiGhTfasT

    LiGhTfasT

    Joined:
    27 Mar 2013
    Messages:
    29
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    Hi,

    I'm in the process of planning my new kitchen and seeing what I currently have. On the consumer unit there is a rcd with a 16amp breaker thats labeled kitchen double socket and extractor. Looking at the back of the sockets its fed on 2.5mm cable radial that also then feds an extractor.

    Now for the last 4 years since moving in we've had a 2.7kw tumble drier and 2.1kw washing machine in this socket. By my reckoning thats too much? (both used at same time but never tripped) The socket is around 2 metres from the consumer unit. Maximum i should be using is 3840watt?

    If i get an electrican to make this into a ring and add a few sockets for the new kitchen could this then have a 32amp breaker giving me 7680watt for the new kitchen?

    Thanks
     
  2. Sponsored Links
  3. Sparksense

    Sparksense

    Joined:
    27 Mar 2013
    Messages:
    5
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    4800/230 gives you 20 amp ish that you two machines e on their max output.

    So along as the breaker is rated correctly for the cable you intend to install, and this also meets your load requirements, then yup. Either a 2.5 ring, or a 4mm radial will be suffice for a 32amp breaker in most circumstances.

    Also each appliance should be in its own socket - a lot of double sockets at still only rated at 13amp for the entire socket.

    Your electrician will also need to check for rcd protection, and bonding too.
     
  4. stillp

    stillp

    Joined:
    21 Sep 2009
    Messages:
    4,496
    Thanks Received:
    338
    Location:
    West Midlands
    Country:
    United Kingdom
    If you find any of those then inform Trading Standards, they do not meet the required British Standard, which includes a temperature rise test at 20A.
     
  5. Sparksense

    Sparksense

    Joined:
    27 Mar 2013
    Messages:
    5
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    BS1363-2:1995 requires for double socket outlets that both socket outlets have loads applied via test plugs, 1 test plug having a load of 14 amps whilst the other has a load of 6 amps, making a total load of 20 amps on the cable supplying the double socket outlet. The double socket outlet is then subjected to this loading for a minimum continuous period of 4 hours or longer until stability is reached with a maximum duration of 8 hours (stability being taken as less than 1 degC rise within 1 h). The test is passed if neither the terminals / terminations, nor the accessible external surface, increase in temperature by more than 52 degC.


    They are tested to 20amp total, and my taking is that assume 13amp max per unit, unless manufacturer states 13amp per outlet.
     
  6. stillp

    stillp

    Joined:
    21 Sep 2009
    Messages:
    4,496
    Thanks Received:
    338
    Location:
    West Midlands
    Country:
    United Kingdom
    I agree with the description of the test. Why then do you assume only 13A per unit?
    I would argue that there's a clue in the name "13A socket-outlet". If a manufacturer combines two of them into one unit, that does not stop them being 13A socket-outlets, and therefore having to be suitable for a 13A load.
    My view might be contentious, but I don't see how you could argue that the combined unit is only suitable for 13A total when it has been type-tested to 20A.
     
  7. Sparksense

    Sparksense

    Joined:
    27 Mar 2013
    Messages:
    5
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    The test current is to be larger than operating current under normal loads.

    Similar To a single socket being tested at 14amps, however the test current of 20amp for a double socket is higher due to the consideration that two appliances can be inserted.

    So if the max test current is 20amp, why risk 26amp (2x13) when it has possibly never been tested to this current - though some good manufacturers will.

    That's my take anyway
     
  8. stillp

    stillp

    Joined:
    21 Sep 2009
    Messages:
    4,496
    Thanks Received:
    338
    Location:
    West Midlands
    Country:
    United Kingdom
    Every 13A socket-outlet has to be capable of carrying 13A. Therefore a dual socket-outlet has to be capable of carrying (at least for short periods) 26A.
    Diversity is allowed in the temperature rise test, since in most applications the dual socket-outlet will not be required to provide 26A for anything other than a short period.
     
  9. Sparksense

    Sparksense

    Joined:
    27 Mar 2013
    Messages:
    5
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    If a double socket was designed to take 13amp per socket Outlet - 26amp in total, why do they only test to 20amp?

    However I agree that each point has to be able to support 13amp on its own, but still I believe that the b1363 and th manufacturers mark the unit as capable of 13amp total.
     
  10. Sponsored Links
  11. stillp

    stillp

    Joined:
    21 Sep 2009
    Messages:
    4,496
    Thanks Received:
    338
    Location:
    West Midlands
    Country:
    United Kingdom
    As I've said, they allow diversity in the temperature rise test. Also perhaps when the standard was first written 20A was all that the manufacturers who employed the people who wrote the standards could achieve!

    Most manufacturers seem to be reticent on this subject. I know several who quote 20A total, and some who say nothing, but I've never seen any rating their products at only 13A for a double outlet. The one I'm most familar with ;) has products that can withstand 28A total all day, but they don't want to 'break ranks' and say so in their literature because there is no perceived marketing advantage, and there could be problems in the customers' applications such as plugs melting.
     
  12. bernardgreen

    bernardgreen

    Joined:
    3 Nov 2006
    Messages:
    25,141
    Thanks Received:
    2,489
    Location:
    Bedfordshire
    Country:
    United Kingdom
    The MK twin 13 amp socket in front of me is labelled ( embossed ) as 13 amp 230 volt Not 2 x 13 amp or 20 amp or 26 amp.

    In the past some companies ( the old GPO being one of them ) imposed a limit of 9 amps on 13 amp sockets. Special permission was needed to use them for a higher load and only one or two makes of plug and socket were acceptable for more than 9 amps.

    An old hand ( electrician 1940 to 1980 ) told me that twin sockets came into existance based on the premise that the twin outlet would be considerably neater ( and safer ) than a single socket with a two way adaptor when more and more appliances were being used in homes.
     
  13. stillp

    stillp

    Joined:
    21 Sep 2009
    Messages:
    4,496
    Thanks Received:
    338
    Location:
    West Midlands
    Country:
    United Kingdom
    If you were a manufacturer Bernard, would you emboss any figure other than 13A on the back of your products? Actually I think that the 13A marking is a requirement of the standard, but can't check - I'm in Germany this week. As far as I can remember the MK technical literature states (or used to) the total load as 20A.

    Yes, the GPO downrated everything! The 15A round pin sockets were not to be used beyond 10A, and the 5A ones limited to 3A, if I remember correctly. That's a user specification though.

    I agree with your old hand (not that I'm that old! In the early days of ring finals and 13A plugs, most houses only had one or two socket outlets, and the largest load item was a one-bar electric fire. The iron was usually plugged into a two-way bayonet adator in a light fitting.
     
  14. LiGhTfasT

    LiGhTfasT

    Joined:
    27 Mar 2013
    Messages:
    29
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    well just ordered a 32a siemens breaker and going down the route of turning it into a ring for the kitchen and adding a few more sockets
     
  15. Sparksense

    Sparksense

    Joined:
    27 Mar 2013
    Messages:
    5
    Thanks Received:
    0
    Location:
    Lancashire
    Country:
    United Kingdom
    I think a problem possibly would arise though, if advise was given to customers that you can use the socket for 2 13amp items.

    And possibly due to a defect the socket causes a fire. The manufacturers state 13amp, and so does the bs number. I'm sticking to what I've always done - washing machine and dryer on separate sockets!
     
  16. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,783
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    Is a ring the most appropriate design for that circuit?
     
  17. stillp

    stillp

    Joined:
    21 Sep 2009
    Messages:
    4,496
    Thanks Received:
    338
    Location:
    West Midlands
    Country:
    United Kingdom
    The problem would arise if you advised customers that the dual socket could be used continuously at 13A from each outlet.
    Yes, there could indeed be a problem if said customer used the sockets for items that drew 13A continuously.
    Nothing wrong with using separate (single) sockets - I could start a discussion about the increased number of potential points of failure, but after a couple of Waulanerweissbeers (I did say I was in Germany) I really can't be bothered! :D :D

    EDIT: I meant, of course, Paulaner Weissbeers (which are obviously stronger than I thought!). I'd better sleep it off. 'Night all!
     
Loading...

Share This Page