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Overloaded fused spur, opinion please

I was an industrial electrician and have now come across a domestic wiring issue where nothing appeared wrong with the installation.  Those with more experience will have probably have come across this many times.


The kitchen is supplied by a 2.5mm T&E ring fed from a B32 circuit breaker.  On this ring there is a 13A fused switched spur above the worktop feeding a double socket underneath via 2.5 T&E.  There is a washing machine and a dishwasher plugged into this double socket.  Every so often, I assume when both appliances are heating at the same time, the 13A fuse in the spur blows.  The cable supplying this double socket is in the wall so the current-carrying capacity appears to be 18.5A so this was probably being overloaded as well.


I understand that in the regs diversity covers some aspects of this situation, but this specific situation must occur often surely?  The switched spur gives the ability to switch off the appliance easily without having to pull it out in order to reach the switch, so is surely desirable?


In this case I have installed a second switched fused spur feeding a single socket and converted the other to a single.


Is this a common problem in kitchens?
Parents
  • As always I am concerned about two flat plates clamping a round conductor (sorry I keep harping on about it).

    I think the point about terminal ampacity is that any number of conductors bunched together in a terminal has many points of contact so providing it is mechanically secure then good ho in my opinionas you are not relying solely in the current carrying capacity of the terminal itself.

    That`s what I liked about the old wylex 604 etc - a round terminal hole and two screws, a sight sphere on the pointy end to cause a slight anchor by dimpling the conductor and of course two such screws increased anchoring and area of contact.


    I know a bloke, he says he has a degree in electrical engineering (I have no reason to doubt him).

    He claims that he was taught that doubling (or twisting) conductors to increase point of contact is not only wrong but "ruf" in his opinion.

    He disagrees with me and his wife`s brother (an electrician) about that.

    To my way of thinking, if in an ideal world, your conductor size and shape matches the terminal size and shape then current transfer between conductors is good.

    I did not like the look of his one strand of 1.0mm2 conductor in an ashley JB20A  on his security lighting (tungsten halogen) and that`s why I mentioned doubling to him and got his ruf comment.

    I am not aware of anyone else agreeing with him
Reply
  • As always I am concerned about two flat plates clamping a round conductor (sorry I keep harping on about it).

    I think the point about terminal ampacity is that any number of conductors bunched together in a terminal has many points of contact so providing it is mechanically secure then good ho in my opinionas you are not relying solely in the current carrying capacity of the terminal itself.

    That`s what I liked about the old wylex 604 etc - a round terminal hole and two screws, a sight sphere on the pointy end to cause a slight anchor by dimpling the conductor and of course two such screws increased anchoring and area of contact.


    I know a bloke, he says he has a degree in electrical engineering (I have no reason to doubt him).

    He claims that he was taught that doubling (or twisting) conductors to increase point of contact is not only wrong but "ruf" in his opinion.

    He disagrees with me and his wife`s brother (an electrician) about that.

    To my way of thinking, if in an ideal world, your conductor size and shape matches the terminal size and shape then current transfer between conductors is good.

    I did not like the look of his one strand of 1.0mm2 conductor in an ashley JB20A  on his security lighting (tungsten halogen) and that`s why I mentioned doubling to him and got his ruf comment.

    I am not aware of anyone else agreeing with him
Children
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