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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
  • Former Community Member
    0 Former Community Member
    The terminals in a 20A junction box actually carry practically no current, all they do is clamp the conductors together.
    Now to BODs switch, the same consideration as the junction box clearly applies, the terminal carries little or no current, the wires are clamped together, and in some cases twisted too. The terminals do not have a current rating except where they leave the clamp mechanism and become connections to the accessory mechanism. How many wires will fit the terminal has nothing to do with this, in fact the fuller the terminal the higher the current rating will be because of all the touching areas of the conductors.


    Typically MK don't appear to now make their 1132 series in 20 A which I used to like as it was one screw per conductor. Used the brass as a bus bar.

    Perhaps BOD is being BAD BAD again!


    If I were, I'd mention how to do maths using I squared R   !!!!


    Regards


    BOD
Reply
  • Former Community Member
    0 Former Community Member
    The terminals in a 20A junction box actually carry practically no current, all they do is clamp the conductors together.
    Now to BODs switch, the same consideration as the junction box clearly applies, the terminal carries little or no current, the wires are clamped together, and in some cases twisted too. The terminals do not have a current rating except where they leave the clamp mechanism and become connections to the accessory mechanism. How many wires will fit the terminal has nothing to do with this, in fact the fuller the terminal the higher the current rating will be because of all the touching areas of the conductors.


    Typically MK don't appear to now make their 1132 series in 20 A which I used to like as it was one screw per conductor. Used the brass as a bus bar.

    Perhaps BOD is being BAD BAD again!


    If I were, I'd mention how to do maths using I squared R   !!!!


    Regards


    BOD
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