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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
  • Sparkingchip:
    gkenyon:



    BS 5733 if memory serves for the 20 A DP switch.

     




    The Low Voltage Directive 2006/95/EC

    BS EN 60669-1:1999 + A1:2002 + A2:2008

    Modified ISO 22196


    Therein lies the “problem” with 20 amp double pole switches being used in kitchens to switch sockets and appliances, that snow the fact that a lot of the “installation managers” working for the big shed kitchen companies like MFI attended 16th Edition Wiring Regulations courses and were awarded the C&G, so they could “inspect” the electrical work completed by kitchen fitters.


    These “electrical inspectors” would point out the requirements of 537 Isolation and switching and in particular Table 537.4 which states that the 20 amp switches don’t provide isolation, unlike 13 amp SFCU.


    That has set the standard for kitchen fitters and kitchen installations for the last twenty years with an insistence that SFCU should be used above work surfaces to control appliances and inaccessible sockets, because you can take the fuse out of them.


    Generally that’s fine, until someone uses a SFCU to control a double socket.


     Andy B.




    The switch is OK to remove power and provide control. The appliance plug and socket-outlet can provide isolation for maintenance.


    If BS EN 60669-1 is good enough for a cooker switch, which requires a "proper" means of isolation such as the circuit protective device, then it's good enough for an under-counter appliance connected via plug and socket-outlet.


    Or the world has gone mad.


    The user will not remove the fuse and lock off the appliance overnight, so the switch on the FCU does nothing different. The purpose of providing the above counter switch - removing power for fire safety reasons and emergency switching - is still achieved by providing a switch to BS EN 60669-1 instead of an SFCU ...


Reply
  • Sparkingchip:
    gkenyon:



    BS 5733 if memory serves for the 20 A DP switch.

     




    The Low Voltage Directive 2006/95/EC

    BS EN 60669-1:1999 + A1:2002 + A2:2008

    Modified ISO 22196


    Therein lies the “problem” with 20 amp double pole switches being used in kitchens to switch sockets and appliances, that snow the fact that a lot of the “installation managers” working for the big shed kitchen companies like MFI attended 16th Edition Wiring Regulations courses and were awarded the C&G, so they could “inspect” the electrical work completed by kitchen fitters.


    These “electrical inspectors” would point out the requirements of 537 Isolation and switching and in particular Table 537.4 which states that the 20 amp switches don’t provide isolation, unlike 13 amp SFCU.


    That has set the standard for kitchen fitters and kitchen installations for the last twenty years with an insistence that SFCU should be used above work surfaces to control appliances and inaccessible sockets, because you can take the fuse out of them.


    Generally that’s fine, until someone uses a SFCU to control a double socket.


     Andy B.




    The switch is OK to remove power and provide control. The appliance plug and socket-outlet can provide isolation for maintenance.


    If BS EN 60669-1 is good enough for a cooker switch, which requires a "proper" means of isolation such as the circuit protective device, then it's good enough for an under-counter appliance connected via plug and socket-outlet.


    Or the world has gone mad.


    The user will not remove the fuse and lock off the appliance overnight, so the switch on the FCU does nothing different. The purpose of providing the above counter switch - removing power for fire safety reasons and emergency switching - is still achieved by providing a switch to BS EN 60669-1 instead of an SFCU ...


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