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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
  • Helios, a spur without fuse and 2.5mm cable may feed either one double or one single socket, from the 18th edition. Your situation may be incorrect in that dishwashers usually have smaller heaters than 3kW, often 1.5 kW. 4.5 kW will usually blow a 13A BS1362 fuse in a few minutes as you have observed. There is no need to have the FSU at all, then you have no problem with anything and the circuit is compliant, and very unlikely to suffer from overheating as the cable will take at least 1/2 an hour to get to 70C, by which time the water in both appliances will be ata operating temperature. Please buy at least an Onsite Guide, and preferably take the 18th edition exam if you are professionally engaged in electrics.


    Kind regards

    David
Reply
  • Helios, a spur without fuse and 2.5mm cable may feed either one double or one single socket, from the 18th edition. Your situation may be incorrect in that dishwashers usually have smaller heaters than 3kW, often 1.5 kW. 4.5 kW will usually blow a 13A BS1362 fuse in a few minutes as you have observed. There is no need to have the FSU at all, then you have no problem with anything and the circuit is compliant, and very unlikely to suffer from overheating as the cable will take at least 1/2 an hour to get to 70C, by which time the water in both appliances will be ata operating temperature. Please buy at least an Onsite Guide, and preferably take the 18th edition exam if you are professionally engaged in electrics.


    Kind regards

    David
Children
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