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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?

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0 Sparkingchip over 4 years ago

This is what happens in the real world, you get a group of people in a certain trade or business that set a way of doing things, that’s not always technically correct or logical, then twenty years later when you question someone who has done things the same way for twenty years as to why they do it that way they either don’t know or can’t remember why, but just know that’s the way it’s done.

Kitchen fitters and electricians have got into the habit of using SFCU above work surfaces in kitchens to control inaccessible sockets rather than 20 amp switches, because “that’s the way it done “.

It all goes back to the kitchen installation managers having done a Wiring Regulations short course twenty years ago and Table 537.4 in BS7671 saying that 20 amp switches don’t provide isolation.

Just to complicate it more they would also point out that table says plug and sockets don’t provide emergency switching, so even if the socket was accessible you still needed the SFCU, as the SFCU fulfils all three requirements of isolation, emergency switching and functional switching.

Old habits die hard!
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0 Sparkingchip over 4 years ago

This is what happens in the real world, you get a group of people in a certain trade or business that set a way of doing things, that’s not always technically correct or logical, then twenty years later when you question someone who has done things the same way for twenty years as to why they do it that way they either don’t know or can’t remember why, but just know that’s the way it’s done.

Kitchen fitters and electricians have got into the habit of using SFCU above work surfaces in kitchens to control inaccessible sockets rather than 20 amp switches, because “that’s the way it done “.

It all goes back to the kitchen installation managers having done a Wiring Regulations short course twenty years ago and Table 537.4 in BS7671 saying that 20 amp switches don’t provide isolation.

Just to complicate it more they would also point out that table says plug and sockets don’t provide emergency switching, so even if the socket was accessible you still needed the SFCU, as the SFCU fulfils all three requirements of isolation, emergency switching and functional switching.

Old habits die hard!
Cancel
Vote Up 0 Vote Down

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Overloaded fused spur, opinion please

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