CU as isolator box

[EFLImpudence]

I do not see the need for a bank of switches (grid switches) next to a bank of switches that does the same.

But the point being made is that they do NOT do the same thing.

Drawing out the appliances from the housings is not easy.

True, but when becoming faulty, unavoidable.

Also having a 3 pin plug with 13A fuse is another thing to go wrong - right behind the fixed in appliance.

Well, that's all we have.
They don't have to be behind the appliance if you are rewiring the kitchen.

They can positioned in an adjacent unit and be neatly made accessible.
That's all you need for each appliance to be individually and totally isolated.

Row of white switches above worktops ruin a kitchen

Gold?

 

[flameport]

I am trying to find out the best way, and most cost effective, using the one switch box, the CU box.

If fitting an all RCBO unit, put a second DP switch in it which controls the kitchen circuits only. Total cost £10.

Also having a 3 pin plug with 13A fuse is another thing to go wrong - right behind the fixed in appliance.

If the fuse has blown, there is something wrong with the appliance, meaning you will have to remove it for repairs / replacement anyway.
Not having a plug means you will need an FCU with a fuse in it elsewhere, which will cost more and add further points of failure.

I suppose having the fridge/freezer on a non-RCD circuit is a good idea in case of a trip when on hols.

It's totally unnecessary and achieves nothing.
The most likely causes for RCDs tripping is water leakage, usually outside lights, boilers or immersion heaters. However all of these should be on separate circuits from the kitchen sockets so any trip would not affect the freezer.
Kettles, toasters and irons are also likely causes, but if you are on holiday, they won't be in use to cause trips.
If something goes wrong with the freezer itself, or another unlikely thing such as rats chewing through wires, which would you rather have - a bit of ruined food in a freezer, or your whole house burned to ashes?

 

[Brightonguy]

I do not see the need for a bank of switches (grid switches) next to a bank of switches that does the same.

But the point being made is that they do NOT do the same thing.

They are. The idea to get the same functionality inside the CU.

13A sockets cannot go anywhere expect behind the appliances.

Gold sockets? Very Chavvy. Enough to make me vomit.

 

[JohnW2]

I suppose having the fridge/freezer on a non-RCD circuit is a good idea in case of a trip when on hols.

It's totally unnecessary and achieves nothing. The most likely causes for RCDs tripping is water leakage, usually outside lights, boilers or immersion heaters. However all of these should be on separate circuits from the kitchen sockets so any trip would not affect the freezer.

I presume you mean 'separate RCDs', rather than just 'separate circuits'. If so, that is, of course, by no means always the case.

If something goes wrong with the freezer itself, or another unlikely thing such as rats chewing through wires, which would you rather have - a bit of ruined food in a freezer, or your whole house burned to ashes?

Quite - and it's not even the 'either/or' you're suggesting. If the freezer itself developes a fault, of if rats chewed through its supply (and certainly if that caused the house to burn down), the food would quite probably still be ruined, even in the absence of an RCD on freezer circuit - so the food may well get ruined either way!

Kind Regards, John

 

[Brightonguy]

I am trying to find out the best way, and most cost effective, using the one switch box, the CU box.

If fitting an all RCBO unit, put a second DP switch in it which controls the kitchen circuits only. Total cost £10.

That is one of the option.

I do not want fuses to blow. It want the protection on the CU to trip.

I do not want FCUs at all.

It is possible for one circuit to malfunction and trip the RCD taking out a whole bank of circuits, inc the freezer.

If something goes wrong with the freezer itself, or another unlikely thing such as rats chewing through wires, which would you rather have - a bit of ruined food in a freezer, or your whole house burned to ashes?

That circuit alone could be on the one and only RCBO.

If UK standards were like I have seen in Germany on new homes where the CU was all DP RCBOs on all circuits we would not have theses problems. A CU with all DP RCBOs is still an option.

 

[JohnW2]

That is one of the option. I do not want fuses to blow. It want the protection on the CU to trip. I do not want FCUs at all.

If you don't want fuses in plugs or FCUs, then (a) what size of MCBs/RCBOs are you be proposing for each of the appliance's circuits and (b) how would you propose to connect the appliances to their circuits?

Kind Regards, John

 

[Brightonguy]

That is one of the option. I do not want fuses to blow. It want the protection on the CU to trip. I do not want FCUs at all.

If you don't want fuses in plugs or FCUs, then (a) what size of MCBs/RCBOs are you be proposing for each of the appliance's circuits and (b) how would you propose to connect the appliances to their circuits?

Kind Regards, John

JohnW2, thanks. The MCB's will be sized to suit the appliance - the nearest best fit. One mcb per appliance, so easy enough to do. I have seen a 3-pin plug without a fuse, but I think was an illegal import from India. Are they available? As these types of plugs are not available, appliances would be directly wired using an outlet connection box behind in the housing, as they do on the Continent. A 13A fused plug behind and a fixed appliance in a housing is unnecessary and achieves nothing (apart from huge inconvenience if it blew for no reason, which does happen) as the protection on the CU would come into play.

 

[JohnW2]

If you don't want fuses in plugs or FCUs, then (a) what size of MCBs/RCBOs are you be proposing for each of the appliance's circuits and (b) how would you propose to connect the appliances to their circuits?

JohnW2, thanks. The MCB's will be sized to suit the appliance - the nearest best fit. One mcb per appliance, so easy enough to do.

I see. I guess that will mean 16A in most cases (for ~3kW appliances).

I have seen a 3-pin plug without a fuse, but I think was an illegal import from India. Are they available?

If you're talking about 13A plugs, I can't say whether they are 'available' but, if they were, they (and their import into UK) would be illegal. There are probable 15A round-pin plugs without fuses available.

As these types of plugs are not available, appliances would be directly wired using an outlet connection box behind in the housing, as they do on the Continent. A 13A fused plug behind and a fixed appliance in a housing is unnecessary and achieves nothing (apart from huge inconvenience if it blew for no reason, which does happen) as the protection on the CU would come into play.

As you say, that is the practice on the Continent, but there are potential problems with that approach in the UK. For example, the manufacturer's instructions for the appliances will probably specify protection by a 13A fuse, so (stupid though it may be) reliance on a 16A MCB might well invalidate the appliance's warranty.

Kind Regards, John