Double bank dual RCD Board

[JohnD]

My consumer unit is similar to this:
View attachment 283734

This is what I mean by RCBO’s across the two rows.

How should the busbar provide a continuous link between these two rows and ultimately back to the main switch?

I had something similar.

There was a Main Switch, which fed a RCD on the same row, and had two fixed, solid copper, insulated links to the RCD in the other row.


I called it a double-decker.

I have some photos somewhere.

 

[JohnD]

 

[Jupiter01]

Is you problem perhaps that one (probably both) of the rows is currently powered 'through an RCD' in that row (i.e. that row effectively has an 'RCD incomer') whereas, for all RCBOs, you want both rows to be powered by a direct connection to their busbars?

Yes, I think that's the case.

Unless I am barking up the wrong tree, currently, I have 3 busbars:
1. from main switch to 3 RCBOs on top row
2. from RCD #1 to a few MCBs on top row
3. from RCD2 to all MCBs on bottom row

If I want to go all RCBO on top and bottom rows, I need a continuous connectivity to the Main Switch. I could have two busbars and a cable joining them together via MS or something along those lines but wanted to understand if there was a best practice for this.

 

[Jupiter01]

A direct connection unit is required, as shown at the lower right in this product example: https://www.electrium.co.uk/products/product?ProductId=16330
which takes a single wire in the top, and connects to the busbar at the bottom.

Not clear whether Wylex have that available as a separate product.

Sorry, I can't see what you are referring me to. That link takes me to an image of the CU. I can't see the internals.

 

[EFLImpudence]

Unless I am barking up the wrong tree, currently, I have 3 busbars:
1. from main switch to 3 RCBOs on top row
2. from RCD #1 to a few MCBs on top row
3. from RCD2 to all MCBs on bottom row

So, despite my misunderstanding, my replies are nevertheless still valid in relation to 1 and 2 - and possibly even to 3.

In other words the obvious.

If I want to go all RCBO on top and bottom rows, I need a continuous connectivity to the Main Switch. I could have two busbars and a cable joining them together via MS or something along those lines

Of course.

but wanted to understand if there was a best practice for this.

There isn't.

 

[JohnW2]

Sorry, I can't see what you are referring me to. That link takes me to an image of the CU. I can't see the internals.

You don't need to see the internals. I presume that flameport was referring to the item I have highlighted here - a 'straight-through' connector to the L busbar of the lower row - so analogous to a single-pole main-switch which is 'always on'.

Kind Regards, John

 

[JohnW2]

but wanted to understand if there was a best practice for this.

There isn't.

I would imagine that many would say that the sort of approach flameport mentioned, and which I illustrated in the previous post, would (when available for the board in question) be the 'best practice', wouldn't they?

Kind Regards, John

 

[EFLImpudence]

I would imagine that many would say that the sort of approach flameport mentioned, and which I illustrated in the previous post, would (when available for the board in question) be the 'best practice', wouldn't it?

I don't see why that would be the case if there are other ways of achieving the same.

 

[JohnW2]

I don't see why that would be the case if there are other ways of achieving the same.

Well, yes, their might be "joint best" practices - but I think it would be rather odd (and probably an indictment of the manufacturer) if the product provided by the manufacturer specifically for this purpose was not one of them, wouldn't it?

Kind Regards, John

 

[EFLImpudence]

Maybe.

Do you think the usual way of connecting two RCCBs to the Main Switch in a CU - i.e. -

could be described as a 'best practice'?

 

[EFLImpudence]

P.s. I don't see how there can be "joint best" practices.

 

[Jupiter01]

Sorry guys, can you please help me take stock of these suggestions:
- I don't have the type of CU that @flameport has suggested and wasn't planning to replace the one that I have
- This means that I need to have continuous live from the MS to busbars on both rows. Is this best achieved by using a busbar connected from MS, across to all RCBO's on the top row?
I could then take a wire from the MS into the first RCBO on the second row and have a busbar running from this to all other RCBO's on this row.

Is that what is being suggested?

 

[JohnW2]

P.s. I don't see how there can be "joint best" practices.

I don't see why not. In virtually any situation of an 'ordered list', there is always the possibility that there will be two or more 'tied' for the top place.

You may just be quibbling about the semantics of the word "best". If that's the case, what word would you prefer for those which are tied for the top place in a list. Say curry houses are scored for 'how good they are' on a 100 point scale and three score 97 (and none higher) - if you are unhappy with saying that the three were regarded as "joint best", what alternative wording would you suggest?

Kind Regards, John

 

[JohnW2]

- I don't have the type of CU that @flameport has suggested and wasn't planning to replace the one that I have

That doesn't necessarily preclude the possibility that ther is a product designed sepcifically to do what you want (connect an incoming caonduictor to the L busbar of the lower row) with whatever CU you have.

- This means that I need to have continuous live from the MS to busbars on both rows. Is this best achieved by using a busbar connected from MS, across to all RCBO's on the top row?

There surely is no ('nice') alternative to that for the top row, is there?

I could then take a wire from the MS into the first RCBO on the second row and have a busbar running from this to all other RCBO's on this row.

I would imagine that is what most people would do - which is not materially different from how the second RCD is often fed in (single row) dual-RCD board. Products such as flameport has mentioned are designed to avoid having to but a cable, as well as the busbar lug, into one terminal of a device - but, as I've just said, that is something which is very often done - even with 'factory-installed' connections.

Kind Regards, John

 

[Jupiter01]

That doesn't necessarily preclude the possibility that ther is a product designed sepcifically to do what you want (connect an incoming caonduictor to the L busbar of the lower row) with whatever CU you have.

Very interested to hear if anyone knows of a product that can be retrofitted into an existing Wylex CU.

There surely is no ('nice') alternative to that for the top row, is there?

I thought so too

I would imagine that is what most people would do - which is not materially different from how the second RCD is often fed in (single row) dual-RCD board.

I agree. Which type and size of cable should I use for this purpose?

Thanks for your help.