Hi all

I have a Clisal box with Hager MCBs.
The box is split with power circuits on a single RCD.
To meet 17th edition and satisfy BCO, it looks like I will need RCBOs on
kitchen circuits (lighting and cooker).
Does anyone know whether there are restrictions on what boxes can take the
RCBOs as a retro fit?

TIA

Phil

TheScullster wrote:
Hi all

I have a Clisal box with Hager MCBs.
The box is split with power circuits on a single RCD.
To meet 17th edition and satisfy BCO, it looks like I will need RCBOs on
kitchen circuits (lighting and cooker).
Does anyone know whether there are restrictions on what boxes can take the
RCBOs as a retro fit?

They will generally all be able to take the double width RCBOs. Only the
taller ones will take the single module ones.

That does suppose that you can still get any spares that fit. A good
number are interchangeable, although technically speaking mixing brands
would void the type approval.

--
Cheers,

John.

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"John Rumm" wrote

They will generally all be able to take the double width RCBOs. Only the
taller ones will take the single module ones.

That does suppose that you can still get any spares that fit. A good
number are interchangeable, although technically speaking mixing brands
would void the type approval.

Thanks John - can you clarify please
I can't afford to lose breakers, so double width ones are non-starter.
How do I know whether my box is a "taller one"

Not sure what you mean about voiding type approval.
What difference does the manufacturer of each individual MCB or RCBO make?

TIA

Phil

TheScullster wrote:
"John Rumm" wrote
They will generally all be able to take the double width RCBOs. Only the
taller ones will take the single module ones.

That does suppose that you can still get any spares that fit. A good
number are interchangeable, although technically speaking mixing brands
would void the type approval.

Thanks John - can you clarify please
I can't afford to lose breakers, so double width ones are non-starter.
How do I know whether my box is a "taller one"

Measure the distance from the top of the din rail to any obstructions
above - say the neutral or earth bus bars. Then have a look at the specs
for the RCBO. As long as you have enough space for the device and a bit
to keep the wiring clear of other things then you are ok. (assuming your
CU does not have an unusual busbar like the old Wylex NN types.

Not sure what you mean about voiding type approval.
What difference does the manufacturer of each individual MCB or RCBO make?

In reality probably none. However a manufacturer will design and test
their CU with their matching MCBs / RCDs etc. If you substitute another
then there is no longer any proof that the whole thing will perform as
expected. Personally it would not worry me since there is not much
difference between modern CUs that is likely to make a difference and
all the components are tested to their own individual standards as well.

(My Contactum CUs have MK type S incommer RCDs (TT system), and a Hager
cartridge fuse carrier for the garage submain feed).

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

wrote:
On 23 Jan,
John Rumm wrote:

Not sure what you mean about voiding type approval.
What difference does the manufacturer of each individual MCB or RCBO make?
In reality probably none. However a manufacturer will design and test
their CU with their matching MCBs / RCDs etc. If you substitute another
then there is no longer any proof that the whole thing will perform as
expected. Personally it would not worry me since there is not much
difference between modern CUs that is likely to make a difference and
all the components are tested to their own individual standards as well.

(My Contactum CUs have MK type S incommer RCDs (TT system), and a Hager
cartridge fuse carrier for the garage submain feed).

I've found some types where there is incompatibility with the bus bar entry
position. This can be got round if in the end positions by using a cable
jumper instead of busbar. Whatever this does for type approval is another
matter.

Some you may need a slight double bend in the finger on the bus bar to
get it lined up correctly.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm"wrote


Measure the distance from the top of the din rail to any obstructions
above - say the neutral or earth bus bars. Then have a look at the specs
snip.....

Thanks for comprehensive response John
Much appreciated

Phil