RCBOs and Clipsal Box

[TheScullster]

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

[John Rumm]

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.

[TheScullster]

"John Rumm" wrote

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

[John Rumm]

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.

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).

[<me9]

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.

[John Rumm]

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

[thescullster]

"John Rumm"wrote

Thanks for comprehensive response John Much appreciated

Phil