connecting rcbo to mcb is it possible?

[nathan grant]

Hi

I'm just about to get my consumer unit upgraded , but my shower is on a rcbo in the garage, which connects to the mcb in the consumer unit. This was installed 6 years ago. The cable was cut short so a rcbo was placed in a box in the garage. Not good practice I know but the bathroom was complete before we realised.
Now is this still ok with the new 17th wiring reg's.

Thanks

nathan

 

[ban-all-sheds]

Why won't you simply get it sorted out as part of the CU upgrade?

 

[ColJack]

The cable was cut short....

it won't reach the location of the new CU..

you can use the "RCD" box as a terminal box and fit terminals on the din rail likely to be inside it.. then add a new piece of cable to the new CU..

 

[nathan grant]

yes that's right the cable wont reach to the consumer unit, but is using the rcd box as a terminal box a better installation practice? Are you saying to then move the rcbo to the consumer unit? If not wouldn't the cable from the terminal box to the consumer unit require to be rated at 80amps. large cable!!!!

thanks

 

[ColJack]

yes put the RCBO into the new CU.. ( or more specifically get a breaker / RCBO put in the CU for the shower as it has to be the same type as the rest of the CU. )

 

[Goldberg]

wouldn't the cable from the terminal box to the consumer unit require to be rated at 80amps.

What shower unit do you have, i.e. what is its power rating at 240V?

 

[Lectrician]

wouldn't the cable from the terminal box to the consumer unit require to be rated at 80amps.

What shower unit do you have, i.e. what is its power rating at 240V?

And is it AC or DC?

 

[nathan grant]

The shower is 9.5kw and the run is about 15 meters max in 10mm cable with a 40amp RCBO.

 

[Goldberg]

The shower is 9.5kw and the run is about 15 meters max in 10mm cable with a 40amp RCBO.

In that case you should use 10mm² from the terminal box to the consumer unit. 6mm², if clipped direct and completely uninsulated, would be adequate, but the cost saving doesn't make up for the confusion that it could cause.

 

[plugwash]

Now is this still ok with the new 17th wiring reg's.

Afaict that would depend on the type of cable used for the section between the CU and the enclosure in the garage and how that cable is installed

 

[slup]

And is it AC or DC?

That made me chuckle...