RCBO in place of MCB in garage CU?

[jayc]

I recently moved into a new house and in the garge there is a 2 way CU for the lights and sockets.

I have a 20A MCB for the sockets however I'd like to up the 20A MCB to 32A seeing as I have a small comprssor and other tools in the garage so I thought I'd replace with a 32A RCBO as that would negate the need for the plug in RCD box I have for my lawn mower.

The garage is 5M from the house and is fed from a 6mm SWA feed back the the house CU. All te sockets are wired with 2.5mm cable.

So can I safely up to 32A and will a RCBO then cover all the sockets in the garage?

 

[Taylortwocities]

It sounds like the sockets in the garage are wired as a radial rather than a ring (?)
That is why there is a 20A MCB there as its the max that a single bit of 2.5mm cable can carry. You would need to change the radial to a ring before u can up the fuse rating to 32A.

And why an RCBO? The garage fuseboard should have its own RCD already, or the 6mm could be connected to the RCD side of your main consumer unit.

 

[luminaire]

Is your garage wiring connected directly to the CU in the house?

Or is it connected via an existing socket off the ring main?

If it's the latter then you wont be able to upgrade it.

 

[sm1thson]

You would need to change the radial to a ring before u can up the fuse rating to 32A

otherwise this (or worse) happens

 

[Taylortwocities]

Mr Luminaire, are u a bright spark? The OP already said

The garage is 5M from the house and is fed from a 6mm SWA feed back the the house CU.

 

[jayc]

Hi,

The sockets in the garage are in a ring, ie they don't terminate at the last outlet they return to the CU.

I'm open to suggestions on the RCBO. The garage CU just has a 20 MCB and the house CU doesn't have any RCDs so as far as I can tell there is no RCD proctection at all.

Can I get a combined RCD/MCD to go in my garage CU? Its a wylex unit.

Thanks for the help people

 

[Taylortwocities]

U can get them everywhere, like:
http://cirrus.tlc-direct.co.uk/Products/WYNSBS32slash2.html


Your CU really should have RCD protecting sockets but maybe it was installed prior to that requirement being a regulation.


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[jayc]

Ouch £35! Oh well you can't put a price on safety.

Will this be a simple swap? I think I read that RCBOs use both the live and neutral to detect fault and as such shouldn't share the neutral with non RCD protected circuits so they need a seperate bus bar or am I just confusing myself?

 

[Adam_151]

RCBO has a neutral flylead that you connect to the neutral bar, you then connect the circuit neutral to a terminal on top of the RCBO (next to the phase)

There is also often an extra white functional earth for some filters that help to reduce nuisense tripping