10mm T&E to 6mm T&E

[farqu01]

Hi

I have recently had a bathroom replaced which had an electric shower, this was changed out for a mixer shower off the combi boiler.

The shower cable is a 10mm twin and earth which was pulled back to loft space and JB'd.
A 40amp cb fed the shower.

I am wondering if it is ok run a 6mm supply to my garage, tying into the above JB with the 10mm cable?

There will be a garage consumer unit installed which has a 40amp 30ma rcd, 32amp and 6amp cbs fitted.

The 10mm cable appears to be a horrendous,tight run hense reason asking if ok to utilise jb for supply.

Thanks

 

[Lister1987]

Hi

I have recently had a bathroom replaced which had an electric shower, this was changed out for a mixer shower off the combi boiler.

The shower cable is a 10mm twin and earth which was pulled back to loft space and JB'd.
A 40amp cb fed the shower.

I am wondering if it is ok run a 6mm supply to my garage, tying into the above JB with the 10mm cable?

There will be a garage consumer unit installed which has a 40amp 30ma rcd, 32amp and 6amp cbs fitted.

The 10mm cable appears to be a horrendous,tight run hense reason asking if ok to utilise jb for supply.

Thanks

The obvious question; What would you be looking to run with it, load wise?

 

[cliffed]

shame you can’t just continue in 10mm,but understand,no problems in changing cable to 6mm.
Mcb should be 32 amp for protection .

 

[farqu01]

The obvious question; What would you be looking to run with it, load wise?

Just lights and 3 or 4 double sockets.
Nothing pulling extensive load, need power points for general use such as hoover, karcher power washer, general every day houshold garage.
Reason I mention 6mm is that I happen to have a drum of this so if ok to use rather than purchasing 10mm cable.

Thank you

 

[ipf]

As previous, the 40 amp breaker is too big for 6mm.
Also, it would need RCD protection. It seems to be lacking, as you're intending the garage unit to have one.
Suggest you get someone qualified.

 

[telectrix]

if the 6mm is ref. method C, then a 40A breaker is OK.

 

[farqu01]

As previous, the 40 amp breaker is too big for 6mm.
Also, it would need RCD protection. It seems to be lacking, as you're intending the garage unit to have one.
Suggest you get someone qualified.

The 40 amp breaker is on the RCD side of the house consumer unit.
Going by other posts, Ill jist run in the 6mm from house CU to garage and get a 32amp breaker fitted in house cu.

 

[Dustydazzler]

In reality the chances of overloading a 6mm cable with a small garage installation is slim to none. A neat joint up in the loft via an adapter box with glands would be neat and tidy. Cable clipped above any loft insulation Would be best.
I would happily use the existing 40a for this job as long as it’s rcd protected then just put a 2 way garage consumers unit.

 

[farqu01]

shame you can’t just continue in 10mm,but understand,no problems in changing cable to 6mm.
Mcb should be 32 amp for protection .

So if I change the breaker to 32amp I could then tie the 6mm cable into the jb with the 10mm cable?
The 10mm cable breaker us on the rcd side of the house cu.

 

[GBDamo]

As previous, the 40 amp breaker is too big for 6mm.
Also, it would need RCD protection. It seems to be lacking, as you're intending the garage unit to have one.
Suggest you get someone qualified.

Not sure if I've understood you right here.

40A fine if clipped direct and why the RCD, surely the circuit now becomes a distribution not a final and RCD protection should be provide in the garage CU and the 10mm/40A should be moved to the non-RCD side.

Of course all depends on garage location, cable length, type and route.