UK Garage consumer unit

[Freyaboo]

Hi can I install a small consumer unit in my garden out house on a SWA cable and connect it directly onto the new consmer unit in the house

 

[Baddegg]

Yep, assuming you have a spare way, you’d also want to correct configuration ie selectively of rcds/rcbos etc.....what sort of loading are you planning in the outhouse?.....any extraneous parts etc? If using the additional protection at the house consumer you’ll need to make sure the new total loading doesn’t exceed the rcd max....

 

[buzzlightyear]

New feed part p it.

 

[pc1966]

As above!

If it is not critical (i.e. just lights and occasional 13A socket use) so you can live with poor selectivity then feeding it from a MCB in your CU is OK. Ideally you don't want it on any home RCD circuits due to the additional inconvenience and time locate any fault out there, and most "garage CU" come with a 30mA RCD and a couple of MCBs anyway.

If you have plans for a workshop, hot tub, etc, then you would be better splitting your tails and feeding it from a fused switch. Push the upstream fuse as high as your cable end's Zs will allow for meeting 5s disconnection, and try to keep the downstream MCBs to around half of that if you need good selectivity. The downstream MCBs can provide the overload protection for the SWA cable.

If you really worry about big faults, try to keep your fused-switch below around 60% of the DNO fuse rating!

Look at your load/use-case and start juggling the numbers...

 

[Spoon]

Just to add to the above, adding a small consumer unit to your garage falls under Part P and you will need to notify your local authority. This will cost money.