Garage wiring - advice

[msheppard36]

Hi, looking for some advice.

I have a garage with existing wiring from my consumer unit to the garage. A single 2.5mm T&E to a fused light switch and a single socket. Last year I built a summer house and installed the cabling for 2 double sockets and a pendant light switch. I ran 4mm armoured cable underground (20m long) and into my garage where it stops. I now need to get everything connected. I intend to replace the cable from the house to the garage. I intend to add 1 double socket in the garage at the same time, one of which will run a tumble dryer and the other a freezer. Id like to know...

1. What size of cable should I use going into the garage? (its about 4 m from the consumer unit). The summerhouse will not be supplying anything that will need a lot of power.
2. Will I need an RCD protected new consumer unit in the garage for my summerhouse supply and garage supply?
3. Anything else you might advise.

Much appreciated.

 

[motorbiking]

Does your consumer unit have an RCD? If you intend to keep your FCU "fused light switch" (I assume it has a 13A fuse), then 2.5mm is fine, however I'd personally suggest a new radial for the garage or garden room on a 16A MCB (or both) as it will give you a bit more flexibility.

 

[msheppard36]

The existing consumer unit in the house is not RCD protected. At some point I intend to replace this too.

 

[Taylortwocities]

That 4mm to the summer house needs to originate from the consumer unit. That way the existing garage circuit can remain as it is.
This work (and your thoughts of a replacement consumer unit) is all notifiable work.

Is your garage attached to the house?

 

[msheppard36]

Yes, its not integrated but it is attached. The existing cable comes straight from the consumer unit through into the garage. It is on its own circuit. The problem I have, given your comment, is that the 4mm SWA cable stops within the garage. It is not long enough to connect to the consumer unit in the house.

 

[deadshort]

I would extend it and allocate a circuit on the new CCU for the summer house. As TTC has suggested, it makes for a nice tidy job, and allows you to isolate each building if required. You may want to run a seperate circuit for the Freezer at the same time.

DS

 

[msheppard36]

Ok, thanks for the replies. I will extend the SWA cable and take it through to the CU in the house. As the SWA cable terminates in the garage currently, I assume I could take it to a junction box in the garage and then use PVC cable to the consumer unit inside the house?

 

[Taylortwocities]

Yes. A length of 4mm T&E, or larger will do it.
You'll need to use an appropriate box to terminate the SWA. You'll be using a proper SWA gland to provide earthing for the armour, or course!

You'll need to show the local authority bod all of this as part of your notification process.
Oh woops - you should already have raised a building notice before you started work..