install electricity in garage

[benny1975]

Hi

I am planning on putting electricity into my garage which is attached to the house. Would be grateful if you could check to make sure I havent missed anything.

My plans are:

Take electricity from the house CU on the RCD side via a 32 amp MCB and 6mm T&E cable through the wall (in conduit) to a 5 way Wylex CU with 100A 30ma RCD in the garage.

Then a radial circuit from the garage CU 16A MCB to 3 double sockets, 10 metre run in 2.5mm T&E.

Also a lighting circuit from the garage CU 6A MCB to 2 inside lights and 1 outside light (total about 400watt) again about a 10metre run in 2.5mm cable.

All cable will be run in conduit and the spare ways on the garage CU will be blanked off. Nothing particularly heavy will ever be plugged in although in future might want to put a tumble dryer in the garage.

Does this sound OK?

Many thanks

 

[ricicle]

You shouldn't really have 2 30mA RCDs in the same circuit as it is not guaranteed which one will operate first (or both)
How do you propose to test the wiring and devices when you have completed the install ?

 

[flameport]

You don't need a CU in the garage at all.
2.5 mm cable for lighting is far too large, and will create problems in fitting that size wire into the terminals on the lights

A far cheaper, quicker and better solution would be a 20A MCB in the house CU, with a 2.5mm radial circuit to the socket outlets. Add a 3A FCU for the lighting, which should be done in 1mm cable.

 

[benny1975]

Thanks Folks

Flameport - I was going to use a CU in the garage as this is what others in my street have done, but your method sounds simpler.

Ricicle - I was going to use 2.5mm as I will be buying 25m anyway and thought it would be Ok for the lights. Is the 2 RCds a big issue?, although Flameport's method would avoid this issue.

In terms of testing, to be honest I hadn't considered that side of thigs, but will do, I suspect sparks arent overly keen to check other peoples work?

 

[Stoday]

You'll have a problem stuffing 2.5mm TW&E in conduit. Use conduit wire, which is stranded and more flexible.

 

[ban-all-sheds]

• http://www.tlc-direct.co.uk/Book/6.1.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm

The last one talks about testing.