help with garage wiring back at the house...

[RUBOB1]

Hello all

I am new to all of this and am trying to find out how the experts would solve my problem. I have a detached garage with a garage distribution board with a 40A 30mA RCD and 2 x MCBs (6A & 32A). I have wired this to 10mm 3 core swa with the armour terminating on the outside of the garage in a junction box (I have earted the swa steel with a seperate 10mm bond to the inside garage unit.

My problem is that the primary distribution box is on show in the porch of the house and I would like to keep all the house and garage in a single unit.

The swa terminates at the outside of the porch in a junction box 2 feet down from the internal main distribution board, I can pull cables through the cavity up to the back of the main board.

What rating and type of mcb or switch could I use in the primary unit - I am trying to avoid nuisance rcd tripping at the house rather than at the garage for this circuit. Does it have to be rcd at the house?

Thank you
Bob1

 

[ban-all-sheds]

I have wired this to 10mm 3 core swa with the armour terminating on the outside of the garage in a junction box

Why?

My problem is that the primary distribution box is on show in the porch of the house and I would like to keep all the house and garage in a single unit.

Why?

The swa terminates at the outside of the porch in a junction box 2 feet down from the internal main distribution board,

You are fond of these external junction boxes, aren't you.....

What rating and type of mcb or switch could I use in the primary unit

I find it rather scary that someone who thinks he can install sub-mains and CUs and new final circuits doesn't know the answer to that.

• http://www.tlc-direct.co.uk/Book/6.1.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/6.2.1.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
  
  
• //www.diynot.com/wiki/electrics:part-p
  

- I am trying to avoid nuisance rcd tripping at the house rather than at the garage for this circuit. Does it have to be rcd at the house?

You have already decided that you are qualified to design and construct electrical installations - are you now saying that you don't know what the regulations concerning RCD protection are?

What are you going to do about testing?

 

[PrenticeBoyofDerry]

What rating and type of mcb or switch could I use in the primary unit

I have a detached garage with a garage distribution board with a 40A 30mA RCD and 2 x MCBs (6A & 32A).

The clue here would be the demand of the garage CU.
So 32A or 40A would be suitable.

I have wired this to 10mm 3 core swa with the armour terminating on the outside of the garage in a junction box (I have earted the swa steel with a seperate 10mm bond to the inside garage unit.

Is there a logical reason behind this, why did you not take the cable in to the garage?

My problem is that the primary distribution box is on show in the porch of the house and I would like to keep all the house and garage in a single unit.

That's fair!

The swa terminates at the outside of the porch in a junction box 2 feet down from the internal main distribution board, I can pull cables through the cavity up to the back of the main board.

What rating and type of mcb or switch could I use in the primary unit - I am trying to avoid nuisance rcd tripping at the house rather than at the garage for this circuit. Does it have to be rcd at the house?

This depends on what you do with the remaining two feet of cable between SWA and CU, if you had brought the SWA in to house without joints/junction. It would be possible but now the remainder of this (2 foot) could compromise the requirements.