Your views on supplying outbuildings?

[Dave2010]

So if 17th requires every circuit to be RCD protected, and you have a shed at bottom of garden and you take a supply from your CU spare MCB which is protected, does this mean you do not RCD at the shed end?

And do you have to have an earth rod down at the shed instead of connecting to MET in CU?

cheers

 

[Taylortwocities]

So if 17th requires every circuit to be RCD protected,

But the 17th does NOT SAY THAT!

What are your supply characteristics?
Are there services like a water main in your shed?
Is it made of metal?

 

[PrenticeBoyofDerry]

Earth rod depends, the distance of the shed to the main incoming supply is a factor.
If the CU has no RCD protection or the board is a split with half of it protected by an RCD and the other half not, and the MCB is in the non protected side.
It will not be protected,
In these cases an RCBO can be installed.

 

[Taylortwocities]

I would not have the RCD at the house end.
Or have an RCBO for the shed(per Paddy's post above). Otherwise you stand a chance of half the board tripping because the shed got a bit damp.

 

[PrenticeBoyofDerry]

I would not have the RCD at the house end.
Or have an RCBO for the shed(per Paddy's post above) . Otherwise you stand a chance of half the board tripping because the shed got a bit damp.

Depends what cable is being used? This has not yet been mentioned yet!
If SWA is being used as the supply cable to shed, it makes sense to install RCD protection for the circuit within the shed, in the sheds mini CU

 

[properleckie]

Dave2010,
If as you imply your house end mcb is rcd protected then putting a second one in the shed end is unnecessary and the house one will usually trip first anyway as it will already be seeing some leakage current from other circuits, not seen by shed one.
it is recommended to export the house earth to remote buildings unless:
T.T. system.
Metal exposed in shed either building structure or services such as water.
In these cases the SWA cable should be earthed at house end but insulated at shed end and a local rod to create a TT system with an RCD incomer at garage consumer unit.

 

[Taylortwocities]

Dave, you may find this of interest.

Note it was writen when the last edition of wiring regs were in force, so there are some changes but it will give you a good overview.

 

[Spark123]

This one TTC?

http://www.theiet.org/publishing/wiring-regulations/mag/2005/16-elect-inst-outdoors.cfm?type=pdf

 

[Taylortwocities]

Oh yes, thanks. I knew I was going to do something after I did Ctrl C