out building supplly

[the pict]

I know the guide states a supply to outbuildings should come via a MCB,but, if the MCB is on a RCD rail and that MCB supplies the outbuilding CU via a main switch,RCD,MCB, is that not a whole lot of gubbins that realy is not required, can the supply out not be taken direcly from the switched side of the parent CU main switch, in fact would it not serve better if the supply out was take from a couple of henlys before the parent CU.
Pict

 

[truckster]

The outgoing cable to the outbuilding will have to be protected by an mcb at least and possibly an rcd if the loop impedance is too high.

 

[the pict]

Cheers, this is project I have been asked to look at,Its' a PME, with 2 outbuildings and a static caravan,1 is a propagator,2 is a chill room, and the van all are fedd from a single 100A supply but at present there is a lot of nuisance tripping mainley I think when the chill room compressor draws start up current due in part to the lack of discrimination between RCD's, this I can sort but while I am at it I would like to split the load up better that is I thought that if I split it at a point prior to the parent CU and segregate it into 3 smaller CU's within the main building the cable run is 20 metres so VD is well within limits I was wondering if this solution had merit.
Pict

 

[telectrix]

and note that the caravan must be dissociated from the PME earth and have it's own TT system ( earth rod.).

 

[the pict]

Ah yes now I had not considered that at this stage thanks for jogging my memory, thankfully it should be ok with one as the ground is wet and deep, I remember one I tried to put in for a van in a wooded area, scots pin and fir thirsty beggers, the ground was dry as the dessert and as soon as the rod went through the roots it literaly disappeared never ever got it back ,
Pict