Running 2 supplies from 1 DNO Head

[LED Lighting]

Is there any better way of doing this?
1 DNO Supply - 100A
2 Buildings - not connected to each other.
DNO on Main House - PME Supply
Holiday Cottage run by 25mm SWA (2 Core) from House Supply (underground)

25mm running 6m from DNO to CU - 100A Iso fitted
2nd Iso for Holiday SWA Supply - 80A
Holiday Cottage on TT - unless it can go to PME - to my memory it can't

Metal CU in Main House all RCBOs
Insulated CU in Holiday Cottage on split load

Any Thoughts??

 

[ChrisElectrical88]

Sounds good to me so long as all installed correctly. The Cottage will need to be TT i think, not 100%, someone on here will give you a defiant answer.

 

[overskilled]

How far are they apart?
Not 100% but if the distance isn't too great, earth loop impedance ok (and suitable protection installed) then a 16mm2 earth should be enough to extend the equipotential zone?

 

[LED Lighting]

How far are they apart?
Not 100% but if the distance isn't too great, earth loop impedance ok (and suitable protection installed) then a 16mm2 earth should be enough to extend the equipotential zone?

Only 10m apart - but their is no connection apart from the electrical cable and water pvc pipe between them.

My understanding was if they are not connected together structurally then a TT System is required

 

[overskilled]

I'm shattered so again admit I may be talking out of my rear end.....
Neither of them is a caravan so PME earthing isn't prohibited by BS7671:2008(2011)
How is it any different to the DNO looping the supply between 2 heads?
10 metres is enough that you couldn't touch extraneous conductive parts, but close enough that the TT might have problems given the PME is so close by?
(e.g. the situation someone quoted either here or on the IET boards - customer supply was TT but neighbours close by were all PME, DNO came out and changed the customer to PME)
The way I look at it is...as long as the earth loop is low enough resistance then using the supplier earth is going to be safer than using a Rod. Plus your splitting the tails so the effect of one install shouldn't affect the other (well unless the cutout fuse blows...) Essentially its no different to a detached workshop etc??
Though freely willing to admit I might be wrong.......

 

[LED Lighting]

Problems - what kind of problems - cant imagine how a TT being close to a PME could cause problems unless a fault occurred.

At the end of the day the Earth is only there as a safety backup in case a fault does occur - it serves no other purpose

 

[Engineer54]

Perhaps LED/Spinks can explain to me why the DNO's PME supply can't be used at the second property??

 

[Silly Sausage]

the Earth is only there as a safety backup in case a fault does occur

That phrase amuses me!

 

[Lucien Nunes]

it serves no other purpose

Except when it part of it is also the neutral, in which case it carries current, experiences voltage drop, takes on various potentials at different places...