exporting earth

[PIP IOM]

Hi fellas

I'm a bit confused re the exporting of earth issue. I'm gradually rewiring a big house (TT). They now have told me they're having a summer house and need power to it (shed with windows) and need power to a carport. Both are not attached to the main house (each 10m ish away). What is the spec for this re earthing ie do I have to rod the 2 outbuildings seperately and isolate earth exported from main house in my SWA's.

Wasn't intending to have a dedicated small C/U in each just a feed spurred down for lights .

 

[Tooold]

There are a lot of threads on this already, thats all I'm prepared to say!

 

[Evans Electric]

Oh no.

 

[danny7299]

Noooooooooooooooooooooo not again !!!!!!!!!!!!!!!!!!

 

[Andy™]

its only TNCS that shouldnt be exported

 

[initforthemoney]

[quote name='Andy

 

[Andy™]

Why not?Done it many times and will continue to do so.

The only time i dont is if there are services in the outbuilding and it is not possible to run a bond back to the origin.

same reason you cannot use TNCS for a caravan

along with the fact that the DNO may not allow you to export TNCS anyway

 

[initforthemoney]

[quote name='Andy

 

[PIP IOM]

oops just learnt how to search historic threads

 

[tom1]

oops just learnt how to search historic threads

you will be all weekend reading expoted earth threads

 

[Evans Electric]

I hope Steptoe doesn't get wind of this.!!!

 

[green-hornet]

I hope Steptoe doesn't get wind of this.!!!

He already has but decided not to rise to the challenge

Besides he is busy rodding some nurses accomdation !! ]

 

[Evans Electric]

Is that a metaphore for something ?

 

[PC Electrics]

He already has but decided not to rise to the challenge Besides he is busy rodding some nurses accomdation !! ]

Some people have all the luck!

(and there I was, studiously ignoring this thread)

 

[M107]

He already has but decided not to rise to the challenge Besides he is busy rodding some nurses accomdation !! ]

:^O

Never invited anybody else:C

 

[matt.leung]

sorry trying to learn here,

what is meant by an exported earth ?

matt.

 

[Robin Spark]

Using the earthing from one building, taking it outside of the equipotential zone and then re-using it at another location ie remote garage, shed outbuilding, nursing accommadation at the bottom of your garden etc.

Eg

If you have TNCS supply at origin in house and want to supply power to lets say a remote garage then if you did this in 2 core SWA you would connect armour to earth at supply side but then gland off into plastic adaptable box and you would not take the earth wire from the banjo into your garage cu.

You would then provide an earth stake at garage and make the garage a TT install. Hope this makes sense.

I think its all to do with lost neutral in the suppliers side and a difference in potential with the TNCS earth and the general mass of earth which can cause shocks.

 

[ianmacd]

Why not?Done it many times and will continue to do so.

The only time i dont is if there are services in the outbuilding and it is not possible to run a bond back to the origin.

Think EDF may have something to say about that then since they have threatened to withdraw service if TN-C-S is exported on their network.

 

[ADS]

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

It's 16th edition but still applies - that's all I'm saying

 

[Andy™]

I think its all to do with lost neutral in the suppliers side and a difference in potential with the TNCS earth and the general mass of earth which can cause shocks.

dont even need a lost neutral to have a voltage difference between 'earth' and the ground your standing on