Spur to outbuilding TN-S

[D Skelton]

I'm having a blonde moment here???

Supply is TN-S, technically, could you spur off an existing RFC in the house to provide power to an outbuilding as long as you don't export the earth??? Connecting the earth rod from the RCD SFCU in the outbuilding?

If you can, this is not in a million years what I would choose to do, I just wanted to know if it was technically possible???

I can't see any reason why not, but as I said, blonde moment and not got regs book to hand.

Cheers in advance peeps

 

[Guest55]

with tn-s you can extend and use the suppliers earth path to outbuildings , garages , decking , hot tubs etc etc without using any earth rods.
yes , very blond.
;-)

 

[D Skelton]

with tn-s

Don't you mean TN-C-S?

 

[Guest123]

TN-S is fair game, no restrictions on extending/exporting at all.

 

[Guest55]

No , youre the one getting mixed up.
tns = seperate earth
tnc-s = combined N&E

 

[D Skelton]

Don't you mean TN-C-S?

What am I on about???

Massive blonde moment me thinks???

 

[telectrix]

bimbo blonde.

 

[D Skelton]

No , youre the one getting mixed up.
tns = seperate earth
tnc-s = combined N&E

Yes I know the difference lol

 

[Guest55]

i'll get your hat & coat.

taxi for d. skelton lol.

 

[telectrix]

back to essex?

 

[D Skelton]

So yeah, TN-S is ok to export, I get that, and I get not being able to extend TN-C-S in case of broken neutral, easy stuff and I have always worked this way, but having just read this moments before my OP, it sure as hell makes the document confusing: View attachment Garage-Shed Supplies.pdf

Let me rephrase that, it sure as hell makes the document wrong! (or at least fig1 and fig2)

Hence my blonde moment

 

[Guest55]

whats wrong about it ?
looks like accurate guidance to me.
you do realise that the example diagrams are based on an assumed PME / TNC-S supply ?

 

[D Skelton]

whats wrong about it ?looks like accurate guidance to me.you do realise that the example diagrams are based on an assumed PME / TNC-S supply ?

Exactly, it's a PME supply and yet in Fig1 and Fig2 there's no mention of an earth rod.

 

[SPARTYKUS]

You CAN export Tncs to an outdoor building!!!!!


If it has services they need a main bond too so the equipotential zone is extended.


TNS is just the holy grail before the laws of physics changed in the 50s/60s.

 

[telectrix]

nothing to stop you exporting the pme ( or extending the equipotential zone ) and banging in a rod as well.

 

[D Skelton]

I thought the whole idea was that you couldn't extend PME outside of the equipotential zone? Or was I taught wrong?

 

[Guest55]

Exactly, it's a PME supply and yet in Fig1 and Fig2 there's no mention of an earth rod.

dont make me use the facepalm poster.
;-)

 

[D Skelton]

dont make me use the facepalm poster.
;-)

Haha, seriously tho, am I missing something?

From what I see in Fig 1 and 2 the PME has been extended outside of the equipotential zone as it's a detached garage.

I may be wrong but this is what I was always taught. What am I getting wrong?

 

[pencilpusher]

The EZ is purely extended to the garage. By main bonding any extraneous conductive parts within the garage directly back to the MET, the EZ is "extended" or "exported" and is now a larger EZ.

 

[Guest55]

you seem to have the belief that you cannot use a tnc-s earth connection beyond the building where the supply is located , yes ?
wrong , you can , but there are instances where a earth rod or TT conversion may be preferable , and instances where the dno would rather you didnt do it.