TT or not TT................

[Baddegg]

so in between stressing about the connection between KA and zs readings (thanks mattja) I’ve been to meet a customer who wants a pub built in his back garden (yep), tncs supply, will be no extraneous parts at all to the “pub” all plastic water and waste,incoming water is tee’d from mains which is 25mm mdpe, it’s going to be about 6 metres from the main house, it won’t be a problem to TT but will be just as easy to run relevant size earth with new swa, any advice and or opinions?

 

[Deleted member 26818]

What size SWA?

 

[Baddegg]

Havnt got that far yet spinlondon still at the basic design stages, will be a few sockets running couple of coolers/fridges, a small water heater and plenty of led lights.

 

[Deleted member 26818]

Just thinking that if you were to use 10mm2 with an earth core, then the question becomes moot.

 

[Wilko]

Get the plans - I want one too

 

[MDJ]

Bollox to TT, just extend the TNCS system as it is only 6 Mtrs away, popcorn ready here

 

[Marvo]

Best of both worlds, extend the TN C S and put a rod in as well if it's PME.

 

[MDJ]

I doubt the OP knows the difference between TNCS and PME marv

 

[Baddegg]

Ha ha thanks for replies, would 10mm be ok? Or would the earth need to match the 16mm main earth?
Sorry spinlondon this is new territory for me and I’m looking forward to getting into it,why would it become moot with the 10mm swa?

Best of both worlds, extend the TN C S and put a rod in as well if it's PME.

Thanks Marvo as stated no probs with putting the rod in but conversely the customer is not quibbling over costs, just wanted some opinions on what’s best to do assuming TT is not actually required in this instance

 

[MDJ]

Thanks Marvo

If you suck up to him hard enough he may give you a badge lol

 

[Baddegg]

Get the plans - I want one too

Me to wilko! It’s 10mtrs x 12 mtrs basically most of his back garden..

 

[Nigel]

Use the PME earth.

 

[buzzlightyear]

just run a 10mm out a s/fuse to the sockets job done .

 

[Deleted member 26818]

Ha ha thanks for replies, would 10mm be ok? Or would the earth need to match the 16mm main earth?
Sorry spinlondon this is new territory for me and I’m looking forward to getting into it,why would it become moot with the 10mm swa?

Thanks Marvo as stated no probs with putting the rod in but conversely the customer is not quibbling over costs, just wanted some opinions on what’s best to do assuming TT is not actually required in this instance

Minimum CSA for both earthing and bonding conductors where PME conditions apply is 10mm2.
If you were to use a 3core SWA to supply the shed/pub, and one of the conductors were used as the earth, then bonding requirements would be complied with.
Thus the question becomes moot.
If however you were to use 2core SWA and use the armour as CPC, then you would have a choice between TT or using the house earthing system.
Either would be acceptable, though using the house earthing system would be preferable. Only concern being whether at some point in the future, something being installed that would require bonding.

 

[Baddegg]

Thanks spinlondon much appreciated,there is no reason to believe something will be installed that would require bonding at a later date as it’s a new build from ground up we can install all services in plastic now, I think cable route permitting I’ll go with the 3 core swa that’ll be ample for what’s going in there,