Outside sheds TT or not TT

[sevuk]

This is a topic we discussed while doing 2391. It's not something I've really thought of or need to for that matter.

If a shed far down the garden has its own CCU, should it be fed with a two core armoured glanded into a plastic box and have its own electrode?

The theory being especially if it is a metal clad shed, isn't there a risk of electric shock if the shed is brought up to the same potential as the house if there is a fault in the house?

Small loads like lights would more than likely be fed from a circuit in the house and if rcd protection is provided this should be adequate, but a workshop should be in its own faraday cage should it not? Or at least have an earthing conductor the same size as the bonding conductor in the house.

What do you guys do?

 

[Pete999]

This is a topic we discussed while doing 2391. It's not something I've really thought of or need to for that matter.

If a shed far down the garden has its own CCU, should it be fed with a two core armoured glanded into a plastic box and have its own electrode?

The theory being especially if it is a metal clad shed, isn't there a risk of electric shock if the shed is brought up to the same potential as the house if there is a fault in the house?

Small loads like lights would more than likely be fed from a circuit in the house and if rcd protection is provided this should be adequate, but a workshop should be in its own faraday cage should it not? Or at least have an earthing conductor the same size as the bonding conductor in the house.

What do you guys do?

 

[sevuk]

Thanks Pete,
I think that definitely closes that discussion.

 

[Pete999]

Thanks Pete,
I think that definitely closes that discussion.

I aim to please, most of the time.

 

[Midwest]

Arrgh what the hell....depends if the DNO has a particular dislike on the practise of exporting or extending (whatever) their PME supply or if there's anything extraneous, that make a TT more cost effective.

 

[sevuk]

Arrgh what the hell....depends if the DNO has a particular dislike on the practise of exporting or extending (whatever) their PME supply or if there's anything extraneous, that make a TT more cost effective.

When would exporting a pme supply be allowed?
I can't see that being correct, but I've never been involved in it.
Without even thinking about it, I've often run in an earth cable with an armoured as part of the design, I've never tapped off a neutral.

 

[Midwest]

Done a few times to detached garage for example, DNO had no preference, and TNC-S is mostly better than brilliant TT. The likes at the IET don't think so mind!

 

[Octopus]

Come the 18th we will be putting in a rod on tncs ....... The regs writers just don't have as clue what they are suggesting ...

So export the earth and add as rod. ....

 

[Midwest]

Come the 18th we will be putting in a rod on tncs ....... The regs writers just don't have as clue what they are suggesting ...

So export the earth and add as rod. ....

Not yet, they might realise how impracticable it is, other than in new build.

 

[sevuk]

Not yet, they might realise how impracticable it is, other than in new build.

What are you talking about, I have a sledgehammer in my toolbag, don't you?

 

[Octopus]

Not yet, they might realise how impracticable it is, other than in new build.

Easy with a new shed install ...

 

[The Ghost]

Yeh thought I'd get ahead of the 18th and install a rod in 13th floor flat. People downstairs didn't think much of the rod sticking through their ceiling. Fussy!

 

[Spud28]

TBH honest I did a freebie job for old lady who lives next door, I thought about all scenarios, exporting a 16mm earth, tt'ing etc and went with what Murdoch suggested, PME and bang in a rod for good measure......

 

[Midwest]

What are you talking about, I have a sledgehammer in my toolbag, don't you?

Is that a have?

 

[bigspark17]

Depends if there are extraneous parts & if the out building is being used as an agricultural building for livestock.. if no to both then exporting via a adequate cpc is fine imo..

 

[Midwest]

TBH honest I did a freebie job for old lady who lives next door, I thought about all scenarios, exporting a 16mm earth, tt'ing etc and went with what Murdoch suggested, PME and bang in a rod for good measure......

Freebie, how much did the rod cost ya ?

 

[Spud28]

A cup of tea and a homemade welshcake or three!