Just a quick question

[Doomed]

In a large yard, incomer in corner, TNS, feeds some switch gear and then a long length of SWA to garage in other corner of yard about 100m away.
By garage I mean a big garage, water canteen and all.
Readings are good at the garage sub board.

There is a bit of me that wants to TT the garage, but I know with the ground there I will struggle to get a good reading.

As its TNS I don't have to TT do I?, so please tell me to stop being stupid and leave it alone.

 

[Jon Bateson]

Stop being stupid and leave it alone

 

[Doomed]

Thank you

 

[Pete999]

Thank you

Your welcome

 

[Charlie_]

Do you see why you’re being stupid?

 

[davesparks]

This is not necessarily being stupid, but the decision is not based on distance as seems to be suggested in the OP.

You need to understand why some installations may have a seperate TT earthing system set up at outbuildings before assessing this and making a decision.

Is main bonding required at the outbuilding? If it is not then you can stop there. If main bonding is required at the outbuilding then does it have a suitably sized cpc or bond from the MET through to the outbuilding?
If it does not then you need to assess whether it is better to install it or to convert the outbuilding to TT, cost can have an influence on this decision.

 

[Jon Bateson]

I wasn’t commenting on the rights or wrongs of said earthing arrangement. I was simply granting the OPS wish to be told to stop being stupid and leave it alone

 

[Welchyboy1]

With a tns system your requirements for minimum bonding conductor size is significantly less than pme, hopefully at least your swa csa should be of a sufficient size to comply even if there is no additional earth conductor core within the swa, as youve said the readings comply

Hope i have understood your point?

Why would you want to TT it?

This then brings up the issue for the need of global rcd protection likely required for the garage which can sometimes have equiptment that might be a problem or even a safety issue if nuisance tripping/ and or high earth leakage occurs

In my opinion your likely making future problems for yourself

 

[Doomed]

Again, thank you.
I sometimes over think and start doubting my knowledge and memory. You have all put my mind at rest. (well, one small part of it at least).

 

[davesparks]

Do you see why you’re being stupid?

Is he being stupid?

 

[davesparks]

Again, thank you.
I sometimes over think and start doubting my knowledge and memory. You have all put my mind at rest. (well, one small part of it at least).

So what is the answer regarding the need for main bonding?
Is it required and if so does the submain include an earth of sufficient size to provide main bonding?

 

[Charlie_]

Is he being stupid?

Don’t know, that’s why I asked him if he knows why