Pme TT in same farm building

[DPG]

Did you confirm whether they are both from the same source yet?

 

[Rkidcd]

I'm onsite now having a look and it's a strange one to trace to be honest, the supply cable for the TT supply actually comes from underground with a PME sticker at the cutout but no earth block has been supplied - does this mean it has the potential to be a pme system however can't be because of the buildings use and therefore has been TT'd?

 

[Ian1981]

Sorry to bring this back up but I would like thoughts on my plan based on the above advise.

I'm going to bring 3phase PME supply across from main building to metal outbuilding but isolate the earth externally.

This means that I'll be TTing this new supply but what I need advise on is whether I sink a new Rod for this or would it be possible to use the Rod already installed for the current single phase TT supply the building uses (see original post for background info)

Thanks in advance

Can you not use the structural steel already in place as the electrode in the metal building?
Or isn't it imbedded in the ground?
It is permitted.

 

[Wilko]

I'm onsite now having a look and it's a strange one to trace to be honest, the supply cable for the TT supply actually comes from underground with a PME sticker at the cutout but no earth block has been supplied - does this mean it has the potential to be a pme system however can't be because of the buildings use and therefore has been TT'd?

Without seeing it ... May be the original DNO supply required TT installation and at some point DNO did an upgrade and it became PME, but the installation has not been updated to use it as means of earthing (may require new bonding etc).