No earth loop

[BillR3]

I would go back immediately and disconnect your made up tnc-s system. Revert it to a TT system with a newly fitted earth spike and cover the installation with a 61008 device as you cannot just go around making up combined neutral and earth systems.
BillR3

 

[scotsparky]

if it wass tt and you were getting an eath path through the water,strucural steel ect you would get 230v try it agian one all main bonding has been disconnected i would be suprise if there was an eath.
Call supply authority see what system they have installed if they say tn-c-s thenits ther responsibility to provide an suitable earth terminal.

 

[andekoch]

I would not convert to a TNCS. It sounds like it is a TT with the earth spike just not visible. If anything convert to a TT. As said before due to the construction of TNCS (PME) the dno is the one who does the change, it is (should no be) a simple connection in the domestic premisis.

A quick check of the incomming cable in the fuse block will tell you if it is TT or TNS or TNCS. TT generally will not have 'armour' and will have 2 cores, TNS will have steel armour or lead sheath and 2 cores, TNCS will have a single core with the 'armour' being half copper and half steel.