pme or TT??

[drewandsons]

Just been to do a PIR in a house in Stoke.
When I got there I found the service head with a 100amp main fuse,16mm tails and a small 6 way board protected by a 100ma 80 amp elcb.
I realise the tails need upgrading to 25mm and therefore the main bonding which at present is 6mm will also need upgrading to 10mm.
There seems to be no earth to the consumer unit at all,so I assume the large Zs readings I am recording are due to it finding a path to earth via the pipes in the house!! and not the suppliers earth!!

If I am to put right this installation then do I need to fit an earth rod? im assuming so!!
and also is the board satisfactory or would I have to fit a board with a 30 ma main switch??
or 100ma main switch and then individual 30ma rcbo's to each individual circuit??

kind regards Graham.

 

[GT1]

are you sure there isnt a rod somewhere already..?
agree with you that its probably earthing through the pipes at the moment.
But I would explore the other possibilities.

Perhaps there is a rod but the main earth bond to it from the CU is missing?
Could it be that its supposed to be TNS and its been tampered with.. hence the missing main earth..

Think i would like some input from the DNO as what they think the earthing arrangements are at the property..
Then put that to the client if extra costs involved.
Document their answer if its anything less than getting DNO out to sort the service head..?


If nothing else, perhaps check the houses next door, either side, see what the earthing arrangements are.

Of course you could just bang in a rod until the Ze is low enough... !!
Personaly i'd like to know the reasons why its the way it is.
Depends how much time you have.