Convert mixed earthing arrangements to TN-C-S Electrical Advice

Convert mixed earthing arrangements to TN-C-S Discussion ThreadConvert mixed earthing arrangements to TN-C-S Electrical Advice

Hello, I've been asked to install another DB at a property.

With reference to the photo below I notice that there exists at the moment multiple earthing arrangements; a mixture of TN-C-S (with 25mm tails and 16mm CPE) and TNS (with 10mm CPE). It looks like the incoming TN-C-S has been added more recently alongside a legacy of TNS boards over the years. I intend to flag this as an issue to the customer which should be resolved either prior to or at the same time as adding another DB (DB6).

In order to do so, I propose to:
1) Replace the MET block with a larger one,
2) Connect the incoming 16mm CPE to the new MET block,
3) Connect DB3 and a new DB6 CPE to the new MET block,
4) Disconnect the 10mm CPE which currently heads up the wall and outside (presumably to an earth rod), thereby converting all the other existing DBs (1, 2, 4 and 5) to TN-C-S

Would anyone recommend a different course of action?

Many thanks,
John.

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