TN-S earthing & company fuse?

[MikeGB]

I have to replace on old rewireable CU and update the earthing, but I am a bit worried about the main company earthing cable being too small and the fuseholder says 60Amp (house is 1960's) which doesnt look good against my new cu with its 100A main switch.
Its a detached house and adding up the few things that come to mind like 2x10Amp aircon units to go in plus 9kw electric shower, 30Amp supply for my Mig welder and plasma cutter (occasional use), so its looking like my supply may be a bit on the small side.
Tails are 16mm and replaced in the last few years by the local elec co. But they didnt attempt to alter the earthing arrangements to larger than whats there which I think is 6mm.

Advise please on how to proceed, I do have a 60amp main switch after the henley blocks so can isolate to fit the new CU and can wire back in 10 or 16mm earth back to the earthing block.
Will the company alter their earthing for free to a larger size? Do they uprate the fusing on the supply cable as needed, is it usually oversized so can accept say 100Amp main fuse?

I will attach a couple of pics to assist.

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[JohnD]

the earth wire is yours, it does not belong to the electricity co. However if you tell them you have an old clamp on the sheath and there is a risk the cable will be crushed when you re-tighten it on the new earth wire (DON'T CRUSH IT!!!!) they may provide you with a sweated-on earth terminal or PME. they might do this free or they might charge you £60 to £100 which will be money well spent. Tell them the service head and fuse carrier is a very old one and they may replace that too.

You can replace the undersized main earth cable with 16mm G&Y. Main bonding to the gas and water services should be done in 10mm. this is not notifiable work so you can do it yourself. If you have a 16mm cable ready in your earth bock, you can ask the company to connect it to their new earth terminal if they provide one. Otherwise they will just re-connect your inadequate old cable since the cable is your responsibility.

The 100A main switch is a modern CU is quite normal even on a 60A fused supply. It must be equal to or greater than the fuse rating.
The planned load will have to be calculated from the all appliances that will be connected to it, reduced using Diversity factors

A 60A main fuse is quite common in an ordinary house. If you blow it with excessive loading the electricity co will replace it and may upgrade you to 80A or 100A. This will require 25mm tails not the 16mm it looks like you have.
You can't believe anything you see on a fuse carrier.

It does not sound like you have the level of competence necessary to replace your CU and do all the testing and notification that is required.

Ask you local council building Control Office for their leaflet and charges.

It will probably work out cheaper (and better) to have it done by a qualified electrician who is a member of a self-certification scheme.

 

[MikeGB]

Thanks for the reply and advise John, after 40yrs as a qualified industrial electrician mainly on machinery repairs/faultfinding I will admit to having had little to do with domestic installs for the last 30yrs and although I feel I should be able to do the CU work competently, your right I cant test and certificate it.

 

[JohnD]

no offence intended