Consumer Unit Upgrade

[IPS]

I am currently assessing the replacment of an exisiting fuseboard to a new split CU and seek advice that I'm unable to find reference to in 7671.

The exisitng fuse board is approximatley 8mtr from the Meter, does the new CU need to be repositioned closer to the meter and all the circuits extending? I have a maximum figure of 3mtr for the consumer tails length in my head

Thank you

 

[pc1966]

25mm would be the minimum for 100A usually, you would have to check VD (unlikely a problem if only 8m) and cable ratings in the installation method chosen if you can realistically get anywhere near the 100A demand.

If they only need 60A then a 60A fused-switch and 16mm would be fine.

 

[richy3333]

Sorry I am slighly more confused with the Consumer Tail sizes.
The DNO fuse is 100A TN-C-S earthing arrangement > 25mm Tails to Meter > 25mm Tails Meter to Isolator > I need to know what is the minimum size cable CSA from the Isolator to the CU.

Thank you in advance.

If you want the maximum amount of supply possible you would have to use and 80A fuse in your switched fuse isolator due to selectivity. Cable sizing is then dictated by the usual variables?

 

[IPS]

Thank you all. Very much appreciated.