Two recent threads about moving a CU mentioned that an additional 100
Amp DP isolator was fitted after the meter. When is this necessary?

As my installation doesn't have one I will need to break the seal and
pull the cutout when I eventually swap my CU for a 17th edition one.

Meter is in cupboard outside, and about two meters of tails though the
porch wall to the CU.
Supply is TN-S (I think).

--
Graham.
%Profound_observation%