This is the final step in a design issue for my house rewire. The
situation is that I end up with a CU which can potentially pull enough
current to take out the company service fuse. Likelihood of this
happening is small, however... I'd like to protect against taking out
the service fuse with a 100A switch-fuse unit between the meter and CU.
Clearly this is not much help unless the switch-fuse trips out before
the service fuse. Simple - install a quicker blowing fuse, problem, I
would rather this fuse didn't go before the MCBs in the CU. Solution,
find a 100A fuse which will blow quicker than the service fuse but
slower than an MCB.

Any suggestions/alternatives?

Fash