I have a 1946-built semidetached house in the UK, which has a standard 10-way consumer unit installed. Now, after having a new extension built, I need to replace it with another CU (10-way isn't enough any more; plus the old one doesn't satisfy changed regulations). I'm confident enough to do the job - and then have it inspected by the qualified electrician. Yet, for obvious reasons, I need to cut off power supply to the CU.
The picture below shows the entry point. The large red/black wires at the top are the ones going to the meter - and then from there to the CU. Is there anything on this entry point that I can use to cut off power supply? Or do I need to contact the power company?