Usually in a domestic environment, the most important part of the installation is the circuit protection, ie the Consumer Unit or Fusebox back at the main intake. If yours is more than ten years old, it is likely to need replacing.
To fully comply with regulations, residual current protection has to be installed for almost all circuits and this is usually done by one of two methods:
A new Split Board Consumer Unit having two main RCDs (residual current device) each protecting several circuits.
A new ordinary Consumer Unit with an RCBO (residual current breaker with overload) for each circuit.
Either option will of course give the required residual current protection but the second provides dedicated protection, so when (not if) a fault occurs on a circuit, ONLY that circuit will trip. We strongly recommend option 2 if budget allows.
There are several shortcuts that contractors can make when replacing a fusebox so please be wary. It is very important that you receive an Installation Certificate with a Schedule of Test Results and a Part P certificate assuring compliance with the Building Regulations. You should also receive a full and precise circuit list, not just sticky labels showing ‘sockets’ and ‘lights’.