The problem with DIY or unqualified electrical work can be quite dangerous for numerous reasons. I have seen too many times in areas such as Driffield, Bridlington and Scarborough, when doing a fuse box change or rewire, the use of Incorrect fuse sizes, wrong wire thicknesses, poor connections and the use of the wrong materials for connecting wires. The most obvious reason for this being dangerous is that when connections are not properly secured they become a fire hazard. A loose connection when doing a rewire generates heat which can easily catch Fire and cause obvious damage or possibly even burn down an entire home. When moving into a new home, electrical installations and wiring need to meet stringent tests by qualified personnel in order to be declared safe against fire hazards and other potential problems. If the wiring is not certified by a qualified electrician, this could lead to all sorts of other problems such as insurance companies not wanting to pay out for damage caused by an electrical problem. I have seen this all too many times in Driffield, Bridlington and Scarborough where I have frequently worked, and at the end of the day you are probably better off hiring a qualified electrician to do a fuse box change or rewire, as this will be more cost-effective and save you a lot of money in the long run.
Example of DIY