Electric installation such as the replacement of a fuse box should be done by qualified individuals who are able to issue a certificate for the installation in accordance with Building regulations. In this instance a qualified electrician is your best option.
Consumer units boxed in wooden cupboard or mounted under wooden stairs are seen as a fire hazard as these materials are highly combustible.
According to building regulations your consumer unit should be enclosed in a cabinet or enclosure constructed of non-combustible material such as steel.
According to regulations, electrical equipment should not be present in shower rooms or bathroom. This includes simple equipment such as wall switches, plugs and especially consumer units.
According to regulation, gas pipes and gas meter in domestic houses, must be spaced at least 150mm from electricity meters, switchboards, electric cables, sockets, telecommunication cables, consumer units and any other conductors. Additionally, there should be a separation between a supply or distribution cable of at least 25mm for domestic pipework up to 35mm or 50mm for pipework over 35mm.
Before fitting a shiny new electrical consumer unit, it is advised to carry out an electrical Installation condition report (EICR). This test will establish the health of the electrical installation in your house and enable you and your electrician to decide if the existing wiring and circuits are fit for purpose.
The time it takes to replace a fuse box may vary on the size of the property as well as the conditon of the exsiting wiring. A typical replacement geneally takes around half a day.