You can do your own electrical work if you are competent to do so. Simple tasks such as wiring a plug are within the grasp of many people but more complex tasks, such as modifying an electrical installation, may not be.
It is particularly important that anyone who undertakes electrical work is able to satisfy the requirements of the Health and Safety at Work etc Act 1974 and the Electricity at Work Regulations 1989.
For work on electrical installations below 1000 volts AC, you should be able to work within the guidelines set out in BS7671 ‘Requirements for electrical installations. IET Wiring Regulations. Seventeenth edition’. For details, see: British Standards Institution. Other work should be carried out according to the guidelines set out in the relevant industry standard.