Most work on your electrical installation will require a certificate to be issued on completion. THis certificate reassures you that the work has be carried out the the required standard and your installation is safe for continued use.
Minor Electrical Installation Works Certificate (MEIWC)
As the name suggests, if the work is minor such as adding a socket to an existing circuit then this certificate will be issued. The certificate, including any test results should be kept safe alongside any other paperwork for your electrical installation.
Electrical Installation Certificate (EIC)
For all other work on your electrics, such as adding a new circuit, replacing an old fuse board or a complete or partial rewire, an EIC will be issued. The certificate, including any test results should be kept safe alongside any other paperwork for your electrical installation.
Electric Installation Condition Report (EICR)
This is NOT a certificate as it does not actually certify anything. It is a report on the condition of the electrics on a particular day. It is a bit like an MOT for your electrics. The outcome of any inspection will be either satisfactory or unsatisfactorily and will explain what is wrong. The report may also make recommendations for improvement.