With the exception of HMOs there is no statutory requirement to have safety checks on electrical installations. However, the Landlord and Tenant Act 1985 requires that the landlord ensures the electrical installation is safe when the tenancy begins and that it is maintained in a safe condition throughout that tenancy.
Fixed installations include the fixed wires, wall sockets, light fittings & switches etc. Items such as cookers and wall heaters are also considered part of the fixed installation if they are permanently wired in, rather than having a plug fitted for connection to a wall socket.
There are additional requirements for HMOs (whether licensable or not), which includes an inspection of the fixed installation by a competent person (generally a qualified electrician) to ensure safety and that the electrical system complies with current electrical regulations. This must be carried out at intervals of no more than five years and you must obtain a copy of the certificate, specifying the results of the test.
It is regarded as good practice for landlords to adopt a similar approach to other, non HMO lettings.