There is no legal requirement to have an electrical safety check (unless it is an HMO) like there is gas but a Landlord must prove (if necessary) that they have taken all reasonable precautions to ensure the tenants safety. A minimum safety is considered to have RCD type consumer unit.
More info at http://www.electricalsafetyfirst.org.uk/mediafile/100652049/Landlords-Guides-England_Wales-2016.pdf
