How do I tell if an electrician is "qualified" in the UK?
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  The Department for Communities and Local Government (DCLG) authorises bodies to operate schemes under which their members are deemed competent to self-certify that their work complies with the building regulations for England. A similar scheme is authorised by the Welsh government.


At a minimum, you should expect an electrician to be registered under one of the "competent person schemes". For example Stroma, NICEIC. You can ask an electrician for their registration number and registration body's name then check them on that body's website.