Every company authorised to perform work on electrical systems in Norway must be listed in the Electrical Enterprise Register (Elvirksomhetsregisteret). Check whether your electrician is authorised.
It's illegal for companies to perform electrical work if they are not included in the Electrical Enterprise Register. It's your duty to check that the company you're hiring is included in the Register.
The Electrical Enterprise Register lists all the companies, including sole proprietorships, authorised to perform electrical work in Norway. You can also see which types of electrical work they are authorised to perform.
The name that appears in the Register is the name of the company, e.g. Hansen Elektro AS. The Register also contains contact information.