Maryland Code, Business Occupations and Professions § 6-606

(a) A master electrician shall display the master electrician's license and the license number conspicuously in the principal place of business of the master electrician.

(b) Each electrician advertisement in the name of a person who engages in the business of providing electrical services shall contain the license number and name of a master electrician or holder of a journeyperson electrician license whom the master electrician employs and designates to direct and control the provision of electrical services through the business of the person.

(c) A licensee shall give the State Board written notice of any change of name, address, or employment from what appears on the current license at least 10 working days before the change is to take effect.