All electrical materials, devices, appliances and equipment shall have the maker’s name, trademark, or other identification symbol placed thereon, together with such other markings giving voltage, current, wattage, or other appropriate ratings as may be necessary to determine the character of the material, device, appliance or equipment and the use for which it is intended; and it shall be unlawful for any person, firm or corporation to remove, alter, change or deface the maker’s name, trademark or other identification symbol. (1933, c. 555, s. 2; 1989, c. 681, s. 1.)