In Canada and the USA, third-party certification of electrical products is mandatory by law. However, the law allows manufacturers to choose from a number of alternative certification marks and approval labels that are equally recognised by the Regulatory Authority Having Jurisdiction (AHJ) in both countries. When a product bears the mark or label of any of these accredited certifiers, it can then be marketed and sold in the North American market.

Accreditation demonstrates that the organisation in question is fully qualified to test and certify products to the standards for which it is accredited. To certify a product for a given market, all accredited organisations must test the product to the same applicable national and/or international standards.