Circuit protection devices, like most items involving product or public safety, are regulated and/or tested by some agency.  This is done to confirm compliance with industry or legislative standards.  The agency, depending on the country involved, may be a government department or an independent organization which may or may not have close ties to the government.  While there are several independent laboratories in the United States, the most dominant for circuit protection devices (circuit breakers and supplementary protectors) in the commercial and industrial marketplace is Underwriters Laboratories, Inc. (UL).  Headquartered in Northbrook, IL, UL works closely with several government agencies to establish standards to assure product and public safety.

With origins dating back to 1893, UL now maintains more than 1,000 standards for safety.  Test labs are located throughout the country, with product safety reviewed under major categories such as Electrical; Burglary Protection & Signaling; Casualty & Chemical Hazards; Fire Protection; Heating, Air Conditioning & Refrigeration; and Marine.  Under these standards, UL’s engineering investigations and studies are carried out following strictly defined procedures.  The standards are usually developed through joint agency/industry committees, and submitted to the industry for review and comment prior to adoption.  Depending on the complexity of the standard, several iterations of this process, and a period of several years may occur before a standard is adopted.

For more information on Underwriters Laboratories go to www.ul.com