Achieving Harmonization of Product Safety Standards

Donald A. Mader and Søren Krøigaard

Donald A. Mader

The first Danish national Heavy Current Regulations—for years the mandatory electrical safety standards for all electrical equipment sold in Denmark—were developed in 1887. Underwriters Laboratories (UL) Inc., which was founded in 1894 in Chicago, began developing standards for the United States in 1902. Some of Europe's oldest electrical safety and national certification bodies were formed later, such as VDE in Germany in 1920 and DEMKO in Denmark in 1928. From these beginnings, development of U.S. and in ternational electrical product safety standards began. UL's standards often vary greatly from IEC standards. Manufacturers worldwide are increasingly requesting that these standards be harmonized to enable them to design truly global products that comply with one set of global standards.

Development of Safety Standards

Soren Kroigaard

From the early part of the twentieth century, the development of safety standards in North America differed greatly from that in Europe. The divergent philosophies were rooted in the construction differences required for domestic dwellings and workplaces in Europe and in North America. In the United States, houses and buildings were often constructed of wood, which considerably increased the potential fire risk from faulty electrical apparatus and appliances.

The domestic supply voltage in the United States, then and today, is approximately half of the European voltage range. For a given electrical resistive load in kilowatts, this means that the current drawn in amperes is twice as much in the United States as in Europe. From a fundamental electrical equation, the heating effect from the resistance of electrical connections, such as those in an electricity supply cord in the home, rises as the square of the current running through it. So if the current is doubled, the heating effect increases at a far greater rate, according to the square law in a resistive load, and thus greatly increases the potential fire hazard.

For these two primary reasons, UL standards originally focused on the flammability of materials adjacent to electrical apparatus. Because European supply voltages are twice as high as in the United States, IEC and related standards focus instead on the potential for electrical shock from live parts and the electrical insulation necessary to prevent danger from shock or fire. IEC standards and European norms, therefore, tend to center around the dielectric strength of insulation under extreme test conditions and creepage and clearance distances, which are the insulation's dimensions and position with respect to live parts.

The Need for Harmonization

UL relies on industry to provide the encouragement and support for harmonization of existing UL standards (80% of which are American National Standards) with IEC standards. Typically, UL assesses the need for and desirability of harmonization based on industry information regarding target markets. Such a policy requires significant resources to participate in many IEC standards committees.

Generally, it is in everyone's best interest to adopt worldwide harmonized standards. The harmonization process must take into account the technical requirements of the various U.S. installation codes (most of which are also American National Standards), and the current levels of component, product, and system safety expected to protect American consumers in their home and work environments. This is critical to UL's more-than-100-year-old core mission of public safety.

UL will continue participating in ISO and IEC committees to develop new internationally accepted standards, especially when no regional, national, or international standard currently exists.

When no UL standard exists, the preference should be to adopt an existing international standard as long as the requirements address the level of safety expected by American consumers and the U.S. safety system.

When no ISO or IEC standard exists, the preference should be to adopt an existing UL standard as an international standard, provided that the requirements address the levels of safety expected globally and that the standard meets all national safety requirements.

For existing UL and ISO or IEC standards that address the same general product categories, the preference should be to harmonize the UL standard with the ISO or IEC standard (or the ISO or IEC standard with the UL standard) with as few national deviations as possible. Any national differences should be justified by documented national legislation, documented national legal precedent, or documented technical prerequisites of the national safety system or the national installation code or practice. Any other national differences should be avoided by introducing technically and experience-supported national basic safety requirements into the current ISO or IEC standard. If no other possibility exists, then alternative or harmonized safety-equivalent evaluation criteria that will not result in possible barriers to trade should be negotiated.

The History of Electrical Safety

Between the First and Second World Wars, the use of electricity in Europe and the United States increased rapidly, particularly in domestic dwellings and businesses. The first European organization for electrical safety standards, known as Installations Fragen Kommission (IFK), began operating in 1926, but stopped at the start of World War II. In 1946, when peace had been restored, the European International Commission on Rules for the Approval of Electrical Equipment (abbreviated to CEE) was created, phoenix-like, from the old IFK organization.

The International Electrotechnical Commission (IEC) had already been founded in 1904 in St. Louis. Its first rules and statutes were drawn up in London in 1906 and finally agreed upon in 1908. However, IEC had little authority for many years, and in Europe CEE standards were generally used for electrical safety standardization. Gradually, IEC adopted most of CEE's standards, including those for household appliances in 1958.

In Denmark and other European countries at that time, all electrical products had to be tested in national safety laboratories for national safety marks, such as DEMKO's D-Mark or the VDE Mark for Germany. These national marks were affixed to the product to attest that it had passed safety testing to national standards before being marketed in that country. In those days, the national standards of European countries were often CEE and IEC standards, but contained national deviations.

Following the formation in the 1970s of the European Economic Community (EEC, which later became the EU), harmonization of IEC standards and European national deviations began. Such harmonization was intended to create a more level playing field for manufacturers. In 1977, a mutual recognition agreement, known as the CENELEC Certification Agreement, provided for the mutual acceptance of test results between European countries.

The harmonization of standards first resulted in harmonized documents (HDs), which are being phased out as they migrate into the current harmonized European norms (ENs). ENs and the remaining HDs for electrical equipment are published by CENELEC, the European Committee for Electrotechnical Standardization. More than half of all existing ENs are derived from IEC standards.

Suggestions for new ENs, however, can come directly from the European Commission (EC). If a standard is likely to be adopted, a parallel-path voting system between IEC standards and ENs now ensures commonality between the two standards. However, under special circumstances the committees may agree on a separate voting to determine the two standards. The two organizations are working in parallel and ever more closely, which has reduced the total time spent on writing ENs from seven years to only three to four years. The organizations plan to reduce this time even further.

With entry into the EU came acceptance of European legislation—including the CE marking directives—with the objective to lower barriers to cross-border European trade. The CE marking directives, however, have had implications for product safety. CE marking of electrical products often refers to the Low Voltage Directive (LVD). Today, CE marking under the LVD is supported by ENs, although their use to demonstrate compliance for CE marking under the LVD is not mandatory.

The DEMKO D-Mark became voluntary for electrical equipment after 1978. It is currently an international, third-party safety mark awarded following successful safety testing of electrical products to ENs or IEC standards. This provides a gateway for exports through which most major international safety marks can be obtained.

Clarifying the CE Mark

The LVD came into effect in 1973, but CE marking did not come into force in the EU until the 1990s. At that time, what are now commonly referred to as the CE marking directives, including low voltage, machinery, and electromagnetic compatibility directives, began to take effect. Many other directives, including more CE marking directives, have since been created, and more are being developed.

Many manufacturers demonstrate compliance, particularly for the LVD, through self-declaration whereby no independent, third-party testing is necessarily required. The use of relevant ENs is not compulsory to demonstrate compliance for CE marking; however, in practical terms, it is usually the easiest way to do so.

The directives are developed with direct references to the ENs, and, unless a product incorporates a new design feature that could render parts of the appropriate standard unnecessary, reference to ENs in their entirety is normally the simplest way to document a product's compliance with the requirements in the directives. For example, using a door-interlock switch to isolate an electrical supply may mean certain creepage and clearance dimensions that might have been an issue in a previous version of the product are no longer a problem in the new design. Some equipment is not covered by any EU directive, but safety requirements for such products often become part of an individual European country's national legislation. For example, plugs for use in domestic dwellings must still meet national requirements such as the Danish Heavy Current Regulations as well as the pan-European General Product Safety Directive (92/59/ EEC). Standards for electrical plugs and sockets may be among the last electrical equipment in Europe to become harmonized.

Mandatory CE marking was introduced by an EEC white paper in 1985, but was never intended to be a safety marking system. It is only an indication to European customs officers and to authorities within the European community that the importers or manufacturers believe their products meet relevant EU directives for distribution throughout the European community.

The great weakness is that consumers have begun to regard the CE mark as a mark of safety. Because CE marking, under certain directives, can be applied by a process of self-certification, the issues of product safety and burden-of- evidence under product liability legislation are beginning to rear their heads.

European market surveillance authorities recently found CE-marked products for sale that, upon examination, did not meet the appropriate directives and their underpinning standards. The public's misperception of the purpose of CE marking is beginning to discredit not only CE marking, but also the philosophy of safety marking. But a backlash may be developing in which manufacturers are requesting recognized national marks of third-party certification to be applied along with their CE mark. Both product liability legislation and the manufacturers' need to demonstrate due diligence and best practice with regard to product safety may present a fresh challenge to the concept of a CE mark being affixed alone on a product.

The Press for Harmonization

Although the process of harmonizing standards worldwide is under way, it will take considerable time and effort to achieve complete harmonization. But what does this imply? Safety marks around the world are often effectively passports for exports. They are often necessary for products to enter and be distributed in a given country. Various safety marks are required by different countries and are awarded following testing to often quite different standards.

UL's answers to these issues are to maintain the pressure for harmonization, but also to offer packages of marks as immediate solutions. UL's organization reaches around the world, not only into different countries, time zones, languages and cultures, but also into different safety standards' development organizations. UL has links to many national organizations by offering their countries' safety marks.

This enables the global UL organization to issue marks to take manufacturers' products from any point of manufacture worldwide to almost any other point for distribution and sale while still progressing on the issue of harmonization. Until standards are harmonized, a package of different marks can provide manufacturers access to European markets. The package of different safety marks is as relevant to an exporter based in Germany as it is to manufacturers in Thailand or the United States. Such a packaged solution may also be combined with other certification systems—even with assistance for CE marking.

Standards harmonization on a global scale brings together the collective expertise of varied cultures, many of which have traditions that significantly affect their national safety systems. Therefore, if international standards harmonization is the desired result, a strong spirit of cooperation and a demonstrated willingness to compromise must be mandatory ethics of IEC standards committee participants and the national committees they represent. Cooperation and compromise will go a long way toward achieving our mutual goal of one standard, one conformity assessment, accepted worldwide.

Donald A. Mader is executive vice president and chief operating officer, Americas, for Underwriters Laboratories Inc. (Northbrook, IL). He directs all U.S., Canadian, and Latin American service and program operations for UL. He serves as a liaison member of the USNC/IEC executive committee and as vice chairman of USNC/ IECEE. Søren Krøigaard is managing director of UL-DEMKO (Herlev, Denmark). He was formerly manager of testing and certification services.