Some well-known safety standards will soon be obsolete. Probably the biggest and most comprehensive change is the imminent discontinuation of IEC 60950 and IEC 60065 at the end of 2020, which are to be replaced by IEC 62368. This standard deals with the safety of information technology equipment, including electrical business equipment. Both standards have been extensively amended over the years to keep pace with technology and have also been applied in other new areas where there were no application-specific standards, such as industrial automation.

The reason for the replacement of these standards is the merging of functions in modern electronics. The new IEC 62368 standard is not only an update of the previous standards with a broader scope, but also includes a fundamental change from "prescriptive" to an HBSE (Hazard Based Safety Engineering) approach. This requires the manufacturer of the product to identify and classify potential hazards that may arise from energy sources, including electric shock, fire, chemical, mechanical, thermal and radiation hazards. (Table 2) These three classes broadly cover the protective measures to be applied. The extent and type of safety precautions also depend on the person who has access to the equipment and is classified as "layman", "instructed" or "qualified". However, a documented risk analysis of the use of a component certified to IEC 62368 in a potential application is not required, as is the case with medical standards such as IEC 60601-1.

Greater flexibility and easier handling

Although new terms and categories of hazards and users are introduced, IEC 62368 is intended to be better adapted to the new technologies. In fact, in some areas the requirements are less stringent than in IEC 60950; for example, to allow the use of Fully Insulated Wire (FIW) in transformers. As IEC 62368 is less prescriptive, it also offers more flexibility in achieving the appropriate level of safety for a particular application. However, manufacturers of equipment power supplies are finding that there is sometimes a requirement to assess and document the power supply in its particular application in terms of hazard in order to simplify certification for the end device. The only practical way to achieve this is through certification to the relevant application-specific standards. If the power supply is intended for general purpose and certified to IEC 62368-1, the cost of multiple certifications for all potential applications is high, which can ultimately lead to higher sales prices and delays in product launch.

The ZVEI (German Electrical and Electronic Manufacturers' Association) has published its guideline "Selection of safety standards for power supplies" with contributions from the European power supply manufacturer Recom, which discusses the expiry of EN 60950 and its possible successors. Some manufacturers are hoping that the increasing demands for certification in the future will make it easier to handle future standards that relate specifically to power supplies and are application-independent, such as IEC 61204 with reference to IEC 62477, IEC 60204-7 and IEC 61010-2 -206. However, it is possible that even with a future cross-application power supply standard, an application-specific standard and even IEC 60950 for export markets would still be necessary at the customer's request.

Difficulties with IEC 62368 worldwide

An additional difficulty with the transition to IEC 62368 is that it is not yet viable. The third edition of IEC/UL 62368-1 is due to be introduced on the day IEC 60950 and IEC 60065 are withdrawn. However, EN 62368-1 is still in its second edition. As this will also lose its validity on December 20, 2020, the third edition needs to be published soon, which is expected to happen in 2020. Delays in approval were due to the introduction of a new system of harmonized standards advisors (HAS), which had the task of improving the "quality and timely availability" of safety standards for the EU internal market.

Other countries such as the USA are pushing ahead with UL 62368 Edition 3, while Canada, China, Korea and Taiwan are pushing national variants. UL has also stated that they will continue to accept UL 60950 certificates for products already on the market after 2020 - provided there is no major revision. Europe, on the other hand, requires that all new product submissions as well as existing product certifications are adapted by the deadline of December 20, 2020.

A potentially unintended consequence of the IEC 62368 certification requirement is that the product must be specifically applicable for AV or consumer applications, even if it is intended for industrial use only. For shipments to China, this may result in the authorities then also requiring CCC certification for consumer products, even if the part is being shipped for industrial use. CCC certification is expensive, time consuming and can only be done in mainland China with full disclosure of valuable intellectual property, including design, PCB layouts and BOMs with the associated risks.

Precisely plan the changeover to IEC 62368

Planning the transition to IEC 62368 for suppliers of components and devices is an important task, not only for manufacturers of power supplies. Recom has already certified all its AC/DC products certified to EN/UL 60950 and EN/UL 60335 with EN/UL 62368 in parallel. Medically certified products (EN/UL 60601) are not affected by this, as they are not dependent on EN 60950 for CE marking.

Certified to various safety standards: The contact-cooled AC/DC power supply unit RACM-550. © Recom

Recom DC/DC products do not require safety certification. However, some product ranges have been voluntarily safety certified so that they can potentially be part of a safety isolation system. In these cases, new products are certified to IEC 62368 or IEC 61010 or have dual IEC 62368/IEC 60950 certification. For some existing high power series, IEC 62368 re-certification is carried out as a documentation change, but without design changes. For others, IEC 60950 certification is retained and valid applications where a defined level of insulation is required continue to apply. Some products will be phased out if the cost of re-certification is not viable.

The aim is to make it easier to navigate through the IEC 60950 & IEC 60065 "jungle" in future. But there are a few obstacles to overcome first. Companies should already be planning for the upcoming changes in detail, even if the publication of the 3rd edition of EN 62368-1, for example, is still a long way off. Suppliers such as Recom are helping by investing in the recertification of their products to IEC 62368. The technical sales team at distributor Schukat electronic also offers support for customers with queries about certifications and the upcoming change in standards, as well as design-in support for a possible change from an IEC 60950-certified product to an application-specific or IEC 62368-certified replacement.

The authors

Steve Roberts, Innovation Manager at Recom Power, and

Frank Stocker, Field Application Engineer Power Supplies at Schukat electronic