The safety standard landscape after ‘60950’
2020/11/02
Many engineers have literally grown up with the 60950 safety standard as a backdrop to their career, either as designers of IT power supplies and systems or users of IT equipment. The standard dates way back to 1986 in its first incarnation as IEC 950, entitled ‘Safety of information technology equipment including electrical business equipment’. It was adopted as a CENELEC standard EN 60950 in 1988 and by UL as UL standard 1950 in 1989, to replace UL 478. UL later brought its numbering into line with CENELEC in 2000 with UL 60950 and approval agencies round the world have referenced the standard ever since.
60950 and its national versions came to be used as a default safety standard for many types of electronic and electrical equipment whenever there wasn’t an obvious product-specific standard, although it was originally intended for just IT and office equipment. For this reason, it also became the accepted international safety standard for AC/DC power supplies and DC/DC converters.
The landscape of electronic equipment has changed however, with the differences between IT and other electronic equipment becoming less defined. For example, there is a separate IEC standard for audio/visual equipment, IEC 60065, and one for household appliances IEC 60335-1, but is a ‘smart’ TV with Wi-Fi connection and integrated web browser an IT, an audio/visual or a household appliance?
The answer to this uncertainty is the ‘new’ standard UL/IEC/EN 62368-1, (although IEC62368 was first released in 2010), which will supersede both IEC/EN 60065 and IEC/EN 60950-1 on the 20th December 2020. It is unsurprisingly titled ‘Audio/video, information and communication technology equipment’ and will be a ‘catch-all’ for many products as they become increasingly internet-connected, whether used domestically, industrially or in business environments. Only specialist equipment such as industrial motor drives, medical, rail and professional test equipment which used to refer back to 60950 will still retain alternative standards to UL/IEC/EN 62368 for their specific application areas.
The old 60950 standard is prescriptive in nature, setting down design rules for insulation materials and safety spacing’s and setting AC mains over-voltage levels, for example, irrespective as to how the product would be used in practice. However, 62368 reflects the trend towards ‘hazard-based’ rather than ‘prescriptive’ safety standards. This requires product designers to take a more proactive approach using Hazard-Based Safety Engineering (HBSE) principles, effectively obliging the designers to consider and mitigate potential hazards that might arise from the use of the equipment in the end application. For this reason, not only is 62368 an alternative to 60950, but also a replacement as 60950 is being withdrawn and will cease to be accepted as a basis for CE marking after 20/12/2020.
Not all IEC member countries have adopted IEC 62368 yet and there is a possibility that dual certification with IEC 60950 and IEC 62368 will be necessary in these locations. Also, some applications can use alternate harmonized standards in order to justify their CE marking, so there is still some confusion in the market. The German organization ZVEI has released a guidebook to help on the selection of appropriate safety standards for power supplies which is available in English and German on their website or by below link (RECOM assisted in compiling this guide, along with many other leading German power supply manufacturers).
To a certain extent, the same concept is also being applied to the EMC standards. As IEC 60950 is primarily an IT standard, the matching EN 55022/55024 (CISPR 22/24) pair of standards were sufficient for almost all applications. Now IEC 60950 is being withdrawn, so other EMC standards come into play. Adding to the confusion, EN 55022 has already been superseded by EN 55032 (the limits stay the same) and EN 55024 has been superseded as well by EN 55035 (here the test methodology has changed, but the limits are broadly the same). For Household applications, a different set of EMC standards are used: EN 55014-1 and EN 55014-2.
Finally, complicating things further, UL, IEEE and CENELEC have a policy of doing major upgrades to every standard every few years to keep them ‘fit for purpose’. Although the existing UL 62368-1, IEC 62368-1, and EN IEC 62368-1 3rd edition standards have already been published, the EU Official Journal (OJ) currently only lists the EN 62368-1:2014 (based on IEC 62368-1 second edition) as a harmonized standard for CE Marking according to the Low Voltage Directive, and the EN 62368-1:2014+A11:2017 (based on IEC 62368-1 2nd Ed. as well) will probably be listed in the OJ by 20 Dec. 2020.
There are several technical working groups and HAS consultants working hard on a new EN 62368-1 (based on IEC 62368-1 3rd edition) version, but it will not be published in the OJ before sometime in late 2021, or even beginning of 2022.This means that there is a gap in the EU certifications landscape: the old standard is being withdrawn (EN 60950-1), the official replacements (EN 62368-1:2014 and EN 62368-1:2014+A11:2017) are still based on IEC 62368-1 2nd edition and will be withdrawn 6 Jan. 2023, but the most up-to-date EN 62368-1 version (based on IEC 62368-1 3rd edition) is not yet listed.
As the international standard IEC 62368-1 third edition has already been published and 3rd Ed. certificates and CB-reports are available from test houses, the existing IEC 62368 Edition 2 version will only remain valid until 20 Dec. 2020, the same date as the withdrawal of IEC 60950. Nevertheless there are still more countries listed with national differences for IEC 62368-1 2nd edition than compared to IEC 62368-1 3rd edition and finished CB certificates and test reports covering IEC 62368-1 2nd edition will still be valid after 20 Dec. 2020. Moreover, as general rule, CB certificates do not have a valid until date. Additional, the new EN 62368-1:2014 and EN 62368-1:2014+A11:2017 (both based on IEC 62368-1 2nd edition) and the new IEC 62368-1 2nd edition include a clause 4.1.1 regarding use of components which comply with IEC 60950-1 to be used in end-applications, even after 20 Dec. 2020.
UL has set no date of withdrawal for existing UL 62368-1 2nd edition, but all new RECOM products will be tested and certified to UL 62368-1 3rd edition.
Additionally, as with the EN 62368-1, UL 62368-1 2nd edition allows the use of UL 60950-1 components to be used in end-applications (“grandfathering” scheme).
This all means there are still several possibilities for certifications of RECOM products:
The table below shows the standards landscape at the moment.
Figure: Standards
RECOM: We Power your Products
The landscape of electronic equipment has changed however, with the differences between IT and other electronic equipment becoming less defined. For example, there is a separate IEC standard for audio/visual equipment, IEC 60065, and one for household appliances IEC 60335-1, but is a ‘smart’ TV with Wi-Fi connection and integrated web browser an IT, an audio/visual or a household appliance?
The answer to this uncertainty is the ‘new’ standard UL/IEC/EN 62368-1, (although IEC62368 was first released in 2010), which will supersede both IEC/EN 60065 and IEC/EN 60950-1 on the 20th December 2020. It is unsurprisingly titled ‘Audio/video, information and communication technology equipment’ and will be a ‘catch-all’ for many products as they become increasingly internet-connected, whether used domestically, industrially or in business environments. Only specialist equipment such as industrial motor drives, medical, rail and professional test equipment which used to refer back to 60950 will still retain alternative standards to UL/IEC/EN 62368 for their specific application areas.
The old 60950 standard is prescriptive in nature, setting down design rules for insulation materials and safety spacing’s and setting AC mains over-voltage levels, for example, irrespective as to how the product would be used in practice. However, 62368 reflects the trend towards ‘hazard-based’ rather than ‘prescriptive’ safety standards. This requires product designers to take a more proactive approach using Hazard-Based Safety Engineering (HBSE) principles, effectively obliging the designers to consider and mitigate potential hazards that might arise from the use of the equipment in the end application. For this reason, not only is 62368 an alternative to 60950, but also a replacement as 60950 is being withdrawn and will cease to be accepted as a basis for CE marking after 20/12/2020.
Not all IEC member countries have adopted IEC 62368 yet and there is a possibility that dual certification with IEC 60950 and IEC 62368 will be necessary in these locations. Also, some applications can use alternate harmonized standards in order to justify their CE marking, so there is still some confusion in the market. The German organization ZVEI has released a guidebook to help on the selection of appropriate safety standards for power supplies which is available in English and German on their website or by below link (RECOM assisted in compiling this guide, along with many other leading German power supply manufacturers).
To a certain extent, the same concept is also being applied to the EMC standards. As IEC 60950 is primarily an IT standard, the matching EN 55022/55024 (CISPR 22/24) pair of standards were sufficient for almost all applications. Now IEC 60950 is being withdrawn, so other EMC standards come into play. Adding to the confusion, EN 55022 has already been superseded by EN 55032 (the limits stay the same) and EN 55024 has been superseded as well by EN 55035 (here the test methodology has changed, but the limits are broadly the same). For Household applications, a different set of EMC standards are used: EN 55014-1 and EN 55014-2.
Finally, complicating things further, UL, IEEE and CENELEC have a policy of doing major upgrades to every standard every few years to keep them ‘fit for purpose’. Although the existing UL 62368-1, IEC 62368-1, and EN IEC 62368-1 3rd edition standards have already been published, the EU Official Journal (OJ) currently only lists the EN 62368-1:2014 (based on IEC 62368-1 second edition) as a harmonized standard for CE Marking according to the Low Voltage Directive, and the EN 62368-1:2014+A11:2017 (based on IEC 62368-1 2nd Ed. as well) will probably be listed in the OJ by 20 Dec. 2020.
There are several technical working groups and HAS consultants working hard on a new EN 62368-1 (based on IEC 62368-1 3rd edition) version, but it will not be published in the OJ before sometime in late 2021, or even beginning of 2022.This means that there is a gap in the EU certifications landscape: the old standard is being withdrawn (EN 60950-1), the official replacements (EN 62368-1:2014 and EN 62368-1:2014+A11:2017) are still based on IEC 62368-1 2nd edition and will be withdrawn 6 Jan. 2023, but the most up-to-date EN 62368-1 version (based on IEC 62368-1 3rd edition) is not yet listed.
As the international standard IEC 62368-1 third edition has already been published and 3rd Ed. certificates and CB-reports are available from test houses, the existing IEC 62368 Edition 2 version will only remain valid until 20 Dec. 2020, the same date as the withdrawal of IEC 60950. Nevertheless there are still more countries listed with national differences for IEC 62368-1 2nd edition than compared to IEC 62368-1 3rd edition and finished CB certificates and test reports covering IEC 62368-1 2nd edition will still be valid after 20 Dec. 2020. Moreover, as general rule, CB certificates do not have a valid until date. Additional, the new EN 62368-1:2014 and EN 62368-1:2014+A11:2017 (both based on IEC 62368-1 2nd edition) and the new IEC 62368-1 2nd edition include a clause 4.1.1 regarding use of components which comply with IEC 60950-1 to be used in end-applications, even after 20 Dec. 2020.
UL has set no date of withdrawal for existing UL 62368-1 2nd edition, but all new RECOM products will be tested and certified to UL 62368-1 3rd edition.
Additionally, as with the EN 62368-1, UL 62368-1 2nd edition allows the use of UL 60950-1 components to be used in end-applications (“grandfathering” scheme).
This all means there are still several possibilities for certifications of RECOM products:
- Finished UL certifications can either keep existing UL 60950-1 or get update to either UL 62368-1 2nd or 3rd edition. New RECOM products of course will only be certified to UL 62368-1 3rd edition.
- Finished CB certifications with IEC 60950-1 and IEC 62368-1 2nd edition will stay valid and do not necessarily need updates. New RECOM products will be certified to IEC 62368-1 3rd edition (assuming most countries update their national differences to this edition), otherwise IEC 62368-1 2nd edition may also be an option for required countries not adopting to IEC 62368-1 3rd edition after 20 Dec. 2020.
- Existing RECOM products without CE mark (DC/DC converters <75VDC) and with IEC 60950-1 and EN 60950-1 certifications can either be updated to IEC 62368-1 and EN 62368-1 or just keep the IEC 60950-1 for end-applications considering clause 4.1.1 of IEC 62368-1 and EN 62368-1. New DC/DC converters will be certified to EN 62368-1:2014+A11:2017 or even to the newer EN IEC 62368-1:2020+A11:2020 3rd edition (no need to consider list of harmonized standards).
- Existing RECOM products with CE mark (DC/DC converters >75VDC and AC/DC converters) and with IEC 60950-1 and EN 60950-1 certifications can either be updated to EN 62368-1:2014+A11:2017 or keep the IEC 60950-1 for end-applications considering clause 4.1.1 of EN 62368-1. Of course only together with reference to a RECOM rationale document regarding safety for intended use as built-in component, updated risk assessment and updated CE declaration referring to company standard instead of EN 60950-1. New CE products will be certified to EN 62368-1:2014+A11:2017 (assumed this version will be added to the list of harmonized standards with 20 Dec. 2020).
The table below shows the standards landscape at the moment.
Figure: Standards
RECOM: We Power your Products
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