Change Now – to the EN 62368-1 Compliant Power Supply
Schukat explains the new power-supply sector safety stand
On 20 December 2020, the EN 60950-1 safety standard for IT equipment, binding across Europe, will expire. This is because the existing standard is to be replaced by new national safety standards based on the international IEC 62368-1 standard. What do users now have to be aware of?
When does the new standard come into force?
The old standard will be replaced by the 3rd edition of EN 62368-1, which will be published in 2020 and come into force on 20 December, 2020.
Why does the new standard exist?
Not only because of the DOW (Date Of Withdrawal) of the old EN 60950-1, but also because the existing 2nd edition of EN 62368-1 is set to expire on December 20th. In addition, with EN 62368-1, the responsible sections of UL also plan to declare the 3rd edition of UL 62368-1 to be a binding standard.
What issues is this going to create?
The replacement of EN 60950-1 is of major relevance, and not only for IT equipment. Over the years – due to the lack of a "suitable general power supply standard" – the international IEC standard and its national offshoots EN 60950-1 and UL 60950-1 have evolved to become a standard also applicable to power supply products. Many AC/DC power supplies and DC/DC converters have been designed and certified in line with the specifications of the standard.
Schukat does indeed offer power supply products that are certified according to EN 60950-1 and other safety standards. Nevertheless, manufacturers are tending mainly toward the new EN 62368-1, which is seen as the direct successor to EN 60950-1 and as a cross-application standard that also applies to switching power supplies.
Innovations of EN 62368-1 compared to the old EN 60950-1
Completely different structure founded on the Hazard Based Safety Engineering approach (HBSE, control of determination of product safety lies with the manufacturer).
• Describes protective safeguards based on a three-block model, taking into account possible energy sources.
• Protects users (divided into ''ordinary persons'', ''instructed persons'' and ''skilled persons'') by identifying hazards and the transmission path to the user and prescribes appropriate safeguards.
• According to the HBSE approach, risk assessment of potential hazards stemming from energy sources must be taken into account.
• Considers various forms of energy (divided into three classes according to strength) and their effect on the body and on flammable materials.
- Electrical energy (ES)
- Power sources (PS)
- Kinetic energy (MS)
- Thermal energy (TS)
- Radiant energ (RS)
• Also considers chemical reactions, but without classification.
A power supply example
Because the electrical power source is divided into classes ES1, ES2 and ES3, an appropriate safeguard must be selected depending on the particular strength involved. For a power supply, a safeguard might be:
- Basic insulation
- Additional insulation
- Reinforced insulation
The lower the ES category of the power supply, the lower the effort and expense that needs to be taken into consideration for protection at the system level. With the new approach, the familiar SELV (Safety Extra Low Voltage) definition is no longer applicable to the electrical power source – this is now equivalent to the ES1 category. Likewise, the old definition of LPS (Limited Power Source) according to UL 60950-1 now passes to the definition ''Power Source <PS 2.''
Why should I already be looking at the change of standards?
The power supply, as an assembly that forms part of the overall system, is a key part of the safety certification of the end product. Currently, power supplies can be obtained that have been certified according to EN 62368-1; as a combination of EN 62368-1 and EN 60950-1; or exclusively according to the old EN 60950-1.
From December 2020, the old EN 60950-1 will no longer provide a presumption of conformity for CE marking. Products that are only EN 60950-1 compliant may not be imported into the EU after the deadline. (Until now, the second edition of EN 62368-1 still allows the use of EN 60950-1 compliant modules – such as switching power supplies – if they are installed in an end system)
According to the DKE (the German Commission for Electrical, Electronic & Information Technologies), the clause from the second edition of EN 62368-1:2014 + AC:2015 that reads ''Assemblies that meet the requirements of IEC 60950-1 are permissible for equipment in accordance with this standard without further assessment, provided that the use of the assembly in the end product is taken into account'' will continue to apply with the publication of the third edition. This means that, for the time being, switching power supplies already on the market will not lose their CE marking and may continue to be installed in end systems tested in accordance with EN 62368-1.
With the 4th edition, not to be published before the end of 2021, this clause will also finally be deleted from EN 62368-1.
• The impending discontinuation of the 60950-1 standard has spurred several power supply manufacturers to streamline their product portfolio. In many cases, power supplies with older circuit topologies and those for which successor products offer significantly better performance are no longer certified according to the new standard and will be discontinued during the course of the year.
• Products supplied by Schukat are also affected. For all discontinued products, Schukat already has EN 62368-1 compliant alternatives in stock.
• Ongoing very long – and potentially increasing – lead times for the necessary re-certification processes of plants and systems + increased workload for accredited bodies.
• Falling freely available stocks.
• Information about alternative products as well as stimulus for approval processes and certifications urgently required.
Assistance from Schukat’s technical sales team
We are more than happy to support you in selecting a suitable replacement article. Please contact your responsible Schukat customer advisor
In order to simplify the selection of MEAN WELL switching power supplies that comply with the new standard EN 62368 and so that you can compare and check the technical information quickly and easily, we have prepared a cross-reference list for you: