Author:
Jeff Schnabel, VP of Marketing, CUI and Simon Duggleby, Mouser Electronics
Date
09/03/2019
PDF
Click image to enlarge
Figure 1: The HBSE three-block models.
IEC 62368-1-based standards will soon be replacing a number of existing safety standards for IT, communication and audio-visual equipment. And in a move that’s proved a significant boon to product vendors with global customer bases, the US and EU regulators have aligned the date when the new standards replace the ones based on IEC 60950-1 and IEC 60065. The day to mark on your calendar is December 20, 2020, which gives you a single point in time to work toward when it comes to regulatory compliance in these two major markets.
This alignment came about when the EU extended the date for “cessation of presumption of conformity” for products that were already shown to conform with the outgoing EN 60065 and EN 60950-1 standards. Although neither was due to be withdrawn until December 2020, the cessation date was originally June 20, 2019. But with the two dates now aligned, there will be no need for special exceptions to be made by the EU.
Clarity
For product makers, the situation is now crystal clear. December 20, 2020 will see the old standards withdrawn, and any device that’s in scope of EN 62368-1 (the IEC standard as it’s been written into law in the EU) must be tested in line with the new standard.
The US-based UL certification organization has also confirmed it will shift the date when UL 62368-1 (the US version of the standard) supersedes both UL 60065 and UL 60950-1, from June 20, 2019 to December 20, 2020.
So whichever side of the Atlantic your markets are, this is now the date when things change. And thanks to this regulatory alignment, you’ve got a bit more time to implement your new testing procedures and documentation.
HBSE: A New Approach to Safety
The reason for introducing 62368-1 is down to the increasingly blurred line between AV equipment that would fall under 60065 and IT equipment covered by 60950-1. However, IEC 62368-1 doesn’t simply bring together the standards it’s replacing. While the scope may be the same, the TC108 technical committee at the IEC responsible for 62368-1 has used the so-called “hazard-based safety engineering” (HBSE) approach to create it. HBSE aims to produce a standard that’s less prescriptive, more future-proof and ultimately helps make products safer for those using them.
HBSE has been formalized over the past two decades, with the IEC showing its commitment to the approach since at least 2002, when it passed the then-new ECMA-287 Safety of Electronic Equipment standard to the Hazard-Based Standard Development Team in TC108.
The HBSE approach moves focus away from needing to demonstrate that a product meets prescribed specifications. Instead, product manufacturers must show that known hazards have been thought about, and that the product is designed to be safe to use in the anticipated context(s). Although standards including 62368-1 are hazard-based, they don’t require risk management in the same way as standards such as IEC 60601-1.
How HBSE Works
The HBSE principles seek to safeguard those using a piece of equipment, in both normal and fault conditions. First, you identify energy sources that pose a potential risk, and the means by which this energy could transfer to the user. Second, you pinpoint ways to prevent this transfer from happening and put suitable safeguards in place to protect the user and/or surrounding property against injury or damage caused by electric shocks, thermal burns and other hazards. Crucially, HBSE measures how effective these safeguards are, as well.
The analysis of hazards and safeguards is done using so-called three-block models, shown below, with the safeguard put in place to prevent the transfer of energy from the source to the body part.
The 62368-1 standard divides the energy levels to which a user or property could be exposed into three categories. Class 1 is the lowest, and Class 3 the highest. These are shown in the table below.
Click image to enlarge
The different classes of energy help engineers design in appropriate safeguards. Again, the 62368-1 standard has different levels of safeguard: basic, supplementary and reinforced.
It also sets out three different levels of user competence: Ordinary Person (equivalent to User/Operator in 60065/60950-1), Skilled Person (equivalent to Service Person) and an additional level, Instructed Person, which is someone who will be supervised by a Skilled Person, or has been trained by one.
These various hierarchies all interact, of course. For example, to protect an Ordinary Person from a Class-3 energy source, you will require either a reinforced safeguard or a double safeguard.
Complete Compliance: Products, Components and Subsystems
Designers need to remember that the new standards apply to both their complete end product and its major subsystems and components, such as power supplies. Currently, you can source power supplies certified to one of 62368-1, 60065 or 60950-1. IEC 62368-1 includes a clause (4.1.1) that allows for power supplies certified to 60950-1 or 60065 to be used in end products tested in line with 62368-1. It also allows for 62368-1-certified power supplies to be used in 60950-1- or 60065-compliant end products. That said, this clause may not remain after December 20, 2020 in the EU.
With this uncertainty over whether legacy 60950-1 or 60065 approvals will still be valid in the EU, equipment makers, including CUI, are currently transitioning their power supply portfolios to the latest 62368-1 second-edition standard. This will benefit customers who use these components in products sold globally, by minimizing the need for re-testing when the changeover day comes around.
Conclusion
The new, hazard-based 62368-1 standards have already been adopted in Europe, the USA and Canada. And while the older standards aren’t being withdrawn until the end of 2020, smart equipment manufacturers are busy testing their new and existing products in line with the new standards today. This is the best way to ensure they have no hiccups when the old standards are retired.
The 62368-1 standard aims to provide designers with greater flexibility by being less prescriptive, while ensuring users benefit from safer products. But the switch to HBSE also represents a major shift in approach. For equipment designers and manufacturers, this means there’s plenty of information to read through and understand, if they’re to ensure their products are compliant. The extension of the original June 2019 deadline provides additional time to prepare, but it also means there will be a hard cut-off for the legacy standards. If you haven’t already, now is the time to start this process.
Mouser Electronics
CUI Inc
