We are making a product -a warning light- with 220V rated voltage. The product has a non isolated offline buck regulator. The 220V part can be accessed without the use of a special tool (there is a "turn to open" type cover). Moreover, there are parts on the same side of mains voltage which are used for adjustment of unit (buttons and trimpots).

I think that this product is unsafe, therefore not compliant to LVD. I want to persuade my boss that the design needs to be changed for compliance.

1) Are my concerns rightful?

2) Is there a standard/document which is generally about electrical safety in electronic products, which will solidly support my concerns:

  • mains voltage parts should not be accessible to end user
  • non isolated regulator creates a safety risk

Or let's ask with a different perspective; let's say that someone is checking the product for CE compliance. How will he decide that the product is unsafe? Will he rely on a document or just say "hey this is obviously wrong, someone can get shocked"?

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    \$\begingroup\$ Yes, most likely unsafe. You can look into UL60950. I'm sure you can find a copy of it online. Non-isolated supplies are not inherently dangerous, but you will need to be able to prove that any single component fault will not put mains voltage on the output. If you send this to CE, UL, TUV etc, they will perform those single component faults and essentially make sure the product fails safely. They will check the spacing between your mains input and "safe" output. There is even a "finger" test will a metal hand that makes sure you can't shock yourself (which it sounds like you'll fail). \$\endgroup\$ – Stiddily May 29 at 12:20
  • \$\begingroup\$ @Stiddily I am currently trying to find safety standards, found this: books.google.com.tr/… On 7.9.2 - Protection against indirect contact, the book describes the measures needed for protection. I believe the non isolated buck regulator doesn't utilize any of these. \$\endgroup\$ – C K May 29 at 12:54
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    \$\begingroup\$ For Europe, the product needs to be CE marked in compliance with the Low-voltage Directive 2014/35/EU. The directive itself doesn't contain much in the way of helpful text, but points at a a vast array of standards. I believe the applicable one is the family of standards below EN 60950 regarding electrical safety. I can't find the exact part or I'd post an answer, but somewhere in there, you'll likely find a requirement stating a necessary first digit of IP class (ingress protection), 1 to 6. The IP class itself is defined in IEC 60529. \$\endgroup\$ – Lundin Jun 4 at 7:50
  • \$\begingroup\$ @Lundin yes, I found some standards relevant, but forgot to edit the post. If I recognize correctly, the mains voltage part should be rated IP2X to prevent any finger touch. I will answer the question soon, sorry for taking your time. \$\endgroup\$ – C K Jun 4 at 8:35
  • \$\begingroup\$ It's a very good question btw - basically everyone designing products for 230VAC will have the same question. However, LVD only applies to Europe + countries that accept EU directives. UL for other countries might have entirely different requirements. \$\endgroup\$ – Lundin Jun 4 at 10:35

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