Defining a lower ESD test level in IEC 60601 safety test

[AlexM]

We are facing a major ESD test challenge with integrating a high-quality image sensor into a class-2 product. We spent 5 months changing our optical and mechanical designs without getting to the required test levels thus far. We can not mechanically block the optical path due to the loss of video quality, and we can only get about +/-6KV with thin transparent windows. If the product remains safe, and it does not cause any harm to the patient or operators, can the manufacture of a class-2 medical device define a lower ESD test level for a sensitive imaging sensor that can not pass +/-8KV or +/-15KV static discharge? Is this managed in the risk management document? Should there be a specific instruction for the certified test labs to exclude a specific area during the 60601 ESD test? If this is permitted, does this need special labeling?

 

[Peter Selvey]

It's not unusual to need reduced levels for immunity due to the medical device technology. It's well covered in the standard. Do you have a copy?

 

[AlexM]

Thank you Peter! I have an old copy of 60601-1:2005. Is there a particular chapter and section that I should be looking into? Thanks, Alex

 

[Jaydub]

There is a clause in the ESD standard (IEC 61000-4-2:2008, 8.3.2e) which says that connector contacts or other accessible parts that are ESD sensitive because of functional reasons and are provided with an ESD warning label, may be excluded. You would also need something in your documentation about any special ESD mitigation procedures.

 

[Peter Selvey]

FYI The detail is IEC 60601-1-2 (just for EMI/EMC), not IEC 60601-1.

It's a bit annoying as the EMC standards are expensive, and most of the detail is there for the test labs. But medical device manufacturer still needs to have the standard as there are requirements for the instructions for use, test planning, risk management and so on that feed into/from the tests. And of course in this case, the structure on how to justify, arrange and disclose any modified test levels.

 

[AlexM]

Thank you for your inputs! This is very useful. I will look into the option of adding a label to the product and writing a warning in the instructions.