Who compiles the Critical Component List, Insulation Diagram etc.?

S

sbp9674

Hello everyone. For 60601-1 approval, is Critical Component list compilation done as per Manufacturer's discretion (like BoM) or can the notified body insist on including more such components?

Case in point, we have submitted our device along with all necessary documentation to UL for 60601-1 approval. The docs included a CCL from our side (Manufacturer version). Now UL is insisting us to add things to that list that really don't have any safety related implications at all, e.g. PCB (the entire device is a 5V DC application plus probability of PCB "failing" is negligible). These changes will reduce flexibility of vendor choice in manufacturing, so its a pain for us.

As much as I understand, the 60601-1 standard does not even mention anything about "critical components". Would really appreciate if anyone can point out if UL is well within their rights to do so. How about insulation diagram, do they have any say in it too?

Thanks in advance!
 

Pads38

Moderator
Most test houses (not Notified Bodies) have a pre-conceived list of parts and components that they consider to be critical. The PCB (PWB) is included as the flammability ratings can be important.

To argue against this you will need to provide engineering proof as to why, in your application, this cannot be significant. I would suggest that you look at Clause 13.1.2 where there is a 'get out' clause for circuits that cannot supply more than 15W or 900J. (in single fault condition as well as normal condition).

Welcome to the forums!
 
S

sbp9674

Thank you Pads38!
Well we did bypass the enclosure fire safety requirements by invoking 13.1.2 (ours take <12W in SFC). However, the enclosure has been added back to CCL citing mechanical strength / integrity requirements, along with a bunch of other stuffs. Also, our PCB substrate is FR4 which has some UL94 rating. Problem is that present vendor and dimension details of the PCB/enclosure have also been added to the CCL, despite our protest. This makes it difficult to make even non-functional revisions in future (say PCB size) or change of vendor when scaling up volume.

This is the first product we are taking for 60601-1 approval so I'm not sure whether such unyielding attitude is expected on the test-house's part or are manufacturers allowed to negotiate. Is it a big deal if such deviations (vendor, size) happen between the report's CCL and running BoM's CCL?
 

Pads38

Moderator
I don't think that the listing of a component on the 'Critical' list necessarily prevents you from making changes in the future. And it would not automatically invalidate all of the testing.

If, for instance, you were to change the PCB (suppler or size/shape). The proposal to change would be captured by your Engineering Change process, which would then go on to analyse the implications of the proposed change. It would be at this point that you are compelled to show that the change would not influence safety requirements.

If your engineering evaluation was not able to clearly show that there was no safety implications to the change then you could go back to the test house, identify the change, and repeat the limited section of testing that might be influenced by the change.
 
S

sbp9674

Thank you Pads38. We've finally come to a middle ground. The critical components proposed by the test lab are still retained, but the vendor details are mentioned as interchangeable. As long as we maintain the same materials / safety parameters, we are free to do the design changes.
 
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