Requirements for PCB Component Replacements in an IEC 60601-1 Compliant Device

[nbarabino]

Hello

We have an IEC 60601-1 Third Edition compliant product (USB powered) which has to have one PCB mounted component replaced due to stock concerns. We have found a substitute with identical electrical function and package (DIP).

Is there any compliance test that has to be repeated? Upon our assesment there is nothing that may change the test results with the new component.

Thank you for your help

Regards
Nicol

 

[somashekar]

Welcome to the Cove Nicolas.

Just one question ...
Is that a safety critical component ?

 

[nbarabino]

Hi

Thanks for your answer.

In fact, no, it's a voltage regulator.

Regards

 

[somashekar]

Hi

Thanks for your answer.

In fact, no, it's a voltage regulator.

Regards

How would you say No.
Has your dFMEA assessed the failure modes of the voltage regulator and the effects thereoff.
Have you also consulted your test house ?

 

[nbarabino]

Hi, I'm sorry I should have given more details on the device.

I said no because the device has no patient connections (it's a wireless transmitter to communicate with an implantable device), an therefore the failure of the regulator may only have effect on the wireless link, which has been rated as not critical.

We haven't consulted yet our test house.

 

[somashekar]

Hi, I'm sorry I should have given more details on the device.

I said no because the device has no patient connections (it's a wireless transmitter to communicate with an implantable device), an therefore the failure of the regulator may only have effect on the wireless link, which has been rated as not critical.

We haven't consulted yet our test house.

If this determines performance of an implant device, then performance failure is safety critical to the patient. Under your circumstances, I would discuss at length with the test house.
Note: Are both the earlier device and the replaced device carry some sort of safety mark like the UL mark ? Has this been one of the requirements written in your design dossier.

 

[nbarabino]

I'm checking now, but I am pretty sure that the telemetry is not safety critical for the patient. In this case will still be needed to repeat tests?

Regarding UL mark: The new device has it, not the old one, and it was not on the requirements.

 

[Dimitri2]

Just if the telemetry would be safety critical, the whole thing would IMHO cramble down.
You can never rely on radio link for safety. And if you do... Well

So, I think you will not have to repeat tests. But you will have to explain in the risk assesment why you think it is not critical. Ask your auditing person (we have a company which visits us once a year just to confirm our overall certification). At the end, this company says to us if tests are sufficient and new are needed.

 

[Peter Selvey]

I think there may be a basic point of confusion here. For a medical device, just about every part is "safety critical" because it relates somehow to the function.

But, for product certification, they have a "scope of test" and/or scope of certification, which is usually far more narrow. For starters, in UL 60601 the scope is limited to direct hazards (see the definition of safety in the standard), which means cases where harm is caused by a physical "thing" coming out of the device such as electricity, heat, fire or mechanical movement. Indirect harm, such as failure to alarm or misdiagnosis are not covered (it is in the 3rd edition, but that's a different story).

Next, UL's product certification scope is further limited to "ELECTRICAL SHOCK, FIRE AND MECHANICAL HAZARDS ONLY" (have a look at your UL Online Certification, and click on the link "See General Information ... ").

So, while the part in question could be safety critical, it's not likely to be something UL is interested in. Keep in mind, just testing to UL 60601-1 itself is already a large amount of work, and certification agencies like UL don't really have the time, resources or expertise to be handling "safety" in the full regulatory context. They are interested in changes to parts which form part of electrical isolation barriers, limit fire, leakage current, over temperature and so on, i.e. direct hazards.

 

[nbarabino]

Thank you both.

I will further analyse the associated risk and let you know if retesting is needed.

Regards