Connection to a generic separate power supply

[Roland chung]

Hello everyone,

The clause 8.2.1 of 60601-1 3.1ed states that if a generic separate power supply is specified, then the specification in the accompanying documents is inspected.

Normally, the generic separate power supply doesn't provide with the medical device. It seems that the safety is guaranteed by the user manual only. But, the effectiveness of manual (as a risk control measures) is very weak, especially considering the reasonably foreseeable misuse. It is expected that 60950 grade, or worse power supplies (e.g. knockoff) may be used where 2 MOPP is required, especially for home-use devices (e.g. stimulators). So should 2 MOPP isolation be designed in the medical device when it is intended to be used with a generic sepatate power supply?

Could you please shed some light on this?

Thanks,
Roland

 

[Stijloor]

A Quick Bump!

Can someone help?

Thank you very much!

 

[Pads38]

Hi Roland,

I think you have basically answered your own question. You have identified, by Risk Management, that using a "not controlled" power supply is reasonably foreseeable misuse, and the probability of such misuse is quite high.

So, if you cannot rely upon 2 MOPP in the PSU then you will need to provide it elsewhere, although you may be able to say that the PSU provides 1 MOPP.

 

[Roland chung]

Thank you for your input.

The same question I also asked expert of IEC working group, the answer was that where a generic supply is used It must meet (at minimum) 60950-1 (and that must be required by the instructions). 60601-1 is based on normal use which by definition is as instructed in the IFU. If we assume no one reads or pays attention to the instructions devices are impossible to make safe!

Regards,
Roland

 

[Pads38]

My concern with this is it might say it complies with 60950 but can you be sure?

There are so many bad copies of phone / computer chargers, and so many stories of fires being started by them.

To avoid that when we did a device with a "plug top" PSU we used a different connector to enforce the "only use our PSU" rule.

 

[antonoia]

Hello Roland,
clause 7.2.5 gives some options to escape..one is to apply some marking on your connector as risk control.
Second option, you can limit the range of the power supplies that can be used giving details and specification of models and brands that you trust and for what is proved your device complies with the standard. Looking for other comments.. regards!