EBME Forums Forums Maintenance Technical Assistance Double insulation

We were recently doanted some Pari Junior Boy nebulisers (new and boxed), and upon inspection found that the live and neutral spade connectors inside the plastic case were not insulated. The device is CE marked to MDD and marked as double insulated. It seems to me that the only protective barrier against electric shock is the plastic case itself.

I made equiries of the MDA and was told the following:

"An air gap around conductive parts counts as insulation"!!

I can't see how an air gap could prevent electric shock in the single fault condition of a broken or damaged case.

Has anyone else experienced this with a medical device? All other classII devices I have seen have at least got protective boots over the spade connectors.

We noticed this deficiency with the Pari nebulisers about 4 years ago and reported it to the company, clearly to no avail. The MDA response is priceless, I sometimes wonder if some of these people have ever taken the covers of a piece of medical equipment - they sure can't have ever received an electric shock!

We rejected the Pari nebulisers a few years ago - but then ended up with some being donated to our childrens unit ! Perhaps charities are the only people who will buy them ! ?
It's ridiculous to suggest that an air gap can act as secondary insulation. A child poking Daddy's metal comb or biro through the casing would argue the point quite well. How can this stuff get a CE mark ????

I'd get back onto the MDA and ask to speak to someone a little more knowledgeable.

I've now been in touch with the 'electronics expert' at the MDA and he advises me that a broken case does not constitute a single fault condition. The requirement is for the insulation (reinforced insulation in this case) to provide the equivalent level of electrical isolation of two layers (hence the term double insulation). Clearly, this is of little use in the real world where equipment is regularly smashed to bits! The internal wiring must simply be secured such that if a connector became detached, the wire could not touch any exposed conductive part. It was pointed out to me that you wouldn't expect the soldered connection of a mains wire on a PCB to be separately insulated - fair point perhaps?

Unfortunately it seems that the equipment meets the standards, despite being a potential hazard. So much for standards huh!?

Apollo
I would have have a word with your procurement manager and ask for all purchases to be blocked until you are happy that the company have taken your very sensible sugestion seriously and done something about it.

I posted the above , not Lee. He hadn't logged out/I didn't log in.