EBME Forums Forums Management Medical Equipment Management No more PAT testing of medical equipment!

The problem with an IT supply is there is no reference of the mains supply to earth, therefore the applied test voltage (the mains) would not be the full amount. The higher the earth-neutral voltage the less accurate the leakage readings will be. In other words the direct (like 60601) and differential methods need a TN-S supply to give accurate readings. (The N-E voltage should be less than about 7V.)

The differential method is safer for those performing any tests, including anyone else who may be contacting the equipment (or a connected peripheral), as the earth connection is never broken. This is also ideal for items that are allowed a higher equipment leakage current, such as mobile x-ray units (2mA rather than 0.5mA).

The Alternative method is especially useful where a device is PC based so needs a long time to boot up and shut down between test, such as many ultrasound units. No boot up and down required, no switching of mains polarity, no messing around. The measured value will be almost identical as an open neutral 60601-1 test, which is why the limit is 1mA rather than 0.5mA. This is the real time and therefore money saver!

Yes, your last point (especially) is a good one.

Although it could be argued that "real" electro-medical equipment has no business being in an "IT" (that is, non-medical) ("floating earth", or whatever) environment in the first place! I wonder what the manufacturers' documentation - not to mention legal teams - have to say about all that?

But I can feel another box on the test sheet (or field in the database) coming on:- one that says which test to use (for each piece of kit).

Otherwise, each time the tech comes along to carry out his annual (whenever) EST, any hoped-for time saving is likely to be negated by him puzzling out which test method to go for!

Once again the need for good record keeping is emphasized; as in:- "what did we do last time"?

Leakage current test methods:- Rigel .pdf.

Vignesh,
I have deleted one of your posts before as it was an advert for your equipment.
Please do not post adverts again or you will be blocked from this site.
RoJo

Hi Mike X,
Equipment (X-ray, ultrasound and laser therapy), type tested to 60601, but used in the veterinary sector, can anybody confirm or guide me to where the guidance is for vet market. I personally believe that if the equipment has been type tested to 60601, then it should be tested to to the 62353 standard throughout it's life irrespective of where it is used.

Thoughts please.

Many thanks in advance.

Hi Winston,

It makes no difference that the medical electrical equipment is being used in the veterinary sector. BS EN 62353 (IEC 62353) scope includes all ME Equipment and ME Systems, which comply with IEC 60601-1.

As far as I know all medical electrical equipment used by vets will conform to the medical device directive (now medical device regulations) and will meet IEC 60601-1. Therefore it should be tested following 62353.

The IET Code of Practice for In-Service Testing and Inspection of Electrical Equipment specifically excludes such medical electrical equipment from its scope and refers you to BS EN 62353.

Hope this helps.

Mike.

Hello Winston

I'm wondering why you had any doubt about this (why you would have thought otherwise); has some "expert" been giving you "duff gen"?