EBME Forums Forums Maintenance Technical Assistance Acceptance testing

I think you are right, but feel the MHRA should contact them not individual Hospitals. As a more definintive answer is required.

Classifying the device as Class I electrical, Class II medical has really set the cat amongst the pigeons and hence the confusion.

However what do you do in the meantime? reject the units outright or test them to Class II CF and wait for clarification.

To reject them outright would certainly spur Critcare into action but cause delays to the medical staff who just want to use them.

I will flag this issue again with our department head who used to work for the MHRA and see if he can take it forward. When I raised the issue initially with him, he made the final call on the products acceptance within the trust.

I see what you're getting at although I disagree that EST to Class 2 is acceptable when testing Class 1. Any of us, as technical representatives of the purchaser, are entitled to contact MHRA or manufacturers if we have a valid concern RE: technical or clinically related technical issues. MHRA don't know about these issues until we or the manufacturer contacts them - or there's an incident logged by the operators.

Check the PPQ for class designation, I assume class 1.

I would personally reject them and inform finance to stop payment.

Give the manufacturers 30 days to make an appropriate response rather than speculation and give them the opportunity to modify the devices if it is both appropriate and a certified modification (device has to be re-certified CE).

If they dont then they loose the business and I'm sure there are cost effective solutions other than that particular model.

That way, the manufacturers are running around rather than us poor hardworking EBME guys.

I took this issue up with Richard Mellish at the (then) MDA in early 2002 following receipt of two Tyco patient warmers which, at the time, were Class 1 items with no external accessible earthed parts whatever. Subsequently Tyco were considerate enough to begin fitting earthed studs to the units as an aid to hospital technicians.

Mr Mellish was and may still be chairman of the BSI commitee that drew up IEC60601-1. He was emphatic that provided internal clearances are OK no externally earthed testing point is required.

I was advised to open the case and look inside for a marked accessible earthing point to do tests to. If there wasn't one that WOULD be an issue.

I pointed out that:
(a) As best practice, tests must be completed upon closure of a case. Therefore closing the case after such a test would neccesitate a re-test.
(b) Given that we test thousands of items a year opening cases to perform such tests routinely would carry a small but in my opinion needless risk of human error with uncertain consequences.

His response was that our technicians should be sufficiently competent to remove half a dozen screws, attach an earth bonding lead to an internal test point, test the item, then close the case afterwards without incident.

Mr Mellish is undoubtedly very eminent but the practicalities of modern NHS work on the conveyor belt are that you ELIMINATE any risks you can. I eliminated that one by barring purchases of such items. That's my advice to anyone confronted by that situation.

Stuff like this will make a tremendous dent in the efficiency of departments and their ability to cover equipment adequately. Imagine the effect if 20% of your stock requires case opening to effect a simple and what would have been quick safety test!

As regards acceptance, since it can't pass to Class 1 and shouldn't be tested to Class 2 since that test is inadequate for the purpose FAIL IT.

Marc

Hi Marcel,

I disagree - it shouldn't be failed on grounds of safety since, adhering to the standards, it may meet and exceed the requirements of the standard if not the spirit of it (the intended purpose of the clause or sub-clause). To argue might be very difficult if not impossible.

What I do agree with you on is that as purchasers we are in a position choose whether a product meets our needs and if it doesn't to reject it. Clinical and technical evaluation prior to purchase is probably the best way forward.

Hi Marcel

Another point to what you are saying is that by opening the case, you can be negating the warrenty.

The only way that we can see round it, is to attach a extra lead to the mains input with an exposed earth. Therefore you can test as Class 1.

Billy

Some suggestion.
Option 1:
As part of the negotiation to purchase, ask the company to commission the new equipment on site and provide you with a test certificate. Then put it on a service contract with the company.

Option 2:
Reprogramme your automatic tester with a class1 test that has the earth continuity test removed. If you have a tester that you cannot set up custom tests on, get our some resistors and capacitors, a DMM and try to remember how to do it the old way. That will tax quite a few people brought up on automatic testers.

Before people say it is not a full test if you do not check the earth; do you test every exposed metal part individually when doing an earth continuity test or just attach the probe to the earth stud and hope all the other parts are connected to it?

Robert

Just to add to the mix so to speak.

506N3 tech specs

Bottom of page.

Anybody out there familiar with the GE Dinamap PRo series vital signs monitor? Class 1 BF, non-accessible earth, non-earthed accessible parts.
I test Class 1, non-accessible earth, and test the accessible conductive comms connector for enclosure leakage and insulation resistance (which are included in Class 1 EST). There's no accessible conductive parts, that are earthed, to test - I test the mains IEC earth-bond seperately.

Under normal and SF condition, with no accessible earthed conductive parts on the enclosure, adequately isolated non-earthed accessible conductive parts on the case, and with adequate mains to earth seperation internally, electrically and mechanically sound enclosure, what's the most significant risks to the patient or operator on this Class 1 piece of equipment?

Is it if the earth becomes O/C internally or the earth in the mains lead fails between inspections or is it if a live part detaches and comes into contact and causes excessive leakage current or voltage on the non-earthed accessible connector, for example?

By internal inspection on evaluation it can be determined that neither of the internal failures is likely to occur in normal use and a life-threatening, high-risk, scenario under SFC is unlikely (although there were problems with securing the IEC sockets, on earlier versions, hence difficulty in keeping exposed mains inside the device!).

The failure of the detachable mains lead due to flexing and abuse is much more likely nowadays. EST is about looking as much as testing with an instrument. EST still requires those doing the testing to know what the test instrument is doing and why.

I open up equipment routinely on service to do repairs and routine servicing so looking for simple connection problems is not really too much trouble. We inspected on evaluation at the last place I worked - before we decided to puchase - this meant we knew what the build quality was like and how to test the device before we bought it. The PPQ, supporting documentation and equipment markings give us the information necessary to apply the essential tests.

If it's class 1-whatever but it doesn't have an accessible earth, don't you test it to class 1-whatever but note it as not having an accessible earth?

Cheers
Mark