EBME Forums Forums Free discussion Free discussion IEC 62353 - MISSED OPPORTUNITY?

Hi Geoff,

Being part of the EU does not mean that each member country has identical laws. This would be nice, lets all adopt the German laws. Mandatory PAT testing on non medical equipment (VDE0701/0702), medical equipment (VDE0750/0751), laws on fixed installations (VDE0100) and perhaps, remove the speed limit on our motorways and whilst we're at it, lets adopt the Euro before the Torries come back in power. I'm up for it.

The IEC62353 is aimed to deal with all different IEC's / VDE's EN's MDA's, AS/NZ's, AAMI's, NFPA's, CSA's and so forth. Looking at the UK, there is no single approach to routine maintenance, yet as you correctly state, Medical Equipment has not changed much over years let alone by geographical area.

So I concluded in the seminar that the IEC 62353 is a welcome standard for all involved in the medical sector, not just the professionals working in the UK but far beyond.

Anyway Geoff, you wouldn't know the nearest airport to Cloud Cuckoo Land so I can check the venue?

This argument should focus on the effectiveness MHRA who seem to be a toothless organisation. Barney mentioned how standards are enforced more riourously in Germany and Australia, but the FDA in America are the "daddies" of regulatory bodies. All American equipment manufacturers live in fear of the FDA. Perhaps our MHRA should take a leaf out of their book. I can imagine a squad of black jacketed troopers with MHRA logo on their backs decending on an unsuspecting Biomed department for using the wrong safety test standards. But seriously, why go to all the trouble to write the standards if they are not mandatory or enforceable?

I think I can answer that one, Bill. This is Britain, Mate. The land of muddling through, making do, and doing it on the cheap!

There's your answer, John, you're already in it!

No - not a missed opportunity but possibly mis-directed and possibly being used as a springboard to develop and sell a product which I totally disagree with if it is the case.

This aside it's a more prescriptive approach to testing and could be used to make the applicability of tests, for those technically less competent or less knowledgeable, less ambiguous than the current standards for routine purposes.


I'm left wondering why the UK experts voted against 62353 if, as a standard for routine safety testing, it has significant benefits over and above the tests that are specified for 60601-1?

More guidance, i.e. a standard that's not mandatory, is not what's needed, it's more prescriptive routine testing legislation that is needed from the HSE, MHRA and DoH based on evidence plus a standard for routine testing that's acceptable to UK experts.

IEC 62353 appears to follow identical tests to 60601-1 except that it specifies IR testing (which, as it happens, is performed on most if not all of the automated/semi-automated "pick and mix" "60601-1 compliant" electrical safety testers that I've ever used).

IEC 62353 specifies the MINIMUM earth bond test current of 200mA - higher test currents can be used.

An important factor is that IEC 62353 does not include the single-fault tests that ensure medical devices are capable of remaining electrically safe under SFC.

IEC62353 also applies limits from earlier revisions of 60601-1 that may no longer be consistent with the 3rd edition 60601-1 standard.

On balance IEC62353, as it stands, may potentially add to confusion and does not necessarily make safety tests (that are generally perfomed using automated/semi-automated safety testers) easier, safer or significantly faster. Not for Engineers that apply the tests after re-manufacture of systems, during evaluation or acceptance checks, anyhow.

My view is that IEC62353 may not be suitable for anything but routine test purposes hence I'd be inclined to continue testing using a "60601-1 compliant" with IR tests and earth-bond test current that is capable of overcoming poor contact resistance and surface contamination, for accetance, evaluation, re-manufacture and after repairs.

Accepting the fact that we cannot possibly perform testing to all of the requirements in the 60601-1 standard, since some are destructive - that's not what we try to achieve with safety testing in the field and this has been the case for years since BS5724 was published in the 70s.


As well as the Rigel 288 if you want a safety tester that can be used as a versatile bench instrument for Engineers used in evaluation, acceptance-checks and tests after re-manufacture of stuff like video endoscopy stacks, etc, then I'd suggest the highly portable (mains operated) Gossen Metrawatt Secutest SIII .

This includes IEC62353 (VDE0751) and a host of other standards/limits for British/European Standards IT/ Telecoms, Laboratory, PAT, Household, etc. Internal printer, 4-wire kelvin Ohms measurement, in fact some nice "instrumentation" features with some useful accessories.

It doesn't include any "gimmicks" plus, to be fair and balanced, I'd say that its database connectivity/data storage and retrieval is not really setup for high volume tests, like the QA90 or Rigel 288, for throughput, and it's not quite as configurable when it comes down to mixing applied parts (unless this has now been addressed in later software) but it is a decent bench instrument for engineers (Voltmeter, Ohmmeter, Ammeter, Power-Factor, Functional tests, etc).

Very competitively priced with a 25A, 10A/200mA earth bond tests and, more importantly, specified tolerances and errors that are more meaningful than many of the technical specifications and performance metrics that're given by the competition. Perhaps this is because it's manufactured for the German market and has to comply with legislation.

Although the high current pulse followed by 200mA earth bond test of the Rigel 288 is novel it only has single wire, i.e. Ohms needs to be zeroed, earth bond resistance measurement, plus the accuracy of measurement appears to be outside those generally specified in IEC62353 due to a combination of display resolution and basic accuracy, for example.

I'm of the opinion that NO electrical saftey tester, including the Rigel 288, can avoid presenting potentially injurous voltages or currents to the operator or even the equipment under test. That's in the nature of electrical safety testing unfortunately.

I wouldn't be surprised if there are disclaimers and warnings about the potential for damaging or injurous voltages and currents during testing in the operator manual - just like all the other EST manuals.

Well, my two cents on the subject...

I think that the main problem with IEC 62353 is that, as it is related to the second edition of IEC 60601, it does not take into full consideration the aspect of risk management.

A lot of people tend to think that the tests and limits of IEC 60601 are "rigid", meaning that they can´t be changed, but the truth is that the standard always had a "safeguard" clause (it´s clause 3.6 in the second edition) which says that the construction of the equipment could be different from the standard if it was demonstrated that the risk level is the same as would be if the clause of the standard was met (nowadays it would say - if the residual risk is acceptable). This was not used much because there´s was some difficult in applying the concepts of risk management without a defined framework (and this was one the reasons of the development of ISO 14971 and it´s incorporation as a regulatory requirement in the new edition of IEC 60601).

What it means is that the equipment could be constructed in a way in which the tests of the standard would not be aplicabble, or would be, but in a diferent way - change in test method or limit values, or both or whatever. Or new tests would have to be developed to test the risk controls - and safety standards, in a risk management framework, are nothing more than a collection of agreeded risk controls and tests to verify that these risk controls, which are not always the best or cheapest ones, are effective.

This mindset could make the life of people testing equipment in a post-marketing environment really hard. But that´s the way it is, as the regulatory requirements of manufacturers are risk management-based.

The truth is, there´s no way for this to function correctly if manufacturers do not declare the tests that need to be performed on their particular equipment to mantain them safe. That´s because the risk management information is not available to the end-user.

All in all, i think the standard is a great step in one direction, but i´m not sure that is the right one.

I'm not going to get into discussing standards and clauses in standards since nobody wants to wade through that but I think that problems are likely to be caused by the application of 62353 that may be inconsistent with current 60601-1.

Without thinking about it too deeply I think that it is possible to fail a device using the leakage limits in the 62353. For example when some of the current leakage limits are greater in 60601-1, e.g. current earth leakage requirements.

62353 tests may be performed that do not take into acccount the single fault failures that medical devices are intended to be tolerant of. Thus a 60601-1 compliant device under SFC may pass a 62353 EST. Is this a safe medical device?

For example I suppose it's possible for a SFC to be present under 62353 testing, e.g. enclosure leakage, earth O/C, and still pass leakage tests on a device designed to pass 60601-1 under SFC with accessible conductive parts. How would we detect this was the case?

This device could still have a fault on it and pass enclosure leakage tests and earth leakage tests, obviously, since earth is O/C, with enclosure leakage from accessible conductive parts limited by adequate construction to 60601-1. Could we tell the difference?

My personal view is that 60601-1, itself, should include its own requirements for routine testing or 62353 should be tied even more closely to it, to be amended concurrently with it, or even incorporated into 60601-1.

Whatever happens in the future people like us, in maintenance, are going to need to make references to 60601-1 when acceptance testing and evalutating medical devices. Even if we apply a routine medical electrical testing standard.

We need a clear and concise rationale, that is uncluttered by risk-assessment approaches, and one that outlines a suite of non-destructive tests that can be used to give pass/fail criteria when rotuinely safety testing medical electrical devices.

All we want to know, Richard, is:-

Does this mean we have to bin all our old (and existing) electrical safety testers?

I don't think so Geoff. The most significant difference I can see between the direct method of 62353 and 60601-1 is the explicit application of IR testing and there's not much in that to be honest since most 60601-1 compliant testers include 2 out of 3 of the IR tests described in 62353 I think. The problem is inconsistency between current 62353 limits and applicable 60601-1 limits, I think.

The 62353 standard introduces some concepts that, in my experience, have been used by skilled, experienced and appropriately trained technicians without having it written down in a standard. Saying this I think 62353 formalises some useful ideas relating to what should be inspected on a PM. Some are just plain common sense in my view.

I've never come across any "60601-1 compliant" commercial medical electrical testers, intended for maintenance rather than manufacturing, that have ever applied destructive or stress tests to devices so the argument about 60601-1 tests being destructive is one for test houses, tester manufacturers and sales-persons to worry about not us.

Ooops, correction (or should I say clarification?):


For example I suppose it's possible for a SFC to be present under 62353 testing, e.g. enclosure leakage, earth O/C, and still pass leakage tests on a device designed to pass 60601-1 under SFC with non-accessible earthed and accessible non-earthed conductive parts. How would we detect this was the case?

Hello all

It could be a surprise, but 99 of 100 manufacturers and hospitals in Brazil seem to apply the 4KV dielectric strenght tests, which are destructive, on post-marketed equipment. This is the kind of untrained people i think would benefit more from the standard.

Anyway, i don´t think there´s need to scrap any safety tester. In fact, someone who knows what he´s doing can always make the tests with simpler equipment (a True RMS Multimeter and some resistors for the leakage tests? It surely work - i remember one colum from Rich Nute in the IEEE PSTC Newsletter in which he advised the use of a normal multimeter to make the tests, because the results would be acceptable anyway - just remembering that the objective of the post-market tests is not the same of the pre-marketing one).