Insulation Barrier Testing - According IEC 60601-1

[nikolaos]

Hello All,
According IEC 60601-1, testing an insulation barrier, both dielectric and spacing requirements are necessary or it is enough only the dielectric high voltage test? Is there any current limit during the dielectric high voltage test?
Thank you

[Jennifer Kirley]

Does anyone have advice for nikolaos?

[Marcelo Antunes]

Hi, just a quick answer cause i´m offline for some days: you need both spacing and dielectric strenght.

And there´s no current limit for the dielectric test in IEC 60601.

[Peter Selvey]

Dielectric strength and spacings are different requirements.

Dielectric strength is an ageing test for solid insulation, such as on wiring, in transformers and optocouplers.

Spacings are for two other reasons: one (clearance) for short term spikes in the order of 1000-3000V that occasionally appear on the mains, the other (creepage) is to have enough space to protect against long term dust/pollution accumulation.

So you really need to assess all three separately.

Current limit for dielectric strength: IEC 60601-1 does not specify a current limit for the HV tester, however other standards specify 100mA. This high current is theoretically important due to the effect of partial breakdown, but in practice modern insulating materials have dielectric strength well above the needs so it rarely has an impact.

Otherwise, because of EMC capacitors, you may need a HV current capacity of around 5mA.

The current pulled during a HV test is about 6 times the "neutral open" earth leakage current, e.g. if your equipment has 300uA @ 264V earth leakage in SFC (neutral open), you will see ~1.8mA leakage in the basic insulation test (@ 1,500V). It's a nice confirmation of your test set up to confirm this value. Double insulation test current is usually much lower (if not, something is wrong with your set up).

Yoroshiku,
(= regards in Japanese)
Peter

[nikolaos]

Thank you for all these information, indeed very clear and precise. Actually I have a discussion with an Italian Notify Body about Insulation Barrier Testing. I agree that both electrical (dielectric HV test) and mechanical (C&C) are both necessary to check the insulation, but the NB insist telling me that only dielectric test with 8mA of leakage current is enough. According them C&C check is not necessary. I work as a project engineer for a Medical manufacturing company and it is very useful for me to know what you think about this item, so any other opinions are very valuable.
Regards
Nikolaos

[Marcelo Antunes]

It´s weird that your NB aasks only for dielectric strenght, and weirder that they put a limit on the current for the dielectric strenght as the standards does not have that (it does not have a current limit but it defines how a test can fail by defining what is insulation breakdown).

Anyway, there´s a difference between what a standard requires and what a regulation requires. You are not required to comply with IEC 60601, although it´s desirable, and maybe that is the position of your NB. But keep in mind that, the way they´re are asking you, you are NOT in compliance with the standard, and may be at risk of having ptoblems in other places which have a more strict view on standards.

[nikolaos]

OK, but I asked to test according 60601-1. In the report is clearly written that they followed the testing procedure according 60601.1(1998). More, I found no isolation diagram in the report.

[Martin IT]

The compliance with the IEC 60601-1 is not mandatory but highly recommended. In my opinion the suggestion of the NB should be taken into serious consideration.

I've got the same problem ( I'ma a project engineer and I work with an Italian Notify Body ), and at the moment we perform only dielectric test with 8mA of leakage current.

Let me know the way you will forward!