How is "secundary circuits..mounted on material.." defined? (Cl 13.1.2)

[Loekje]

Hi forum,

Like probably everyone else we try to avoid reverting to a fire enclosure.
I have some trouble interpreting the first dot of second dash of 13.1.2:
- Secondary circuits meets all of the following conditions:
• mounted on material with a flammability classification of V-1 in accordance with IEC60695-11-10 or better. (and then another 3 easier dots..)
We have a connector flexPCB (0.1mmm polyimid) with only copper traces.
I found out that our flex manufacturer will not classify the flex with a V-1 classification with a rationale: "when you make materials this thin a lot non-flammable classified materials may become flammable". I'm not an expert in Polyimid or flammability so I cannot judge this statement. I should think that the amount of copper on the flex has it's influence on flammability as well.

Our flex only has copper traces, of course wide and thick enough to accommodate the maximum of 20mA currents at maximum 2V.
Is this considered as "circuits mounted on a material?", and if so: is there any way to dodge the requirement?
I have heard from the VTM classification, but that is not mentioned in 60601-1.

And when a circuit is clearly mounted on a UL V-1 FR4 PCB, when is "touching" considered "mounting", like with connectors in a housing?

Thanks for reading this.

Loek

 

[Peter Selvey]

There is an option to limit the power to the circuit to 15VA, and then you don't have to worry about anything. Generally if you are talking about traces that are only rated for 20mA/2V that would be the easiest option. Most circuits of this kind would be limited to <15VA at the dc/dc converter, if not, it's pretty easy to add a device like a PTC in the circuit to make sure it is <15VA.

The 4 dots referred to (e.g. V-1 flammability) are for secondary circuits with up to 100VA available power, so they are kind of mid range requirements for mid range power (15-100VA), and then >100VA is the high level requirements.

 

[Loekje]

Hi Peter,

My (EVS-EN 60601-1 AMD2) lacks an "or" between the dash " The construction of the supply circuit etc." and the dash "Secondary circuits meet all etc..". So I understood it to be <15W "and" the secondary circuits requirements.
When I took an old paper version of ANSI/AAMI ES60601-1:2005/(R)2012 out of the closet there clearly is an "or".

Can you verify that the "or" should still be in the latest amendment?
If so, this is *very* annoying....

Thanks,
Loek

 

[Peter Selvey]

Interesting.

I previously bought the same version since it was cheap but it's a pain to use especially when you transfer to a new PC. Good to know it has other issues so worth to avoid.

Now have the ANSI/AAMI version (very expensive!!!) but at least it clearly shows the "or" in between the options. Also note there are 4 different options in that section: 15W (in general); 100VA for secondary circuits; high integrity components and finally the fire enclosure. Each of these four options is separated with an "or" and it wouldn't make sense otherwise.

 

[Al_Z1]

Hi, i have the same EVS EN, and it looks exactly, like Loekje decribed.
But ANSI/AAMI version is modified from the base IEC 60601-1 (at least it is written on the free 1st page from ANSI store of this standard). So now I am curious, could it be, that this difference is intended? As these lines with additional options etc are from ammendment to IEC?

 

[Peter Selvey]

The original version (3.0) only has two options for avoiding fault testing, and is phrased:

- Option L (≤15W) [this is the sixth dash in the original clause]
or
- Option F (Fire enclosure)

The amendment says, after the existing sixth dash, insert the following:

- Option S (Secondary, ≤100VA, etc.)
or
- Option H (high int. char.)
or

So there is a valid question: does the "sixth dash" include the "or" or not. This is not defined, but it makes sense to consider it part of the dash, which results in:

- Option L (≤15W)
or
- Option S (Secondary, ≤100VA, etc.)
or
- Option H (high int. char.)
or
- Option FE (Fire enclosure)

Otherwise, you end up with:

- Option L (≤15W)
- Option S (Secondary, ≤100VA, etc.)
or
- Option H (high int. char.)
or
or
- Option F (Fire enclosure)

This clearly does not make sense. But it seems that EVS EN seems to have done is exactly this. I wonder if the two "or" appear consecutively in the standard? My EVS EN copy won't open anymore on a new PC.

 

[Loekje]

Like myself everyone makes mistakes.
So I'm not even angry nor disappointed that these type of misprints or typo's can occur (Although it did cost me some days trying to circumvent what seems to be a non-existing problem).

What does irritate me is that these standards are so costly that there is no easy way to check up whether things are applicable or not. If we were able to lay a few versions side-by-side it would be easy to figure out misprints.
Also having to buy the 64 (!) normative references to other standards is crazy (which have references to other standards as well, ad infinitum) of which you cannot tell on forehand whether they are applicable to your product or not, let alone all the collateral and particular ones with their subsequent references... sigh.
De facto they are "the law", I do not know a single product that shows regulatory compliance without using standards.
Standards should be freely accessible.

 

[Al_Z1]

My EVS EN copy won't open anymore on a new PC.

Well, I buy these EVSes with 1-time print option, than print them, scan, OCR and use, to be not dependent of PC.

 

[Loekje]

I brought this under the attention of the Estonian Standards Organization.
This was their reaction:
"Thank you for your feedback. We would like to express our sincere gratitude for bringing to our attention an error that occurred during the consolidation of amendments into the standard main text. We assure you that the necessary correction will be made as soon as possible. Once the corrected version is available, you and other customers will be notified, and you will be able to download the corrected version from your account. The estimated release date for the corrected standard is December 5th."|

So kudo's to EVS for quickly picking this up.

I have only one question left to this forum: this may be interesting to more people than that are attracted to the title of this thread.
Can anyone edit this title, or should I start a new thread, or anything?

 

[Al_Z1]

ESO sent corrigendum:

Spoiler