Dave,

I was thinking if first ask Meanwell or here, and decided to ask here believing I will learn more. Till now from Meanwell reseller in Poland I know that for some supplies they specify that output is SELV, but for this one there is no such information.

I plan to ask them following discussion here.

Regards
Piotr


W dniu 2017-11-22 o 19:09, Nyffenegger, Dave pisze:
In order for a power supply to meet SELV requirements it must pass all of the 
tests in the EN60950-1 standard for SELV which means component failure testing 
among other things, not simply isolation testing.  Meanwell power supplies that 
I have researched have been SELV.  Meanwell  has been very responsive if you 
contact technical support and will provide the lab reports showing the power 
supply passed the relevant SELV clauses in the standard.

If the power supply is UL approved the UL certificate available on the UL web 
site may indicate whether or not it's SELV as well as power supply class and 
other basic ratings.

-Dave

-----Original Message-----
From: Piotr Galka [mailto:piotr.ga...@micromade.pl]
Sent: Wednesday, November 22, 2017 12:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Safe powering 12V doorlock

Dear safety experts,

Help me to make me sure that it is save to use the following power supply:
http://www.meanwell.com/webapp/product/search.aspx?prod=DRC-40
to power 12V doorlock with not earthed 12V supply.

I think that from practical point of view it is save but how it looks formally.

This supply is TUV EN60950-1 approved, and input to output is tested with 
3kVAC. There is no info if output is SELV or ELV.
Before asking them if their output is SELV I'd like to know if it has to be 
SELV, or if from info I have I can find it is SELV. I wont to use this case to 
learn myself more about safety.

Why I'm not sure.
1. I suppose that 12 doorlock manufacturer can use only functional isolation 
betwean 12V and its metal casing as he can assume (I think) that he gets safe 
voltage.
If I'm wrong with it let me know.
2. Then as doorlock metal casing can be touched by user than 12V have to be 
SELV circuit I think.
3. I'm not sure if the 12V output from this supply is SELV - is it enough to 
test the isolation with 3kV.

In EN 60950-1:2006 5.2.2 I understand that if output is not grounded or there 
is no protective screen than table 5C should be used.
I assume not earthing 12V.
I don't know if there is protective screen inside but as I can imagine such 
supply there have to be feedback and it is probably opto feedback - so can 
there be metal screen betwean LED and opto element and opto will work? I'm not 
sure if I understand well what is screen in accordance with 2.6.1 e).
  From Annex G I understand that for Overvoltage Category II transient voltage 
(Europe) will be 2k5V and from table 5C I have 5kV test needed.
So 3kV written in datasheet looks being not enough.

All till now I have written assuming the Overvoltage Category II. But reading 
Annex Z I'm not sure if access control system, as permanently installed, is 
integral building wiring or not. It seems me more like a fuse panel then 
permanently connected electric cooker. If category III then I end with 8kV 
testing - much more than 3kV.

It is TUV approved and under Applications the producer lists Access Systems so 
powering doorlock should be save. If it is true - where is my mistake.

Best Regards
Piotr Galka

-
----------------------------------------------------------------
This message is from the IEEE Product Safety Engineering Society emc-pstc discussion 
list. To post a message to the list, send your e-mail to <emc-p...@ieee.org>

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to 
unsubscribe) List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas <sdoug...@ieee.org>
Mike Cantwell <mcantw...@ieee.org>

For policy questions, send mail to:
Jim Bacher:  <j.bac...@ieee.org>
David Heald: <dhe...@gmail.com>


-
----------------------------------------------------------------
This message is from the IEEE Product Safety Engineering Society emc-pstc discussion 
list. To post a message to the list, send your e-mail to <emc-p...@ieee.org>

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas <sdoug...@ieee.org>
Mike Cantwell <mcantw...@ieee.org>

For policy questions, send mail to:
Jim Bacher:  <j.bac...@ieee.org>
David Heald: <dhe...@gmail.com>

Reply via email to