See 7.2.4.1 of the standard ( my bold text):
Rationale: Ungrounded equipment, or*ungrounded part(s) of equipment,*
cannot discharge
itself similarly to class I mains-supplied equipment. If the charge is
not removed before the
next ESD pulse is applied, it is possible that the EUT or part(s) of the
EUT be stressed up to
twice the intended test voltage. Therefore, this type of equipment or
equipment parts could be
charged at an unrealistically high charge, by accumulating several ESD
discharges on the
capacitance of the class II insulation, and then discharge at the
breakdown voltage of the
insulation with a much higher energy.
Best wishes
John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK
On 2020-03-12 15:53, Elliott Martinson wrote:
Hi Everybody,
We’re having some disagreements regarding the 61000-4-2 standard. In
the section “ungrounded equipment”, it states that ungrounded
equipment or part(s) of equipment shall have the charge removed in
between ESD pulses in order to not over-test.
We have a product that only fails pre-compliance when repeated ESD
pulses are applied to a floating metal knob without removing the
charge in between (eventually there is a second discharge between the
knob and the enclosure). The product as a whole is “grounded equipment”.
Since the issue only happens when the charge isn’t removed in between
pulses, is this a pass or a fail?
Thanks,
Elliott Martinson
Controls Engineer
Sub-Zero/Wolf
elliott.martin...@subzero.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 <mailto: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 <mailto:sdoug...@ieee.org>>
Mike Cantwell <mcantw...@ieee.org <mailto:mcantw...@ieee.org>>
For policy questions, send mail to:
Jim Bacher <j.bac...@ieee.org <mailto:j.bac...@ieee.org>>
David Heald <dhe...@gmail.com <mailto: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>