>From Table 3 we get the following Remark, under both rows 3.2 and 3.3:
"For application to input ports see note 4".
If I read that the way it is written, with no punctuation, then the
meaning that I get from it is that the tests are required on both DC
input and DC output ports, but if you are testing an input port, you
should read note 4. I admit that the logical expectation is that they
meant it the way they wrote it.
If, however, we add a semi-colon, the meaning changes considerably:
"For application to input ports; see note 4". In that case, the meaning
I get from it would be that the test is only required on DC input ports.
Of course I have no reason to believe that they forgot this colon,
except that perhaps it makes more sense that way.
What got me thinking about this is partly the contents of note 4, which
gives a 10m criteria for input cables and says nothing about output
cables. Surely in the real world the likelihood of having real surges
and EFT events on DC output ports, by way of conduction from the mains
through the product, is fairly low, given that the product's impedances,
isolation barriers, etc, lie between the mains and the DC output.
Besides, if the damage from that sort of event is what they are worried
about the tests on the input port(s) would suffice. So I concluded that
they must be concerned about surges or EFT's that result from coupling
onto the output leads from external sources, in which case I would
expect a length criteria.
Does anyone know the intent? What are test houses actually doing -
testing both or just DC inputs? If they are testing DC output ports, is
there a 10m criteria? Can anybody explain or speculate why a 10m
criteria for DC output cables would not be appropriate?
Thanks for your help,
Jim Eichner, P.Eng.
Compliance Engineering Manager
Xantrex Technology Inc.
e-mail: [email protected]
web: www.xantrex.com
Any opinions expressed are those of my invisible friend.
Confidentiality Notice: This email message, including any attachments,
is for the sole use of the intended recipient(s) and may contain
confidential and privileged information. Any unauthorized review, use,
disclosure or distribution is prohibited. If you are not the intended
recipient, please contact the sender by reply e-mail and destroy all
copies of the original message.
This message is from the IEEE Product Safety Engineering Society
emc-pstc discussion list. Website: http://www.ieee-pses.org/
To post a message to the list, send your e-mail to [email protected]
Instructions: http://listserv.ieee.org/listserv/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas [email protected]
For policy questions, send mail to:
Richard Nute: [email protected]
Jim Bacher: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
