Jim
I can think of a couple possible reasons.
Personnaly I am usually concerned with power line cross on shielded
communications cable.
Whereby 250Vac may be accidentally applied to the shield of the communication
cable. Also I am
not sure how well your typical configuration would handle a 2KV CM surge pulse
on a shielded
ethernet cable typical of a Industrial environment.
John Merrill
Schneider Electric
"Jim Eichner"
<Jim.eichner@Xant To: <[email protected]>
rex.com> cc:
Sent by: Subject: Ethernet connector
shield decoupling capacitor
[email protected]
03/07/2007 03:05
PM
We're being hit with a requirement that I don't understand.
We are using a shielded Ethernet connector that contains the typical 2kV
cap from the common point of the 75 ohm resistors to the shield. This
is used on the output of an off-the-shelf Ethernet transceiver module,
and the mfr of that module is telling us we need to connect the
connector shield to their digital ground through a 1nF 250V Y-cap, not
directly.
1. Why not directly connect the shield to digital ground?
2. Why would a Y-cap be required? The cap would be joining two parts of
the same circuit, so it would not be across an isolation boundary. I
can't think of a reason to require either the 250V rating or the Y
rating.
Any thoughts anyone?
Thanks,
Jim Eichner, P.Eng.
Manager - Compliance Engineering
Xantrex Technology Inc.
e-mail: [email protected]
web: www.xantrex.com
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/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]
Mike Cantwell [email protected]
For policy questions, send mail to:
Jim Bacher: [email protected]
David Heald: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
________________________________________________________________________
This email has been scanned for SPAM content and Viruses by the MessageL
abs Email Security System.
________________________________________________________________________
-
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/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]
Mike Cantwell [email protected]
For policy questions, send mail to:
Jim Bacher: [email protected]
David Heald: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email
______________________________________________________________________
