From: John Cochran Sent: Friday, September 05, 2014 3:47 PM To: '[email protected]' Subject: UL 60950-1 clause 2.2.3
I am doing compliance testing on an outdoor computer/display and am having problems with complying with clause 2.2.3 of UL 60950-1 and clause 6.2 of UL 60950-22. When the earth ground is disconnected, there is an AC potential on the chassis ground that is ½ of the line voltage. At 240VAC, there is 120VAC on the ground. Since everything is grounded in the system and it is in an aluminum enclosure, I have this potential everywhere. I cannot find an open frame AC power supply that does not do the same thing. What is it that I am doing wrong. The UL 60950-22 standard says the maximum AC voltage that is acceptable is 15VAC. John Cochran 425 Caredean Drive Horsham, PA 19044 PHONE: 215-443-3400 X219 FAX: 215-443-3002 - ---------------------------------------------------------------- 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
