I have a Dielectric Voltage-Withstand Test question. Paragraph 49.1.1(b) of UL 508 says a product will withstand a potential between terminals of opposite polarity with the contacts closed. By contacts I assume they are referring to On-Off switch contact and relay contacts so the potential will be presented throughout the circuit. Given that this is the intent of the paragraph, the circuit is on and will pass current as intended in normal operation.
Paragraph 49.1.3 says "A transformer, a coil, an electronic part, or a similar device normally connected between lines of opposite polarity is t be disconnected from on side of the line during the test described in 49.1.1(b)." This makes sense and is easy to do if you have a very simple circuit - simply open the load and conduct your dielectric test. But if you have a more complex circuit things are more difficult to figure out. Our immediate situation is one in which a 24VDC source is fed to a voltage regulator. We can remove this component, but by doing so, we open the circuit and test only the trace between the DC input and the regulator; the remainder of the circuitry is unaffected by the potential and thus is untested. Is the proper method then to lift the ground leg of the regulator and then work on down the line lifting each current conducting component to ground? Dan Kinney Horner APG ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
