Scott, I very much prefer the two-channel o'scope dual-probe method using the A-B function. Alternatively a differential o'scope probe is an option, although they tend to be rather pricey. It is usually not necessary to get high speed probes as this is only line frequency.
It is inadvisable to isolate the o'scope and use the grounding pin on Neutral as any errors can cause the o'scope chassis to go live. In that case, even the set screws holding knobs on the controls would be a potential shock hazard. -Doug Douglas E Powell Laporte, Colorado USA [email protected] LinkedIn <https://www.linkedin.com/in/coloradocomplianceguy/> (UTC -06:00) Mountain Time (US-MDT) On Mon, Oct 17, 2022 at 9:17 AM Scott Xe <[email protected]> wrote: > In order to judge if there is no risk of electric shock from charged > capacitors, it is required to measure the voltage across L and N of mains > plug after the removal of power input. To avoid grounding loop between > test equipment and the unit under test, an isolating transformer is > strongly recommended. I have learnt another way by using Add Function and > two hot probes of a dual channel DSO. Can someone advise which way is more > common in safety conformity test. Especially the latter one, I have not > tried it yet before and appreciate any notes I must take in the measurement. > > Thanks and regards, > > Scott > >> - > ---------------------------------------------------------------- > > 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 > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > - ---------------------------------------------------------------- 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 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: Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
