Hi Rich. Thanks for your feedback.
Correction/clarification. I was not trying to ‘convert’ to DC using 1.414 (root 2). I merely used that ‘multiplication factor’ (1.414 & sometimes just 1.4) based on the widely used/misused?/abused? that is used in the industry when determining ‘equivalent’ DC values, just like one commonly does when calculating the hipot test values. See: https://electrical-engineering-portal.com/what-is-hipot-testing-dielectric-strength-test <https://urldefense.proofpoint.com/v2/url?u=https-3A__electrical-2Dengineering-2Dportal.com_what-2Dis-2Dhipot-2Dtesting-2Ddielectric-2Dstrength-2Dtest&d=DwMFaQ&c=q6k2DsTcEGCcCb_WtVSz6hhIl8hvYssy7sH8ZwfbbKU&r=9-kTQUJB47k5_bHz_YekCwOWfoQDGgqgofVdnvpCXhM&m=X4OfXcJKn2LCMhQAhagkIEb6yDHp7Th9Mn0aSM9F6M4&s=57RvY_cM21TMTgAGuiIGMnZD0a7EcjWCvdfn0geu-kw&e=>, where Jignesh Parmar quotes in his article: “Therefore, if we use dc test voltage, we ensure that the dc *test voltage is under root 2 (or 1.414) times the ac test voltage, so the value of the dc voltage is equal to the ac voltage peaks.”* Another classic example comes from the 60950 standard for hipot values. 1500 VAC/2121 DC (calculation factor = 1.414) That being said, I look forward to hear a response from someone on TC66 on why they chose 70V. It would also be great if you could do a whitepaper (& speak) on the understanding of how the body reacts to AC & DC for this year’s PSES symposium in Chicago? 😉 Regan On Tue, Feb 25, 2020 at 4:07 PM Richard Nute <[email protected]> wrote: > > > > > Hi Regan: > > > > The “bump” occurred from 1st edition, 1990, to 2nd edition, 2001. The 2nd, > 2001, and 3rd, 2010, are the same. > > > > Be careful with your math and DC interpretation. The rms voltage limit is > 33. The ac peak is 1.414 x 33 = 46.7. The DC is 70, which is unrelated to > the AC voltages (which is because of how the body reacts to AC and DC). > > > > As to the rationale for the change from 1st to 2nd, I suggest you find a > member of TC66 and ask for the documents preceding the 2nd. > > > > Touch voltages are specified in IEC TS 61201. In this standard both 30 > and 33 volts rms are listed, with very little difference in body reaction. > Same for 60 versus 70 volts DC. > > > > Best regards, > > Rich > > > > > > > > *From:* Regan Arndt <[email protected]> > *Sent:* Tuesday, February 25, 2020 2:38 PM > *To:* [email protected] > *Subject:* [PSES] IEC 61010-1:2010 hazardous DC voltage > > > > Dear fellow members, > > > > I am trying to understand the 'rationale/history' of why TC66 bumped up > the DC voltage by a mere 4 volts for hazardous voltages. > > As we know by simple math, 46.7 Vp x 1.414 = 66 VDC.............where, why > and how did the extra 4 volts come about? > > I need a history lesson here.... ;) > > > > Also, will these voltages also come back to normal in Ed 4? (i.e. 42.4 Vp, > 60 VDC) > > > > Thanks for shedding any light on this? > > > > Regan Arndt > > > > > > - > ---------------------------------------------------------------- > > 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) <http://www.ieee-pses.org/list.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]> > - ---------------------------------------------------------------- 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]>
