----- Original Message ----- From: Luiz Claudio <[email protected]> To: Rick Linford <[email protected]> Sent: Sunday, April 29, 2001 9:01 AM Subject: Re: EN60950 (UL1950, IEC 60950) On off switch marking.
> Rick, > > I will give my oppinion, based on the experience that I have dealing with > IEC60335-1. I assume this requirement is basically the same as the one > stated at IEC60950 (I'm not experienced with this standard). > > Our product also has a control that opens only the "hot" side of the supply. > My interpretation is that the "0" marking is required. Actually, all > European/South American agencies that I've been working with require such > marking. > > As far as NTRL's are concerned, I would like to mention that UL has > published the second edition of UL 60335-1, Standard for Safety of Household > and Similar Electrical Appliances, Part 1: General Requirements. Since they > also have UL 1950 (which I believe has the same requirements of IEC 60950), > I'll use them as an example. > > Item 2.9.2 of UL 60335-1 standard says: > > "2.9.2 OFF POSITION: Stable position of a switching device in which the > circuit controlled by the switch is > disconnected from its supply. > NOTE - The OFF POSITION does not imply an ALL-POLE DISCONNECTION." > > Item 7.10 says: > > "7.10 The different positions of switches on STATIONARY APPLIANCES and the > different positions of controls on all > appliances shall be indicated by figures, letters or other visual means. > NOTE 1 - This requirement also applies to switches which are part of a > control. > If figures are used for indicating the different positions, the OFF POSITION > shall be indicated by the figure 0 and > the position for a greater output, input, speed, cooling effect, etc., shall > be indicated by a higher figure. > The figure 0 shall not be used for any other indication, unless it is > positioned and associated with other numbers > so that it does not give rise to confusion with the indication of the OFF > POSITION. > Compliance is checked by inspection. > NOTE 2 - The figure 0 may, for example, also be used on a digital > programming keyboard." > > Therefore, as I said before, at least for household appliances this > requirement is applicable and we use "0" to indicate the OFF position, > regardless of the fact that the switch opens only one leg of the supply. I > believe the same applies to IT equipment. > > However, you should search the standard to see if your equipment (in > particular) would require a two-pole switch. For example, if you have > capacitors permanently subjected to the supply mains voltage (eg used for > radio interference suppression) and this capacitor is disconnected from the > supply by an on-off switch, this switch has to be double-pole if the > capacitor is connected to earth. > > Regards, > > Luiz > ----- Original Message ----- > From: Rick Linford <[email protected]> > To: <[email protected]> > Sent: Friday, April 27, 2001 1:25 PM > Subject: EN60950 (UL1950, IEC 60950) On off switch marking. > > > > > > Hi All, > > > > When a switch opens only one leg of the mains to control power to > > equipment should it be marked with the "l" and "O"? > > > > Background: > > > > Three different engineers from three different NRTLs indicated it is > > permitted, two even required it. A different engineer for one of the > > NRTLs and two other respected individuals indicate it is prohibited. It > > will be interesting if members of this list will have the same 50/50 > > split or if there is a correct answer. > > > > (single phase 100 to 240 VAC, 2A, 50-60 Hz, intended to be shipped US, > > Canada, EU and generally internationally) > > > > To help, IEC 60950 (1999), section 1.7.8.3 Symbols, is shown below. > > > > Where symbols are used on or near controls, for example switches, push > > button, etc., to indicate "ON" "OFF" conditions, they shall be the line > > l for "ON" and the circle O for "OFF" (60417-1-IEC-5007 and > > 60417-1-IEC-5008). For push-push type switches the symbol {line in side > > the circle} shall be used (60417-1-IEC-5010). > > > > It is permitted to use the symbols O and l to indicate the "OFF" and > > "ON" positions of any primary or secondary power switches, including > > isolating switches. > > > > A "STAND-BY" condition shall be indicated by the symbol {line breaking > > the circle at the top} (60417-1-IEC-5009). > > > > My bias was not included in the 50/50 statistics noted above but I > > believe it is required. > > > > Rick Linford > > Regulatory Engineer > > SonicWALL > > > > > > ------------------------------------------- > > 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: > > [email protected] > > with the single line: > > unsubscribe emc-pstc > > > > For help, send mail to the list administrators: > > Michael Garretson: [email protected] > > Dave Heald [email protected] > > > > For policy questions, send mail to: > > Richard Nute: [email protected] > > Jim Bacher: [email protected] > > > > All emc-pstc postings are archived and searchable on the web at: > > http://www.rcic.com/ click on "Virtual Conference Hall," > > > ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
