Re: EN60950 (UL1950, IEC 60950) On off switch marking.
Rick,
If you are using IEC950 you can mark the switch I/O, if you are using IEC60065 you are only allowed to mark a single pole switch with the "I" (on) symbol.
Ed
>From: "Rick Linford"
>Reply-To: "Rick Linford"
>To:
>Subject: EN60950 (UL1950, IEC 60950) On off switch marking.
>Date: Fri, 27 Apr 2001 10:25:19 -0600
>
>
>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
>
>
>---
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RE: EN60950 (UL1950, IEC 60950) On off switch marking.
I've worked on products which used triple phase inputs for different sections of the product and the main power ON/OFF breakers were usually barred together as one gang switch. I also had off from one of those phases a motor which had it's own ON/OFF switch. And all the switches were marked as "I/O". And that product passed testing for UL-1950 and EN60950. Not sure if that answers your question. Regards, Doug --- 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 Healddavehe...@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,"
En: EN60950 (UL1950, IEC 60950) On off switch marking.
- Original Message -
From: Luiz Claudio
To: Rick Linford
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
> To:
> 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.
> >
RE: EN60950 (UL1950, IEC 60950) On off switch marking.
Hi Scott,
The power cord acts as the disconnect.
Rick Linford
SonicWALL
-Original Message-
From: Scott Barrows [mailto:sbarr...@curtis-straus.com]
Sent: Friday, April 27, 2001 12:41 PM
To: Rick Linford
Cc: emc-p...@majordomo.ieee.org
Subject:Re: EN60950 (UL1950, IEC 60950) On off switch marking.
Hi,
If the switch is being used as the disconnect device it needs to
disconnect
both poles simultaneously (2.6.6). 1.7.8.3 only refers to on and off
indications of the equipment.
So I guess I need to know if the switch is being used as a disconnect or
just to turn the machine on and off.
Scott Barrows
Curtis Straus LLC
Rick Linford wrote:
> 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.
>
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Re: EN60950 (UL1950, IEC 60950) On off switch marking.
Hi,
If the switch is being used as the disconnect device it needs to disconnect
both poles simultaneously (2.6.6). 1.7.8.3 only refers to on and off
indications of the equipment.
So I guess I need to know if the switch is being used as a disconnect or
just to turn the machine on and off.
Scott Barrows
Curtis Straus LLC
Rick Linford wrote:
> 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:
> majord...@ieee.org
> with the single line:
> unsubscribe emc-pstc
>
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> Michael Garretson:pstc_ad...@garretson.org
> Dave Healddavehe...@mediaone.net
>
> For policy questions, send mail to:
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> 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,"
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Re: EN60950 (UL1950, IEC 60950) On off switch marking.
Hi Rick: There are three issues which we must address: 1. The safety function of the switch. 2. The safety function of all-pole disconnect versus one-pole disconnect. 3. The marking of the function of the switch. * The safety function of a disconnect device (for which a switch is acceptable) is: * to disconnect power in the event of some sort of safety incident within the equipment; * to disconnect power for the situation of servicing the equipment. For cord-connected equipment, I alway designate the plug or appliance coupler as the disconnect device. This means that the power switch is not an isolating switch. This solves the problem of one-pole versus all-pole switch requirements, and contact separation requirements. For the first function, a one-pole switch will satisfy all safety incident situations except (50-50 chance) phase-to-ground fault (in which case the building overcurrent devices provides the protection). For the second function, a one-pole switch satisfies the servicing situation for a polarized supply system with a polarized plug and socket. A one-pole switch does not satisfy the servicing situation for a non-polarized supply system. (However, the plug does satisfy the servicing situation.) In the situation you describe, you can designate the plug (or appliance coupler) as the disconnect device, and the on-off switch as a functional (i.e. not a safety) switch. According to the requirements you quoted, the "0" and "1" symbols may be used on *any* primary power switch. So, the symbols may be used on either a functional switch or an isolating switch. For marking, there is no requirement that the "0" and "1" symbols are restricted to isolating switches. However, isolating switches must be marked with the "0" and "1" symbols. Most of our products do not have a primary power switch. We use a secondary circuit functional on-off switch. Since we do not switch primary power, we do not use the "0" symbol, but the "stand-by" symbol. Best regards, Rich --- 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 Healddavehe...@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,"
RE: EN60950 (UL1950, IEC 60950) On off switch marking.
I hit the send button too soon. I forgot to mention the standby symbol. I
added that below.
Rick, let's start with the general requirement per clause 1.7.8.1.
The requirement is "Unless it is obviously unnecessary, indicators, switches
and other controls affecting safety shall be identified or placed so as to
indicate clearly which function they control. Indications used for this
purpose shall, wherever practicable, be comprehensible without a knowledge
of languages, national standards, etc."
Does the switch in question affect safety? Since the switch performs
a power on/off function, I would say yes. Are the "on" and "off" positions
of the switch understandable without markings? Probably not, so some kind of
marking is required and the type is specified by clause 1.7.8. as the famous
"I" and "O" (or the push button symbol or standby symbol).
Is it allowed to mark a power switch that only switches one side of
the mains? Yes, the marking is permitted by clause 1.7.8.3 to be applied to
"any primary power switches."
Putting all of this together, the answer is yes, marking is both
permitted and required on your power switch.
But, do you use the "OFF" or the "standby" marking symbol? A main
disconnect device (breaks all poles and has 3 mm spacings) may use the "O".
All other types of on/off switches may use the "standby" marking since the
use of the "O" marking would be misleading to the service person and create
a potential hazard during servicing. This is your case since you cannot
guarantee that the unswitched pole will be an earthed neutral.
So, the short answer is that the "I" and "Standby" markings are
required for your product.
Richard Woods
--
From: Rick Linford [SMTP:rlinf...@sonicwall.com]
Sent: Friday, April 27, 2001 12:25 PM
To: emc-p...@majordomo.ieee.org
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
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RE: EN60950 (UL1950, IEC 60950) On off switch marking.
Rick, let's start with the general requirement per clause 1.7.8.1. The
requirement is "Unless it is obviously unnecessary, indicators, switches and
other controls affecting safety shall be identified or placed so as to
indicate clearly which function they control. Indications used for this
purpose shall, wherever practicable, be comprehensible without a knowledge
of languages, national standards, etc."
Does the switch in question affect safety? Since the switch performs a power
on/off function, I would say yes. Are the "on" and "off" positions of the
switch understandable without markings? Probably not, so some kind of
marking is required and the type is specified by clause 1.7.8. as the famous
"I" and "O" (or the push button symbol or standby symbol).
Is it allowed to mark a power switch that only switches one side of the
mains? Yes, the marking is permitted by clause 1.7.8.3 to be applied to "any
primary power switches."
Putting all of this together, the answer is yes, the marking is both
permitted and required on your power switch.
Richard Woods
--
From: Rick Linford [SMTP:rlinf...@sonicwall.com]
Sent: Friday, April 27, 2001 12:25 PM
To: emc-p...@majordomo.ieee.org
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
---
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All emc-pstc postings are archived and searchable on the web at:
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RE: EN60950 (UL1950, IEC 60950) On off switch marking.
Hi,
Well here is the other side to keep it 50-50.
I have understood the requirement to be that the "O" symbol can only be used
when all power has been disconnected from the unit. I believe that if you
used a single pole switch on a grounded neutral system, it would be OK. Of
course, this is only OK if you can be sure that you know which will be the
neutral.
Ned
Ned Devine
Program Manager III
Entela, Inc.
3033 Madison Ave. SE
Grand Rapids, MI 49548
616 248 9671 Phone
616 574 9752 Fax
ndev...@entela.com e-mail
-Original Message-
From: geor...@lexmark.com [mailto:geor...@lexmark.com]
Sent: Friday, April 27, 2001 12:47 PM
To: Rick Linford
Cc: emc-p...@majordomo.ieee.org
Subject: Re: EN60950 (UL1950, IEC 60950) On off switch marking.
Rick,
My opinion based on my understanding of IEC 60950.
Whether an on/off switch breaks one or both sides of the line, the
equipment will be either on or off respectively, as either breaks the
electron path.
It is true that breaking only one side may leave the electronics "hot"
if the plug or socket allow for the neutral to be the "open" side. However,
the device will be off.
As I recall, the marking instructions you referenced make no mention of
whether one or both of the mains leads are opened by the switch. Therefore,
the "I" or "O" apply only to whether the device is on or off, which results
from
breaking either or both sides of the line.
George Alspaugh
Lexmark International Inc.
"Rick Linford" on 04/27/2001
12:25:19 PM
Please respond to "Rick Linford"
To: emc-pstc%majordomo.ieee@interlock.lexmark.com
cc:(bcc: George Alspaugh/Lex/Lexmark)
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
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All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: EN60950 (UL1950, IEC 60950) On off switch marking.
Rick,
My opinion based on my understanding of IEC 60950.
Whether an on/off switch breaks one or both sides of the line, the
equipment will be either on or off respectively, as either breaks the
electron path.
It is true that breaking only one side may leave the electronics "hot"
if the plug or socket allow for the neutral to be the "open" side. However,
the device will be off.
As I recall, the marking instructions you referenced make no mention of
whether one or both of the mains leads are opened by the switch. Therefore,
the "I" or "O" apply only to whether the device is on or off, which results from
breaking either or both sides of the line.
George Alspaugh
Lexmark International Inc.
"Rick Linford" on 04/27/2001
12:25:19 PM
Please respond to "Rick Linford"
To: emc-pstc%majordomo.ieee@interlock.lexmark.com
cc:(bcc: George Alspaugh/Lex/Lexmark)
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:
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 Healddavehe...@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,"
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:
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 Healddavehe...@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,"
