|
From: emc-pstc@ieee.org on behalf of Scott Xe [scott.xe@gmail.com]
Sent: Friday, September 14, 2007 7:05 AM
To: emc-pstc@ieee.org
Subject: I O power switch
I have learnt that a single pole power switch is not allowed to be
marked with | for On function and O for Off function and only double
pole switch can be used such symbol to distinguish the type of switch.
If a single pole power switch is used, what is appropriate marking for
it. Is there any standard to set this rule?
Thanks and regards,
Scott
-----
From: emc-pstc@ieee.org on behalf of Barker, Neil [Neil.Barker@E2V.COM]
Sent: Friday, September 14, 2007 7:25 AM
To: 'Scott Xe'; emc-pstc@ieee.org
Subject: RE: I O power switch
Scott,
I believe this to be incorrect.
EN60950-1:2006 states, in Clause 1.7.8.3, Where symbols are used on or
near
controls to indicate ON and OFF conditions, they shall be the line | for
ON
and circle O for OFF. It is permitted to use the symbols O and | to
indicate
the OFF and ON positions of any primary or secondary power switches,
including isolating switches.
Nowhere does it state that these have to be two-pole switches, but if
they
are isolating switches, then they should be two-pole switches.
Best regards
Neil R. Barker CEng MIET HonFSEE MIEEE
Manager
Quality Engineering
e2v technologies (uk) ltd
-----
From: emc-pstc@IEEE.ORG on behalf of Steve Richardson, Blackwood Labs [srichardson@blackwood-labs.co.uk]
Sent: Friday, September 14, 2007 7:56 AM
To: emc-pstc@IEEE.ORG
Subject: RE: I O power switch
Scott,
In the case of EN 60335 then the off position should be represented by
the figure 0 (if figures are used) and any other position represented by
a higher figure (usually |) regardless of how many poles it disconnects.
Ref clause 7.10.
If the switch needs to be a double pole disconnection device (ie for a
stationary device with no other means of supply disconnection) then that
is a separate issue but there is no differentiation when it comes to
marking the on, off positions.
In fact the note of clause 3.8.2 states that 'the off position does not
imply all pole disconnection'.
Regards,
___________________________________________
Steve Richardson
Blackwood Compliance Laboratories
-----
From: emc-pstc@ieee.org on behalf of John Woodgate [jmw@jmwa.demon.co.uk]
Sent: Friday, September 14, 2007 8:11 AM
To: emc-pstc@ieee.org
Subject: Re: I O power switch
In message <46ea6ad5.26d7720a.4b20.26b5@mx.google.com>, dated Fri, 14
Sep 2007, Scott Xe <scott.xe@gmail.com> writes:
>I have learnt that a single pole power switch is not allowed to be
>marked with | for On function and O for Off function and only double
>pole switch can be used such symbol to distinguish the type of switch.
>If a single pole power switch is used, what is appropriate marking for
>it. Is there any standard to set this rule?
There is no such restriction in IEC 60417, but there may be in some
product safety standards. Which product safety standard applies to your
product?
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
There are benefits from being irrational - just ask the square root of
2.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
-----
From: emc-pstc@IEEE.ORG on behalf of John Woodgate [jmw@jmwa.demon.co.uk]
Sent: Friday, September 14, 2007 8:17 AM
To: emc-pstc@IEEE.ORG
Subject: Re: I O power switch
In message <90511C6E9D0A89419745854EACE4C7A8036B6091@whl46.e2v.com>,
dated Fri, 14 Sep 2007, "Barker, Neil" <Neil.Barker@e2v.com> writes:
>EN60950-1:2006 states, in Clause 1.7.8.3, Where symbols are used on or
>near controls to indicate ON and OFF conditions, they shall be the line
>| for ON and circle O for OFF. It is permitted to use the symbols O and
>| to indicate the OFF and ON positions of any primary or secondary
>power switches, including isolating switches.
>
>Nowhere does it state that these have to be two-pole switches, but if
>they are isolating switches, then they should be two-pole switches.
But what about the requirements of 3.4.6 in respect of double-pole
switching? The 'except' in the first paragraph doesn't apply in
countries where the 'Schuko' or 'Europlug' mains plugs are used, because
they are reversible.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
There are benefits from being irrational - just ask the square root of
2.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
-----
From: emc-pstc@ieee.org on behalf of Barker, Neil [Neil.Barker@E2V.COM]
Sent: Friday, September 14, 2007 8:31 AM
To: 'John Woodgate'; emc-pstc@ieee.org
Subject: RE: I O power switch
True, John. But even in the UK, this would rely on too many
opportunities
for incorrect connections over which the user has no control.
Also, I am not sure that I would like to rely on the grounding of the
Neutral conductor, as the point at which it is grounded could be a very
long
way away from the point of connection of the apparatus; sufficient, I am
sure, for there to be a measureable voltage between Neutral and Ground.
Regardless, two-pole disconnection is obviously preferable.
Best regards
Neil R. Barker CEng MIET HonFSEE MIEEE
Manager
Quality Engineering
e2v technologies (uk) ltd
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