Hi John:
> > This came up at IEC TC74 WG8 and was the object of several
> > proposals. We could come to no agreement about whether Class III
> > included TNV, earth connections, internally generated voltages of
> > assorted energies, etc., so we dropped the subject. It plays no
> > part in the safety requirements of IEC 60950, so resolving the
> > issue was unimportant. There is a definition which you may use for
> > what purposes you like, but it will serve mainly as a concept, not
> > a requirement.
> >
> The definition of Class III is not the responsibility of the self-
> appointed rulers of the Universe, sorry, I mean IEC TC74, corporately,
> not individually. It is the responsibility of TC64. See IEC 61140.
Thank you for the reference to IEC 61140.
According to IEC 61140:
Class III equipment is "equipment relying on
limitation of voltage to ELV as provision for
basic protection, and with no provision for
fault protection."
While battery-operated equipment would nominally
be Class III, most laptop computers would not be
Class III due to the backlight voltage exceeding
ELV.
Furthermore, according to IEC 61140, such laptop
computers would be Class II.
I agree with Robert Johnson that these classes
serve mainly as a concept, and that the safety
requirements are largely independent of equipment
class.
My argument with the equipment class concept is
that few equipment are truly fit one of the
classes. I prefere to replace the word equipment
with the word circuit. Now, I can apply the
different class concepts to various parts of my
equipment and accomplish the safety design.
Best regards,
Rich
> From owner-emc-p...@majordomo.ieee.org Wed Aug 1 13:56:40 PDT 2001
> Received: from sanrel1.sdd.hp.com (sanrel1.sdd.hp.com [15.80.36.45])
> by hpsdlfsa.sdd.hp.com (8.9.3 (PHNE_18546)/8.9.3 SMKit7.02 sdd epg)
> with ESMTP id NAA25290
> for <ri...@hpsdlfsa.sdd.hp.com>; Wed, 1 Aug 2001 13:56:40 -0700 (PDT)
> Received: by sanrel1.sdd.hp.com (Postfix)
> id 48A1793D9; Wed, 1 Aug 2001 13:56:40 -0700 (PDT)
> Received: from localhost.sdd.hp.com (localhost [127.0.0.1])
> by sanrel1.sdd.hp.com (Postfix) with SMTP id 00071940A
> for <ri...@sdd.hp.com>; Wed, 1 Aug 2001 13:56:36 -0700 (PDT)
> Received: from ruebert.ieee.org (ruebert.ieee.org [140.98.193.10])
> by sanrel1.sdd.hp.com (Postfix) with ESMTP id B9EEB93D9
> for <ri...@sdd.hp.com>; Wed, 1 Aug 2001 13:56:29 -0700 (PDT)
> Received: (from daemon@localhost)
> by ruebert.ieee.org (Switch-2.1.0/Switch-2.1.0) id f71Kn2d16535
> for emc-pstc-resent; Wed, 1 Aug 2001 16:49:02 -0400 (EDT)
> Message-ID: <ae7vhjarega7e...@jmwa.demon.co.uk>
> Date: Wed, 1 Aug 2001 21:05:37 +0100
> To: emc-p...@majordomo.ieee.org
> From: John Woodgate <j...@jmwa.demon.co.uk>
> Subject: Re: Class III anomoly
> References: <200107311606.jaa21...@epgc196.sdd.hp.com>
> <3b683241.1010...@ma.ultranet.com>
> In-Reply-To: <3b683241.1010...@ma.ultranet.com>
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Content-Type: text/plain;charset=iso-8859-1
> X-Mailer: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
> Sender: owner-emc-p...@majordomo.ieee.org
> Precedence: bulk
> Reply-To: John Woodgate <j...@jmwa.demon.co.uk>
> X-Resent-To: Multiple Recipients <emc-p...@majordomo.ieee.org>
> X-Listname: emc-pstc
> X-Info: Help requests to emc-pstc-requ...@majordomo.ieee.org
> X-Info: [Un]Subscribe requests to majord...@majordomo.ieee.org
> X-Moderator-Address: emc-pstc-appro...@majordomo.ieee.org
>
>
> <3b683241.1010...@ma.ultranet.com>, Robert Johnson
> <robe...@ma.ultranet.com> inimitably wrote:
> > This came up at IEC TC74 WG8 and was the object of several
> > proposals. We could come to no agreement about whether Class III
> > included TNV, earth connections, internally generated voltages of
> > assorted energies, etc., so we dropped the subject. It plays no
> > part in the safety requirements of IEC 60950, so resolving the
> > issue was unimportant. There is a definition which you may use for
> > what purposes you like, but it will serve mainly as a concept, not
> > a requirement.
> >
> The definition of Class III is not the responsibility of the self-
> appointed rulers of the Universe, sorry, I mean IEC TC74, corporately,
> not individually. It is the responsibility of TC64. See IEC 61140.
> --
> Regards, John Woodgate, OOO - Own Opinions Only.
> http://www.jmwa.demon.co.uk
> This message and its contents are not confidential, privileged or protected
> by law. Access is only authorised by the intended recipient - this means
> YOU!
> The contents may be disclosed to, or used by, anyone and stored or copied in
> any medium. If you are not the intended recipient, please advise the sender
> yesterday at the latest.
>
> -------------------------------------------
> 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 Heald davehe...@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,"
>
>
-------------------------------------------
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 Heald davehe...@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,"
