It seems that the diffferent safety standards have different mains supply
tolerance.
IEC 950/1991 (including amendment 1-4) says "Equipment intended to operate
directly from the mains supply shall be designed for a minimum supply
tolerance of +6%, -10%. If the rated voltage is 230 V single phase or 400 V
three phase, the equipment shall operate safely within a minimum supply
tolerance of +10% and -10%". (point 1.6.5)
The EN60950 has no national deviation at this point.
The new IEC950/1999 has a little different wording, but the same meaning.
Regards
Niels Hougaard
EMC and Safety
BARCO AS/Communication Systems
Denmark
> -----Original Message-----
> From: raymond...@dixonsasia.com.hk [SMTP:raymond...@dixonsasia.com.hk]
> Sent: 3. august 2000 04:16
> To: James, Chris
> Cc: emc-p...@ieee.org
> Subject: RE: Test voltage for products to the U.K.
>
>
>
>
> Chris,
>
> According to the Minister for Energy from DTI, the nominal mains voltage
> is
> 230Vac. The designer designs the products for 230Vac following such
> official
> information. The BS EN 60065 requires the test to the product +6 or -10%
> of
> rated voltage. It appears they are legally right and it seems the memo
> mentioned earlier (I have not seem the HD doc) is just a recommendation.
> Testing to +6% of 240Vac is just an option and not all test laboratories
> implement mandatorily. That is the reason I bring up this subject for
> open
> discussion. Is there any way in existence to block this loose hole?
>
> Regards,
>
> Raymond Li
>
> =======================================================
>
>
>
> "James, Chris" <c...@dolby.co.uk> on 02/08/2000 11:14:26 p
> Please respond to "James, Chris" <c...@dolby.co.uk>
> To: Raymond Li/DixonsNotes@DixonsNotes
> cc: emc-p...@ieee.org
> Subject: RE: Test voltage for products to the U.K.
>
>
>
>
> Equipment must be marked to include 230Vac in the supply range. For a wide
> input range PSU it is permissable to put say 90-240Vac as 230Vac falls
> within this range. For selectable ranges then 230Vac must appear as one of
> those ranges although it is acceptable to say 100/120/220/230-240.
>
> Section 4 of EN60065 says equipment must be tested at .9 and 1.06 times
> the
> RATED SUPPLY VOLTAGE, where RATED SUPPLY VOLTAGE is defined as the voltage
> for which the manufacturer has designed the apparatus.
>
> Thus if you spec/mark it to work at 240Vac then it will be tested at 254.4
> and if you spec/mark it to work at 230Vac then I read it as only being
> tested at 243.8Vac. However the test house (part of a world wide group) we
> use say they use 230 +10% or 240 +6% which is approximately the same
> thing.
>
> Chris
>
>
>
> -----Original Message-----
> From: raymond...@dixonsasia.com.hk
> Sent: Wednesday, August 02, 2000 9:52 AM
> To: James, Chris
> Cc: emc-p...@ieee.org
> Subject: RE: Test voltage for products to the U.K.
>
>
> Chris,
>
> Thanks for your comments.
>
> Generally, the product is marked 230Vac in order to comply with harmonised
> standard but for the products to the U.K., they should be tested at 207Vac
> (-10% of 230Vac) and 254.4Vac (+6% of 240Vac). Is it a normal practise or
> agreed
> procedure used in all accredited laboratories in the U.K. and/or elsewhere
> in the world?
>
> Best regards,
>
> Raymond
>
> =========================================
>
> "James, Chris" <c...@dolby.co.uk> on 01/08/2000 09:44:20 p
> To: Raymond Li/DixonsNotes@DixonsNotes, emc-p...@ieee.org
> Subject: RE: Test voltage for products to the U.K.
>
>
> Spec on mains is 230 +/- 6% so as 240 falls within that range, then that
> is
> where the reference regard the UK staying at 240Vac came from.
>
> We used to see voltages several % above 240Vac in the past. In my
> particular area they used to stay spot on 240V most of the time. I note
> however that in the last 6 months the local voltage has dropped to 235Vac,
> although the generating board won't admit to having consciously made this
> change!
>
> We here continue to design for 264Vac max.
>
> Chris
>
> -----Original Message-----
> From: raymond...@dixonsasia.com.hk
> Sent: Tuesday, August 01, 2000 10:53 AM
> To: emc-p...@ieee.org
> Subject: Test voltage for products to the U.K.
>
> A few years ago, BEAMA or other similar body has issued a memo to public
> laboratories about testing voltage for products selling in the U.K. The
> memo
> says the U.K. mains is still 240Vac although the rated voltage is agreed
> to be
> 230Vac and the products have to be taken care the safety at 240Vac. Can
> anyone tell me where I can find a copy of this memo and if there is any
> updated
> version to replace this one.
>
> Thanks and regards,
>
> Raymond Li
> Dixons Asia Ltd.
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