Dear John People put all sorts of things in contracts, some more crazy than others.
I wanted to establish the fact that there is nothing to stop a purchaser placing a requirement on a supplier to apply the limits in IEC 61000-3-2 for equipment that consumes >16A/phase, and you have confirmed that this is so. But I don't agree with you that such a contract requirement would necessarily be "crazy". The Class A and Class B limits in IEC 61000-3-2 set absolute values of current, but the Class C limits are expressed as a percentage of the input current and so permit proportionally greater emissions for equipment with greater consumption. My view is that applying EN 61000-3-2 (especially its Class C) to equipment with current demand >16A/phase is quite feasible and far from being "hardly more realistic than a requirement for no emissions at all" as you put it. Perhaps my example might have been more palatable if I had used the example of equipment consuming 16.5A/phase. Of course, a better standard to call up in a purchasing contract would be IEC 61000-3-4, which sets limits for harmonic emissions for equipment consuming > 16A/phase from the public LV supply. I note that its "Stage 1 current emission values" are very similar to the Class C limits in IEC 61000-3-2 – helping to show that the idea of applying IEC 61000-3-2 to >16A equipment is not as crazy as it might at first appear. Thank you for the useful information about the differences between Cenelec and IEC versions of 61000-3-2. Regards, Keith Armstrong In a message dated 25/01/02 14:33:14 GMT Standard Time, [email protected] writes: > Subj:Re: EN 61000-3-2 applicability and let-outs > Date:25/01/02 14:33:14 GMT Standard Time > From: [email protected] (John Woodgate) > Sender: [email protected] > Reply-to: <A HREF="mailto:[email protected]";>[email protected]</A> > (John Woodgate) > To: [email protected] > > I read in !emc-pstc that [email protected] wrote (in <ad.1718da5d.298 > [email protected]>) about 'EN 61000-3-2 applicability and let-outs', on Fri, > 25 Jan 2002: > > Dear John > > Thank you for your replies. > > A couple of points... > > > > Optional application of standards: I believe there is nothing to stop > > purchasers from using any IEC standards in their contracts with > suppliers. > > So a purchaser of a 30A/phase equipment could specify that the > equipment > > must meet the emissions limits set out in IEC 61000-3-2. Nothing to do > with > > CE marking, of course, merely a private agreement. This was what I > meant by > > 'optional' in the below. > > But that is crazy! Pardon my French, but *there are no emission limits > for a 30 A equipment in the standard*. What you are saying is that a > purchaser might impose contractually limits appropriate for, say, a 5 A > equipment to a 30 A equipment, which is indeed true but hardly more > realistic than a requirement for no emissions at all. It falls into the > same category as the all too common 'contractual requirement', 'The > equipment shall comply with all British, European and International > Standards.'. Does that include the one for toilet paper? > > > > > Do I understand from the following correspondence... > > QUOTE > > > 4) My copy of EN 61000-3-2 has a paragraph at the end of its > Scope > > section > > > that says: > > > "Special equipment, which is not widely used and is designed in > such a > > way > > > that it is unable to comply with the requirements (limits), may > be > > subject > > > to installation restrictions. The supply authorities shall be > notified > > as > > > authorization may be required before connection." > > > > This gobbledegook was deleted by the Millennium Amendment (MA, aka A14 > > to EN61000-3-2). No-one could define 'special' and 'not widely used', > > when challenged to do so, so out it came! > > > > > So custom-made or low-volume manufactured equipment (even if > under > > > 16A/phase) does not have to comply with EN 61000-3-2, as long as > their > > users > > > check with their power suppliers that they are OK to be > connected. > > > > Yes, this is explained *properly* in clause 4 of the MA. > > UNQUOTE > > ... that although the 'gobbledygook' paragraph has been removed the > option > > to not comply with EN 61000-3-2 still exists as long as users check > with > > their power suppliers that they are permitted to connect the equipment > > concerned? > > > Yes. I suggest you get the edition of the standard that is notified in > the OJEC and see for yourself. Be careful! CENELEC in its 'wisdom' has > got out of step with IEC, so there is an amended First Edition of the EN > AND a 'Second Edition' which is actually 6 months out-of-date compared > with the amended First Edition, unless you are into kitchen appliances. > -- > Regards, John Woodgate, OOO - Own Opinions Only. > http://www.jmwa.demon.co.uk > After swimming across the Hellespont, I felt like a Hero. > PLEASE do NOT copy news posts to me by E-MAIL! >
