Very little to do with the topc in the header I'm afraid, but... This post raises a point which has concerned me for some time, and which I'd be interested in opinions from other sources on.
It is my impression (and it is only an impression - I have made no attempt to gather objective evidence) that it is increasingly common for new standards to be issued, and existing standards to be modified, with certain tests removed from the standard itself and replaced with a cross reference to another harmonised or IEC standard. This seems to be particularly true of mechanical tests (e.g. vibration, drop test, enclosure access). Standards writers would doubtless argue that this makes good sense because it make updating these specialist requirements easier, and it standardises (!) the requirements between different documents. Personally, it's a practice which annoys me and I think it is bad standard making. I say this on two grounds: 1. Few things annoy me more in relation to standards than spending a shed load of money on an enormous document which is supposed to be a comprehensive set of requirements and then discovering I have to spend a load more money to buy subsidiary standards in order to find out what the requirements of the main standard really are. It's difficult not to conclude that this is profiteering by the standards publishing bodies. 2. When you get a test certificate for an appliance which has been tested to (say) BSEN60950:1992 it would be nice to think you could tell exactly what requirements have been applied to the product. However, if one has to know which version of the subsidiary standards have been applied, the process quickly becomes a nightmare. 60950 may be a bad choce to illustrate this phenomenon - I'm not very familiar with it, although I know lots of other people on this list are. The problem is particularly prevalent in machinery standards, but it is also creeping into the main electrical safety standards (e.g. EN60204 and 60335). Personally I can see no reason not to give the full requirements of the subsidiary standard in the main standard, and to cross reference the subsidiary standard as well. That way, when you buy the main standard you get a completely comprehensive set of requirements, but if you want to see what might develop you can look at how the subsidiary standards have been changed since the main standard was last issued. I'd be interested in commends from others on this topic - especially anyone on the list who is closely involved in standards writing. Maybe if enough people agree with me I could turn this into a comment to be sent to someone who ought to listen. Regards Nick. At 12:17 -0400 24/9/99, Peter E. Perkins wrote: > PSNet > > The announcement of the availability of the update to IEC 60990, >shown below, has been circulating for a short time now. As Convenor >(Chairman) of this committee I had not generally circulated it to the PSNet >since it is not a product standard but a basic standard to be used by >product standards writing committees. As is usually the case, the >information in basic standards is excerpted or summarized in product >standards. Two IEC committees have been integrating this information into >their product standards for some time; IEC TC66/IEC 61010 (and the 1010 >derivitive EN, CSA and UL standards) and IEC TC74/IEC 60950 (and the 950 >derivitive EN, CSA and UL standards). The implementation of these >requirements into these two standards families is done in a slightly >different way and neither is a full copy of the IEC 60990 set of >recommended requirements. The certification requirements for the products >are contained in the end product standard. We expect to see ongoing >changes to the measurement of touch current at the product level to >accommodate the introduction of new technology which changes touch current >and exposes the user to this aspect of electric shock in some new way. If >you are a designer of test equipment making this measurement or want to see >the latest information regarding the measurement of touch current you >should buy a copy of this standard. > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
