John, My understanding of IEC1010 is that IEC742 only applies to transformers that are stand-alone (not built in). Transformers that are built-in need only comply with the requirements in IEC1010. While there is no specific section for transformers in IEC1010, there is a section for doing short circuit tests on secondary windings (4.4.2.6). The transformers would also have to meet the applicable spacing requirements in Annex D and the dielectric strength requirements in 6.8 and other construction requirements as they apply (e.g., double insulation, etc.). Regarding IEC950, I can't think of an instance where a transformer that met IEC950 requirements would not also meet or exceed the IEC1010 requirements. There may be some conditions where it wouldn't, but I haven't run into one yet. I would challenge the interpretation that you received.
Regards, Mike Rains Foxboro Co. >---------- >From: [email protected][SMTP:[email protected]] >Sent: Wednesday, February 05, 1997 7:58AM >To: [email protected] >Cc: [email protected] >Subject: Re: Transformer Approvals > >Just wanted to thank you for your explanation. In this case, the >transformers are built in to the instrument, behind a panel that >requires a 'tool' (key locked) to gain entry. I did have some >confusion about this, because as you indicated, IEC 1010 doesn't >specify a specific transformer standard to follow. > >I guess that we now have (2) choices - > >1. Purchase and install transformers that have IEC 742 certification. > - or - >2. Purchase copies of both IEC 742 and IEC 950 and evaluate >whether the IEC 950 certified transformers meet the requirements >of IEC 742 for our equipment. This *may* involve additional testing >and would most certainly be more time consuming. Potentially it could >be less costly in the long run, as domestic manufacturers of general >purpose transformers seem to only be offering products with IEC 950 >compliance. To get a transformer with IEC 742 compliance, I'd have >to switch from using Signal Transformer to Legrand or some other >European company. > >----------------------------------------- >John Bielot >Canberra Industries >Applied Systems Division >e-mail: [email protected] >----------------------------------------- >> >>On 04-Feb-97 you wrote >> >> >>Hello from San Diego: >> >> >>IEC 742 (aka EN 60742) applies to transformers in general and >>stand-alone transformers in particular. >> >>IEC 742 contains some additional requirements for stand-alone >>transformers compared to those in IEC 950 (aka EN 60950). >> >>Unfortunately, IEC 1010 (aka EN 61010) does not contain specific >>transformer requirements, so IEC 742 can be invoked if the test >>house so chooses. >> >>If your transformer is built-in, then I believe a transformer >>complying with IEC 950 also complies with IEC 742. >> >>It may be that the test house is simply saying that an IEC 950 >>certified transformer, by definition (not by test), does not >>comply with IEC 742. In other words, they cannot accept, carte >>blanche, the IEC 950 certification as being applicable to >>IEC 1010, whereas they could accept IEC 742 certification. >> >>This may mean that the test house will need to conduct tests to >>demonstrate compliance with IEC 1010. >> >> >>Best regards, >>Rich >> >> >> >>------------------------------------------------------------- > >Richard Nute Quality Department > >Hewlett-Packard Company Product Regulations Group > >San Diego Division (SDD) Tel : 619 655 3329 > >16399 West Bernardo Drive FAX : 619 655 4979 > >San Diego, California 92127 e-mail: [email protected] >>------------------------------------------------------------- > >
