John,
I would also agree with Mike Rain's comment.
It has always been my experience that the end-product drives the
determination of the standard to which it is to be evaluated against. Once
you have determined that your product falls under the scope of IEC 1010 as
defined in clause 1.1, that becomes your based standard. And unless IEC
1010 specifically requires that transformers comply with IEC 742, you would
not be required to comply with IEC 742.
Having said this, I did a quick search of IEC 1010 for the term, "IEC 742".
The only hit I came across Clause 1.1.2 - "Equipment excluded from the
scope".
Clause 1.1.2 seems to only require, "transformers separate from the
equipment" to be in compliance IEC 742. If your transformer is installed
within your product behind a tool accessed enclosure, I would question the
interpretation of your third party.
For your reference, I have included excerpts from IEC 1010-1, Clause 1.1.2,
"1.1.2 Equipment excluded from scope
This Part 1 does not apply to:
- electrical power equipment, for example power electronics;
- machine tools and their controls (see IEC 204);
- Class 0.5, 1 and 2 alternating current watt-hour meters (see IEC 521);
- medical electrical equipment within the scope of IEC 601;
- biological amplifiers which link humans to equipment in research or
teaching contexts;
- type-tested and partially type-tested assemblies of low-voltage
switchgear
and controlgear (see IEC 439-1);
- circuits and equipment which are part of the building electrical
installation (see IEC 364);
- computers, processors and similar equipment, except as specified in
1.1.3
(see IEC 950);
- transformers separate from the equipment (see IEC 742);
- equipment intended for household use (see IEC 335);
- equipment intended for use in explosive gas atmospheres (see IEC 79)."
Hope this helps! Let us know how things turn out!
Tin
In a message dated 97-02-05 14:15:26 EST, [email protected] (Rains,Mike)
writes:
<< 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. >>
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Date: 97-02-05 14:15:26 EST
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]
>>-------------------------------------------------------------
>
>
