Robert wrote:

Things may be different in the UK (after all, "traceability" is short
for "legal traceability," and the law of legal metrology may be
different there), but in the US one of the necessary criteria for
traceability is "demonstrated competence."  There may be a
philosophical question whether "competence" can be "demonstrated" in
some manner other than by accreditation, but there is no practical
question.  Universally (in the US), this is done by becoming
accredited to the relevant ISO/IEC standard.

Best regards,

Charles

In message 20130812213441.YeQeM90U@smtp16.mail.yandex.net, Charles Steinmetz
writes:

Agreed, those are two very different things.

Tracability is about the instruments performance.

Accreditation (and certification) is a legal framework of trust
and responsibility, and it's waaaaaay too expensive for the
benefits you get.

Many larger companies could buy their own Josephson standard for
the money they waste on certificates and fancy stamps on their
multimeters every year.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

Hi Charles,
I've never heard of "leagal Tracability" in connection with calibration. Nist say "NIST adopts for its own use and recommends for use by others the definition of metrological traceability2 provided in the most recent version of the International Vocabulary of Metrology: "property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each
contributing to the measurement uncertanty" (International Vocabulary of Metrology - Basic and General concepts and Associated Terms (VIM)"
No mention of accreditation there. Competence may be implied but it's not a requirement, Accreditation is typically a contractural obligation. I'm in the UK but do a lot of work to North American legislation. I've been quality manager of an FAA approved instrument shop. The biggest drivers for accreditation are quality systems like ISO9000 and AS9100. but they don't automatically improve quality.
Companies overcalibrate lots of equipment. A good example is bench power supplies. An indication only sticker and use of a DMM when it's critical is all that is required.
A similar misconeption is the requirement for portable appliance testing (PAT) in the UK. There is no requirement for testing, just an obligation to ensure equipment is safe. Having a test program does not reduce liability in the case of an accident. It's the insurance companies who want testing. It used to be a similar situation with UL approval in the USA, but that is changing as individual States bring in legislation.

Robert G8RPI.

From: Charles Steinmetz csteinmetz@yandex.com
To: Discussion of precise voltage measurement volt-nuts@febo.com
Sent: Monday, 12 August 2013, 18:34
Subject: Re: [volt-nuts] HP 3457A

Robert wrote:

Things may be different in the UK (after all, "traceability" is short
for "legal traceability," and the law of legal metrology may be
different there), but in the US one of the necessary criteria for
traceability is "demonstrated competence."  There may be a
philosophical question whether "competence" can be "demonstrated" in
some manner other than by accreditation, but there is no practical
question.  Universally (in the US), this is done by becoming
accredited to the relevant ISO/IEC standard.

Best regards,

Charles

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