Charles, et al, You question is rather simplistic, in my opinion.
From my more than 25 years doing safety & regulatory consulting
with dozens and dozens of companies both large and small, I find that the
experience of the design team is the key to meeting the requirements early on.
First timers (no prior experience having an outside lab test any
of their work for compliance) has a pretty low pass rate; no matter how much
advice is given during the design phase.
Design teams quickly gain experience ramp up & meet compliance
requirements on the next project or two providing the design is similar to
their earlier experience.
This level of competence can be confounded (made worse) if there
are substantial changes in the design team between projects. Newbies always
think they understand the needs and design accordingly; unless an experienced
team manager can ferret out the issue before testing and get them to change.
Additional features (especially radios) complicate the issue,
even for experienced design teams.
To specifically answer your question, first designs from an
inexperienced design team generally will need another pass (or more) thru the
lab to qualify. Experienced teams will have a high 1st time pass rate in most
cases.
To relate one scenario, a complex electronic research instrument
was developed by a 3 man team of PhD physicists who struggled when going thru
the EMC lab; they had no prior product certification experience. I had offered
to go to the lab with them but they thought they could handle it themselves.
They had no concept of the needs to provide the proper isolation between major
pieces (e.g. cables routinely pierced the chassis and made connexion well
within the equipment). After the 2nd failure the lab manager, a long-time
colleague, talked to me and said that they weren’t listening to his comments
about needed changes to fix it. Upon talking to them, they had dismissed him
as just a technician (ignoring his EE training and EMC lab experience) and they
believed that they knew better (but not good enough, as evidenced by the
continuing failure). So we had a ‘managerial discussion’ and I went to the EMC
lab with them from then on. The baling wire fixes tried at the lab showed
improvement when applied and led to installing proper connectors at the chassis
interfaces along with some other changes; it finally passed.
Others probably have more interesting cases to relate, too.
Does that fit with your experience?
:>) br, Pete
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 1067
Albany, ORe 97321-0413
503/452-1201
IEEE Life Fellow
IEEE PSES 2020 Distinguished Lecturer
<http://www.researchgate.net/Peter%20Perkins> www.researchgate.net search my
name
<mailto:[email protected]> [email protected]
Entropy ain’t what it used to be
From: Grasso, Charles [Outlook] <[email protected]>
Sent: Monday, May 24, 2021 7:47 AM
To: [email protected]
Subject: [PSES] What percentage of products pass first time?
Hello EMC gurus!
Calling all labs - In your experience how many products pass the Unintentional
Emissions
test first time?
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