The US product certification system seems confusing to those who have not grown
up with it and used it. It is divided, as has been discussed, between
commercial/industrial (OHSA regulated) and retail/consumer (local AHJ
controlled).
OSHA has pretty clear requirements but enforcement is
Hi Dürrer:
1. Self-declaration is not accepted by any jurisdiction (or by OSHA) in
the USA. However, safety certification is not mandatory (or enforced) in some
local jurisdictions.
2. Where the NEC is adopted by the local jurisdiction, the adoption may
have exceptions and
I think an example of the field inspection/label program not part of OSHA's
NRTL program would be the City of Los Angles Department of Building and Safety.
http://www.ladbs.org/services/core-services/plan-check-permit/product-approval/electrical-test-lab
Note, I did not confirm they are not also
Hello Dave/Bernd.
Just a comment/clarification. The field inspection/label program is not
part of OSHA's NRTL program despite some NRTL's that conducted this
service. I know it can seem confusing but there are also some non-NRTL's
that conduct these field evaluations, all of which are under state
Hello Bernd,
The requirement from the National Electrical Code is either an NRTL Listing or
approval by the local Authority Having Jurisdiction (AHJ). The latter option
means that a local electrical inspector or building inspector will look at the
equipment to determine whether they think it
Bernd,
I don’t know any jurisdiction that would accept a manufacturer self-declaration
if the jurisdiction is requiring a safety certification. An alternative to an
NRTL listing is an NRTL field inspection/label which is unique to each product
at each installation.
-Dave
From: Dürrer Bernd
Hello Ted, hello Regan,
Thank you for your clear statements on NRTL certification. Can you please
provide some guidance on the interpretation of the National Electrical Code
NFPA 70 (2020 edition), article 110.3, on the suitability of installation and
use in conformity with the NEC?
Thank you very much.
Best wishes
John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK
On 2020-02-19 12:20, Gert Gremmen wrote:
Basically any connection to an opamp can create unwanted susceptibility.
So a small cap to ground preceded by a suitable impedance for the
Basically any connection to an opamp can create unwanted susceptibility.
So a small cap to ground preceded by a suitable impedance for the
frequencies to be suppressed
will do the job.
What pins ?
Those that have a substantial length (compared to wavelength) on PCB (or
off PCB).
By
I see two apparent ways of keeping cellphone noise out of audio op-amps:
- 10 pF between + and - inputs;
- 47 pF (or similar) from output to inverting input.
Which is usually more effective? I suspect that the first one is, but I
see it less often.
--
Best wishes
John Woodgate OOO-Own
Hi Amund,
If you have the space on the board then a ground fill around the perimeter (on
all layers) probably won’t do any harm. Whatever ground fill strategy you
decide on for the signal layer I would make sure it is well connected with vias
to both of the adjacent planes along the edge
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