[RFI] EMI/RFI AC line filter design info?
ka5s at earthlink.net
Tue Sep 24 16:23:20 EDT 2013
I have spent about 30 years doing EMC engineering, with some of the
safety type thrown in, because safety and power line EMC filtering
cannot be separated. We Amateur Radio operators are perhaps uniquely
qualified, among those who use radio equipment, to design and build our
own, but when it comes to power line filtering, the SMART choice is to
find filters that are already qualified by test, listing and recognition
of Nationally Accepted Test Laboratories (NRTL's) as safe when used for
We used to say "UL Approved" though there are now a number of NRTL's
whose mark is accepted by the various jurisdictions who have electrical
and fire safety regulations. Luckily, we need not pay list price, there
being enough such filters available excess to the needs of overly
ambitious manufacturers. Some we can install ourselves but some, if we
want (among other things) Homeowner's or Renter's insurance to cover
damage from an unfortunate occurrence, we should not.
When installers or manufacturer's representatives modify an appliance or
add a filter to one, THEY assume liability for the consequence if it
fails. or the installation is done improperly.
Buy two and test one, but have an authorized representative or installer
put in the one you will USE. Cheap is rarely good enough after
something bad happens. If you *must* install one yourself, don't modify
the appliance yourself if a licensed electrician can; add it outside the
appliance with NRTL approved and marked wiring stubs and using good
electrical wiring practices including to-code wiring and enclosures.
Dead is a one-time thing. Live and be safe.
On 9/24/2013 1021, Ray, W4BYG wrote:
> The Corcom info was interesting but at $55 apiece totaled more than I want
> to spend. I need a couple. Thus, I prefer save the money and build/test
> them myself.
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