Hi John:
> Is it not permitted to express a personal preference on this group? I
> *prefer, personally*, not to use printed board traces as parts of the
> PEC. I'm not suggesting that should be in IEC 60950 or any other
> standard.
Of course we express personal preferences in
this group! Almost every message is a personal
preference. :-)
The point of my message is to argue against your
personal preference as there is nothing inherently
wrong with PWB traces as part of the PE circuit.
Some SMPS use a grounded heat sink -- on the PWB
-- for the switching transistors. In this case,
the electrical circuit path from the heat sink to
the earth terminal of the IEC 60320 connector is
a part of the PE circuit, and must be capable of
carrying the fault current. Running a wire from
the heat sink to the terminal is a manual job,
and introduces two connections that are operator-
dependent whereas the PWB connections are not.
Another point... which I hesitate to mention...
is that, while Y2 capacitors require connection
to a PE return, some test houses require a PE
return for Y1 capacitors!
In my experience, PWB PE circuits are common,
and most difficult to obviate.
Best regards,
Rich
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