> Basically my question is, Is it standard practice to tie the SMPS DC
> ground to the mains earth?

In NZ, a typical 3-pin IEC connector to eg a computer has the green/
yellow earth wire to only the metal chassis.of the PSU, thereby to the
metal chassis of the PC and everything that is connected to the PC,
such as external amplifiers (for playback and recording audio/video)
and displays, which may or may not be 2-pin, 3-pin, earthed chassis,
earthed 0V, double-insulated etc

I have several 2-pin double-insulated appliances that I do/did not like
connecting together, for example plugging the mains earthed PC into
the 2-pin VCR. Often you're reaching around the back and if you've
got a finger on the RCA cup of the lead and a finger on the metal of
the socket you'll probably get a belt. The worst I felt was from a friend's
US-built 2-pin guitar amp when I plugged in an earthed echo unit.

Ouch, really really ouch

Joe
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