Alan,
You asked:
>When considering the protectively earthed SELV circuit below are
>all points of the circuit (A,B and C) deemed to be connected to
>protective earth or just the current return leg.
Yes, all points (A, B & C) depicted in the circuit in your drawing are, in
fact, electrically connected to earth. They may not be directly connected as C
is in this case, but all are electrically connected nonetheless. It is
important to note here that each circuit [NOT EACH POINT IN A CIRCUIT] is
"deemed" to be connected to earth if earth is connected to an appropriate
point
(usually a single point) in each circuit (e.g., the circuit supply return
leg).
Earthing requirements of IEC60950 referred to in previous emails of this
thread
must also be met, if your product is ITE.
I hope this clears this up as this concept draws on fundamental circuit theory.
The above represents only my humble opinion.
Comments?
Best regards,
Ron Pickard
[email protected]
