"w_tom"

Ioslation transformer must still have the secondary (the 120
volt side) connected back to the building safety ground.


** Making it no longer an "isolation " transformer.


If not, then the appliance will 'float' - can become electrically
hot.


** The appliance's AC supply wiring will float - but nothing else since
it is all insulated from that wiring.


If the transformer is properly designed, then either it
has such a connection OR it has a dedicated grounding wire
terminal to make that necessary connection.


** A step-down / isolation transformer ought to have a ground terminal on
the outlet that connects to the METALWORK of the appliance via the third pin
of the plug.




........... Phil