You lost me at
Do you mean you plug your modified to ground-only cable into a wall socket that is turned off? The other side goes onto a grounding lug on the device?
I am assuming on the socket where you plug in the C13 plug of your "regular" power cable into your device you would want that ground conductor disconnected yes?
... and insert power plags into a switched of mains socket, ideally on a different circuit.
Do you mean you plug your modified to ground-only cable into a wall socket that is turned off? The other side goes onto a grounding lug on the device?
I am assuming on the socket where you plug in the C13 plug of your "regular" power cable into your device you would want that ground conductor disconnected yes?