Margot, I believe that as you appear to suspect the statement does seem to imply that if two dedicated lines are being used, the safety ground connections of their respective outlets (the U-shaped openings of the outlets) should be connected together, and in turn wired through a single ground wire back to the circuit breaker panel. However, I feel pretty certain that if that is what the statement intends to indicate, it is wrong.
While I am an electrical engineer and not an electrician, I suspect doing that would be neither code compliant nor proper practice. I suspect that your electrician will tell you that each dedicated line has to have its own safety ground connection running back to the panel together with its AC "hot" and neutral wires. (The "hot" connection, btw, being the smaller of the two vertical slots on the outlet, and the neutral connection being the longer of the two vertical slots, which is T-shaped on a 20 amp outlet).
Hopefully one of our electrician members will comment further.
Best regards,
-- Al
While I am an electrical engineer and not an electrician, I suspect doing that would be neither code compliant nor proper practice. I suspect that your electrician will tell you that each dedicated line has to have its own safety ground connection running back to the panel together with its AC "hot" and neutral wires. (The "hot" connection, btw, being the smaller of the two vertical slots on the outlet, and the neutral connection being the longer of the two vertical slots, which is T-shaped on a 20 amp outlet).
Hopefully one of our electrician members will comment further.
Best regards,
-- Al