Both suggestions above are accurate. However, It is usually a violation of local code to run the ground separate from the main panel. I agree with A2z that it sounds better, but it is sometime difficult to find an electrician who will do this for you. Just for the record, I did separate my grounds from the main panel. I took the time to explain my needs, well in advance of the job to convince the electrician that I knew exactly what I needed. One other point, regardless of the type of ground, the construction of the box you mount your hospital receptacle into can well determine the ultimate result. If the mounting box is metal, it is often grounded to the main panel. In that case, a separate ground can cause a loop, where you may get hum. If you use a PVC box to mount the hospital grade outlet into, you resolve this problem. Be warned though, the PVC has no capability to provide an emergency ground, so the ground screw on the receptacle is the only shot at getting that plug safe to ground. Be certain too, before you wire in that new receptacle, that you check its construction. Every brand of hospital grade receptacle sounds different, and even among the different brands there are several types of construction. I prefer the Hubbell brand, and be sure that it shows the golden copper color inside, where the business end of your male plug goes. The ones that are plated with the silver colored anti corrosion material (zinc?) sound terrible. Best luck.
