Yooper- I think we might be talking about 2 different animals. If we are talking about Service- then the grounded/grounding conductor are the same conductor and the conductor might be asked to conduct fault current at the service level, which would exceed Don's 20a. If we are talking about a sub panel, then the grounding conductor must comply with 250.122 because it would be expected to conduct current to trip the subpanel main overcurrent device. But the grounded conductor only has to be large enough to serve the maximum unbalance that could be imposed on the load- in Don's sample the maximum would be 20a. IMHO
[This message has been edited by George Little (edited 10-22-2004).]
