A new grounding system may help the circuits that are already grounded,i.e. for electronics such as computers. The only way to ground ungrounded receptacles is to rewire them with new NM that has a ground in the cable. A 200 Amp upgrade does add capacity for the house. If 100 Amps is exceeded there could be some problems with the wire getting hot. If the panel has beeen upgraded why not go ahead and upgrade the service?! Sounds like it might be a good time to update all the wiring in the house. It won't be cheap but check with insurance about any benefits to upgrading the wiring, such as reduced rates, some co's in my area will lower rates if the house has been brought up to current code.
[This message has been edited by spkjpr (edited 08-14-2002).]
