On a 120/240 single phase 3 wire system the power company grounds the neutral at the transformer. The neutral is also grounded at the service entrance on the customer side. Obviously this makes a parallel path, that is the neutral conductor and the higher resistance earth are in parallel. The problem is that if the neutral conductor is opened the transfer switch for an onsite generator does not sense this. The loads in the building suddenly are connected in series with bad results unless the load is ballanced. Is there a way to sense the loss of the neutral connection and then tell the generator to start and take the load? Simple relays wont work because they would also be in series and not drop. Any suggestions??
17 years ago