[tsaksa]

Try unplugging all the circuit breakers and powering up the system again. All should be quiet. Then plug the breakers back in one by one until you discover which branch circuits are causing the problem and unplug them immediately. Power the system back down and then check the wiring carefully on any branch circuits that resulted in a problem. Look carefully for reversed connections (input for output) or reversed polarity (positive for negative). Look for the raised markings on the plastic. Do not trust the wire color or screw colors as they may have inadvertently got swapped.