Scag electrical issues

[Tncpower]

I have a Scag Liberty with a Kohler KT750 motor. The blades stopped during mowing, shutoff engine then would not restart. Found ground wire running from solenoid ground to engine ground melted. I cut the harness open to check wire bundle. The only wire melted was ground. Anybody have any ideas why only ground would be bad?

 

[ILENGINE]

The only two reasons would be high resistance causing heat and melting the wire, or high amperage from being shorted to battery voltage causing heat and melting the wire.