Dead short?

My son tried to start his 70 Swinger today and got a huge ball of smoke from under the dash. Checking things out we found the ground wire that goes to the steering column was fried. Not melted insulation but, copper wire turned to ash fried. The key switch seemed a bit stiff to turn and didn't want to spring back from start to run. I haven't had a chance to check anything else out yet. This car has the usual amounts of hacked wiring. The wires at the bulkhead connector looked ok. I haven't checked the wires at the ammeter yet. Haven't done the Madelectricle fix on it yet either. Might be time to do it. Anyone seen a ground wire burn up like that?