After an earthquake the sub panel in our guest house began to heat and the smell of smoke was present. I opened the breaker box and removed the breaker that was hot and noticed that sparks were comming from the nueteral buss and the only way I could stop the sparks was to pull all four breakers and then the box cooled down to normial. None of the breakers were thrown. When I tried to replace the breakers the same thing happened. Do I need to replace the breaker box? This is an old system that didn't use a ground, only the nuterial buss.