[prairieschooner]

Ours aren't the basement type but we had a similar problem on our '82. I shortened the wires. The terminals on the circuit breaker were also in poor condition so it was replaced. I went through the switch panel at that time and corrected any short comings as well as isolating the circuits for the power inverter (the 2 televisions, an isolated outlet and microwave oven).
In my previous career maintaining a production facility, I would shut down the facility and bring in a short staff to help tighten all of the terminals throughout the switch panel. This was a large panel with most of the circuit breakers around 150 amp 440 Volt, three phase power. It almost always surprised me how some circuit breakers would need to be tightened.

After reading this post I think that I will be checking my switch panel again. I was taught to always disconnect any power (including the power inverter), check with a meter, and work as if it was still hot.