Pittiing on Zinsco Busbar- The Zinsco Canker

Pitting on Zinsco busbars is a very common defect with them. These panel were cheaply made and a poor design and replacement should be performed. Waiting for or risking total failure with an electrical  panel in my opinion is not a risk worth taking. If you have a Zinsco panel replacement is highly recommended.

http://www.ncwhomeinspections.com/Zinsco+Breaker+and+Panel+design