[PaulL]

What are the symptoms of a 200 amp zinco service breaker going bad? Our lights are surging when major appliances run. PG&E (power company) came out and checked and there was not a bad neutral and connections are good. Thanks for any advice.

[tkrussell]

OK need to go over the word surge, and the symptoms. Surge would mean voltage swell, or increase in voltage, and the lights would get brighter. This can be caused by a broken neutral in a 3 wire feeder, just like the feed from the utility.

If the lights are dimming when the appliance starts, that is a voltage sag, or a decrease in voltage. This can be due to voltage drop caused by a loose or corroded connection, or contact points in a circuit breaker.

Zinsco breakers are not too popular on the east coast, at least what I have seen.

I do recall an issue with Zinsco:

Zinsco Sylvania Kearney Electrical Panel and Circuit Breaker Hazards, Failures, Inspection, Detection, Repair, Replacement - Sylvania Zinsco circuit breakers and panel hazards

There are ways of confirming bad contacts in a circuit breaker, but a service electrician that has special equipment, such as a DLRO, Digital Low Resistance Ohm-Meter, or a Milli-volt-Meter, needs to test the unit.

Would be a waste of money testing a unit that already has a known problem. Money better spent on replacing the panelboard.