Joe, A long time ago, ( I think you heard this story before ) I had a problem with one of my customers. It seemed after a thunder and ligtning storm the customer complained that they didn't have any power in their house. I went out and saw a 200 amp single phase service. There were 2 200 amp main service fuses and the rest of the panel had 40 Zinsco circuit breakers. All of the breakers tripped but the 2 main 20 amp fuses were good. I checked around, and reset all of the breakers and everthing worked OK. About a month or two later the same thing happened. This time it was a nice sunny dry day. The fuses were OK but all 40 circuit breakers tripped. I couldn't find anything. I knew the head lineman at the power company (POCO) and I asked him the check his transformer on the pole. ( Which was at the bottom of the driveway of my customer.) The POCO said that everything was OK. I think that after several months and a lot of phone calls, the POCO changed the transformer and everything was OK after that. My thoughts would be that there was a spike our surge that would trip the magnetic part of the circuit breaker but not affect the fuses.
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) I had a problem with one of my customers. It seemed after a thunder and ligtning storm the customer complained that they didn't have any power in their house. I went out and saw a 200 amp single phase service. There were 2 200 amp main service fuses and the rest of the panel had 40 Zinsco circuit breakers. All of the breakers tripped but the 2 main 20 amp fuses were good. I checked around, and reset all of the breakers and everthing worked OK. About a month or two later the same thing happened. This time it was a nice sunny dry day. The fuses were OK but all 40 circuit breakers tripped. I couldn't find anything. I knew the head lineman at the power company (POCO) and I asked him the check his transformer on the pole. ( Which was at the bottom of the driveway of my customer.) The POCO said that everything was OK. I think that after several months and a lot of phone calls, the POCO changed the transformer and everything was OK after that. My thoughts would be that there was a spike our surge that would trip the magnetic part of the circuit breaker but not affect the fuses.
