After replacing the main panel board of our 2.5HP split type aircon. We started to experience tripping of our MAIN 150 Amp Circuit Breaker (CB1). This 150 Amp Circuit Breaker is outside our house (at the Electrical Post) which is standard in our Country. I wanted to have the Circuit Breaker trip to happen inside our house so I installed a similar 150 Amp (CB2) (same brand) inside our house. However, when the trip happens it still happens at the outside circuit breaker (CB2). The tripping is intermittent it only happens when certain appliances are operated at certain conditions. We have isolated that when we a. use the 2.5 HP aircon tripping happens b. use the Water Heater (at highest level (level 3). It causes tripping. However, the tripping always happens at CB1 not at CB2?. After the initial rewiring I was expecting that the tripping should happen at the inside CB.
The 2.5hp aircon is connected to 30amp CB which is connected to a 100amp sub-panel CB then connected to the inside 150amp main CB before being connected to the 150amp electrical post CB. But always tripping happens at the 150amp electrical post CB.
The Water Heater is also connected to 32 amp CB which is connected to a 60amp sub-panel CB then connected to a 100amp sub-panel CB then connected to the inside 150amp CB before being connected to the 150amp electrical post CB.
The Water Heater and 2.5HP aircon are on not on the same sub-panel which are both 100amp.
But always the tripping happens at the outside 150Amp CB outside the house.
Questions: a. Why is the tripping happening at the outside 150amp CB not at the inside 150amp CB? b. Why are not the inside CB not tripping: 30amp, 100amp, 150amp?