Electrical triping?
Answer:
do zoning of MCBs to avoide complete trip.
Since you ask this question I must assume you have checked your load versus your MCB rating.
"Early" tripping is usually due to the thermal element rather than the magnetic one. However, based on you "global" description it is difficult to be sure whether it tripped on the magnetic element rather than the thermal. If the current increases very slowly, it may trip on thermal rather than instantaneous. If that is the case, the three-phase fault may trip sooner due to the increased heat within the breaker.
For electronic trip, I'm not sure, but in theory the results should be the same.
Also, at very high levels of fault current, the three-phase fault may cause the contacts to open more quickly than the single-phase fault because of the contact design in modern breakers. The contacts have a "reverse current" configuration that generates magnetic forces that tend to force the contacts apart. This force "assists" the spring in opening the contacts. For very high current faults, the contacts can part before the breaker actually trips. So maybe a three-phase fault would tend to open a little faster if current levels were very high.
Hope that gets you on the right path for your fault analysis.
Is it due to tripping of supply from Utility ? If yes , then you have to keep a stand by arrangement of adequate capacity.
there has 2 be a fault somewhere if it is not overload. chk ur system for any loose contacts of insulation flash.
You may consider some form of redundancy so the operation continues in the event one portion stops.
However, a trip is telling you something is wrong and should not happen. It may be so simple as the breaker is incorrectly sized or even faulty, it may be that something is intermittently causing a fault.
Intermittent faults are often difficult to resolve, you don't mention if the trip is a simple over current or if there is a "trip unit" with some other indication such as ground fault.
One option, depending on what the breaker is feeding, you may consider adding more breakers so that the loads are separated and easier to troubleshoot or consider higher level protection relays that offer more diagnostics.
The main circuit breaker may be old, and needs to be replaced. After a circuit breaker has tripped many times, it gets weak and tends to trip more often.
2nd Check the load on this breaker and see if you are overloading it.
3nd Separate the loads, by installing additional circuit breakers after the main circuit breaker. If the Main circuit breaker is tripping and the down stream breaker is not tripping then you have a coordination problem. You need to adjust the downstream circuit breakers so they trip before the main. Check the main breaker also, and make sure its trip setting is set as high as it needs to be set.
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