In Air circuit breaker LSIG protection unit is used. Without fault in cables (2 runs 3Cx150Sq.mm Copper, 1Kv grade, XPLE armored cable IR value is more than 550Mohm @ 500V Megger) and load section Long time Overcurrent protection is triggers and trips the unit.

We changed LSIG protection with new factory tested unit. Even then fault is persisting.

Please suggest the possible causes


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