Answer / virendra

Mr. sunil.

The possible causes are.

1. Unbalance load
2. loose connection
3. Harmonics in the system

Answer / sunil guru

the current rating is greater than the MCCB rating. so go for
higher current rating...

Answer / m v v s n murthy

Generally, we will distribute our 1 phase loads equally in 3
phases to get the balanced load and the circuit becomes star
connected. In star connection, there will be no current in
neutral line if the load is balanced.

In the lighting loads also we have to distribute equally in
3 phases. If not, current will increased in neutral.

In your case you did not devide the lighting load to get
balanced star connection, and also the neutral link in your
MCCB under size to carry unbalanced neutral current. And
also there may be loose connection at neutral link.

Answer / sachin

Dear friend ,

First measure the current flowing thro MCCB .If it is MCCB
then it must have protective system . Set it as per max
current.measure the neutral current at full load. measure
neutal to earth voltage . most possible reasons are

1] Neutral link is undersized or

2] Loose connections

3] Neutral is not properly earthed .

Answer / anirudha

the mccb is burning because the rating for the current for
which it is selected may not be proper

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