WE are using a 63A MCCB(SIEMENS MAKE) for one of the feeder
in LV substation panel.It is supplying to a lighting & power
socket DB.Settings in the MCCB is Ir = 63 * 1 , Isd = 8
times of Ir , tsd = 0.5 sec( I2 t off).
Sometimes this MCCB is tripping .But no trip in DB MCB.
Can anybody tell me reason ?
From where i can know about the MCCB settings?
Answers were Sorted based on User's Feedback
Answer / ranveer
Dear fren i think your Isd is very much high or it may
highest in. kindly che it out and may consult your vendor
Is This Answer Correct ? | 4 Yes | 1 No |
Answer / abdul
HI Friend,
I think there must be a earth leakage in your receiving end.
Always the MCB trips for Short circit,where as the MCCB
trips for both earth leakage & short circuit.
Is This Answer Correct ? | 1 Yes | 1 No |
Answer / kyle
Hi,
Is it instantaneous tripping? If it is, Isd might be too low
(in fact it is consider high in this case) and tsd might be
too short, need to check the downstream loads.
might to provide more info?
Is This Answer Correct ? | 0 Yes | 0 No |
This may be due to absense of discrimination feature in
DB.or cascading is not as per requirement.better to have a
word with siemens engineer
Is This Answer Correct ? | 1 Yes | 3 No |
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