inrush current

[elmorseyma]

rated current of the load is 14Amps and its inrush current is 3 times of its rated.

what is the suitable CB that should be used in both cases MCB and MCCB?

 

[petersonra]

rated current of the load is 14Amps and its inrush current is 3 times of its rated.

what is the suitable CB that should be used in both cases MCB and MCCB?

Does the manufacturer's instruction give you any hints?

For a branch circuit I think 20A is probably OK.

 

[coulter]

If I were concerned, I would check how long the inrush current lasts. Get a copy of the CB overcurrent trip curve. They are usually available on-line. See if the device starting current duration is under the trip curve.

At 14A, you are likely looking at a standard thermal magnetic trip. If it is a motor with a combination bucket, you may have a mag only CB. In tis case there will be some type of overload device.

At that current level there are not a lot of options with out spending a lot of money.

carl

 

[coulter]

general questions with out any specific information are hard to answer - there are too many variables. Just a suggestion: Perhaps you could add some specific application information, such as:
voltage level
number of phases
Motor Control center or panel board
industrial or commercial
motor load
lighting load
transformer

carl

 

[jim dungar]

rated current of the load is 14Amps and its inrush current is 3 times of its rated.

what is the suitable CB that should be used in both cases MCB and MCCB?

Are you worried that a normal branch breaker will trip on an inrush of 3x or do you want to make sure that it will?

Except in very few cases circuit breakers will not react quickly to a 3x current level (the minimum NEMA standard for a 200% value is 2 minutes).

In the US there are not many differences in MCB (main breakers) and MCCB (branch breakers). In many panels they often have identical characteristics except for their rated amperes.