Short Description:

1. Application: For protecting cables and equipments against overload and short circuit.

2. General rules for choosing MCB.

a. Technical data of the network at the point considered: The earthing systems, short-circuit current at the circuit breaker installation point, which must always be less than the breaking capacity of this device, network normal voltage.

b. There are 3 curve characteristics for magnetic operation: B curve(3-5 In) protection and control of the circuits against length cables in TN and IT systems.

c.  curve(5-10 In) protection and control of the circuits against overloads and short-circuits; protection for resistive and inductive loads with low inrush current.

Dcurve(10-20 In) protection and control of the circuits against overloads and short-circuits; protection for circuits which supply loads with high inrush current at the circuit closing(LV/LV transformers, breakdown lamps).