Panel Design

Throwing your MCB or keepint it in a museum is your worry! I can only give technical advice here. MPCB is NOT a replacement for MCB and Relay. It is a replacement for Switch-Disconnector-Fuse-Unit and Thermal Overload Relay. During a severe short circuit, a fuse would operate in under 5 milliseconds, but an MCB may take about 10 to 20 milliseconds. Moreover, an MPCB's Overload I-t Curve is exactly matching that of the thermal overload relay, whereas an MCB's overload curve would not match that of the thermal overload relay. Now, the choice is yours.

If you didn't get it from what ElecExpert said, you don't have to throw out the MCB but you cannot use it with just a contactor, you will need to use a contactor AND a thermal over load relay.

Another issue however is fault capacity. In an MPCB, the ability to safely interrupt a fault is usually very high, often around 65kA, whereas in an MCB it is usually very low, often around 10kA. That is a significant factor in industrial controls. MCBs are Cheaper because they are residential devices that can SOMETIMES be used in light industrial applications, but that was not their designed intent.