Short circuit is a dangerous fault that can cause serious damage, fire, and even small-scale explosions. It can occur for a number of reasons: due to faulty insulation or loose connections, an abnormal build-up of electrical currents within electrical wiring system, old or malfunctioning appliances with damaged plugs or power cords, deterioration of the wire casing due to punctures, wire-liquid encounter, etc.
When choosing the MPCB you should check its breaking capacity i.e., the maximum current that the device is able to “open” (or interrupt). The breaking capacity of the MPCB should be greater than the maximum short-circuit current calculated in that point of the system. This current does not depend on the motor nominal current, but on the characteristics of the upstream network.