What is the difference between Motor Control Center (MCC) and Motor Control Panel (MCP) , and when we can consider the MCC as MCP
MCCs are UL listed assemblies and are pretty much defined by UL (and earlier NEMA).
MCP (motor control panels) are usually actually industrial control panels and can be UL listed as such.
They both provide motor starting and OCPD for the motors and associated conductors.
They are usually built completely differently, although I have seen MCPs that look a lot like the way MCCs are usually built.
MCPs usually service a group of motors that are functionally associated with each other, while MCCs usually serve whatever motors happen to be nearby. But, this is not always true.