As far as I know MCPs are always fully magnetic without any thermal element(they do have an adjustment on the instantaneous trip unit that permits motor starting currents to be tolerated).
They are usually found in Motor Control Centers to provide Short-circuit & Ground-fault protection for the motor circuit.
The motor controller's overload relay (with properly sized heaters) will provide overload protection, therefore no thermal component is needed in the MCP.
[This message has been edited by Redsy (edited 12-20-2002).]
