Eaton HMCP400W5C Motor Circuit Protector

The Eaton HMCP400W5C is a magnetic-only motor circuit protector (MCP) designed for motor branch circuit protection in industrial applications. As part of the Series C product family, this 400 ampere, three-pole device provides reliable instantaneous short-circuit protection while allowing the motor starting current to pass without nuisance tripping. The HMCP is intended to be used in combination with a separate overload relay and contactor to form a complete motor starter, meeting NEC requirements for coordinated motor protection.

Key Features

• Current rating: 400 A continuous

• Voltage rating: 600 VAC / 250 VDC maximum

• Number of poles: 3-pole configuration with common trip

• Frame size: J-K frame, Series C design

• Adjustable magnetic trip range: 1250-2500 A (field adjustable)

• Magnetic-only trip mechanism – no thermal overload element

• Terminal connections: Line and load terminals (non-aluminum compatible)

• Compact dimensions: 10.13" height x 4.1" length x 5.5" width

• UL489 listed as a motor circuit protector (MCP)

Technical Specifications

Principle of Operation

The HMCP400W5C contains a solenoid mechanism that reacts to high fault currents. When the current exceeds the magnetic trip setting, the solenoid pulls in and trips the breaker instantaneously, disconnecting the circuit. Because it has no thermal element, it will not trip on overloads; this function is delegated to an external overload relay. This separation allows precise coordination between short-circuit protection and overload protection, with the magnetic trip range adjustable from 1250 to 2500 amperes to accommodate different motor sizes and starting characteristics.

Applications

• Individual motor branch circuits in industrial control panels

• Motor control centers (MCCs) with separate overload relays

• Compressor, pump, and fan starters

• HVAC equipment requiring high fault current ratings

• Any application requiring magnetic-only short-circuit protection

Installation and Coordination

The HMCP is typically mounted directly upstream of a contactor. The magnetic trip setting must be selected to allow the motor's locked rotor current (typically 6-8x FLA) to flow without tripping, yet trip on higher short-circuit currents. The J-K frame design ensures compatibility with standard panel layouts, and the line/load terminals accept copper conductors for secure connections. Coordination with upstream feeders can be achieved by selecting appropriate trip settings.

The Eaton HMCP400W5C is a reliable, code-compliant solution for protecting motor circuits against short circuits while maintaining flexibility in overload protection selection.