Square D CC42.7 Contactor Thermal Unit

Product Description

The SQUARE D CC42.7 is a thermal unit designed as an accessory for compatible contactors in electrical control systems. Thermal units serve as the overload sensing element within a contactor or overload relay assembly, detecting excess current draw by responding to heat generated under fault or overload conditions. When current exceeds the rated threshold, the thermal unit triggers the overload relay to interrupt the circuit, protecting motors and connected equipment from damage. Electricians and industrial maintenance technicians install these units as part of motor starter assemblies in commercial and light industrial applications.

This thermal unit is suited for use in motor control centers, panel-mounted motor starters, and similar low-voltage control applications where overload protection is required. It is installed into a compatible overload relay block alongside a contactor to form a complete motor starter. The CC42.7 is a direct replacement thermal unit for service and maintenance work where the original unit has tripped permanently or been damaged.

Key Features

• Thermal sensing element provides overload protection for motors and control circuits
• Compact form factor fits standard overload relay blocks designed for this unit class
• Sold individually, making it practical for single-unit service replacement
• Compact dimensions of 3.3 inches length, 2.2 inches width, and 0.8 inches height

Compatibility

Designed as an OEM-style replacement thermal unit for compatible Square D contactor and overload relay assemblies. Consult the overload relay documentation to confirm the correct thermal unit class and trip rating before installation.

Installation Notes

Thermal units are installed by licensed electricians or qualified maintenance personnel. De-energize and lock out the control panel per NFPA 70E arc flash and lockout/tagout requirements before handling any contactor or overload relay components. Verify the thermal unit class and current rating match the motor full-load amperage and the overload relay block specifications before installation. Do not force the unit into the relay block; proper seating is required for accurate trip response.