Square D A3.95 Contactor Thermal Unit

Product Description

The SQUARE D A3.95 is a thermal unit designed for use with contactor and motor starter assemblies. Thermal units serve as the sensing element inside overload relays, responding to heat generated by excess current draw to trip the relay and protect the motor or load from damage. This unit is a direct replacement component for compatible SQUARE D contactor assemblies and is installed by licensed electricians and HVAC technicians during routine maintenance or overload relay service. It measures 2.4 inches in length, 1.2 inches in width, and 0.8 inches in height, making it a compact insert-style element suited to panel and enclosure work.

Thermal units like the A3.95 are used in commercial and industrial motor control applications where overload protection is required. They fit inside the overload relay block of a contactor assembly and are selected based on the full-load amperage of the connected motor. Typical installations include motor control centers, HVAC compressor starters, pump panels, and fan coil unit controls. Selecting the correct heater element by ampere rating and matching it to the overload relay model is essential for proper trip-class protection.

Key Features

• Insert-style thermal heater element for use inside compatible SQUARE D overload relay blocks
• Provides overcurrent trip protection by responding to heat generated under overload conditions
• Compact form factor: 2.4 inches long, 1.2 inches wide, 0.8 inches tall
• Lightweight construction at 0.04 pounds for easy handling during installation
• Sold individually — package quantity of one unit

Compatibility

Designed as an OEM-style replacement thermal unit for compatible SQUARE D contactor and overload relay assemblies. Verify the specific heater element ampere range and relay model requirements before installation to confirm fitment.

Installation Notes

Installation should be performed by a qualified electrician in accordance with NEC guidelines. De-energize and lock out the panel or motor control center before removing or inserting thermal units. The heater element seats into the overload relay block — do not force or bend the element during insertion. Always verify the correct heater element selection against the motor full-load ampere rating and the overload relay heater selection chart.