Square D A1.86 Contactor Thermal Unit

Product Description

The SQUARE D A1.86 is a thermal unit designed for use as a contactor accessory in overload relay assemblies. Thermal units are the sensing element inside overload relays — they respond to heat generated by excess current draw and trip the relay to protect motors and connected equipment. The A1.86 is a direct-fit accessory intended for installation into compatible Square D contactor and overload relay assemblies. At 0.04 pounds and measuring 2.4 inches in length, 1.2 inches in width, and 0.7 inches in height, it is a compact replacement component suited for trained electrical technicians performing motor protection maintenance.

Thermal units like the A1.86 are used in motor starter assemblies found in commercial and light industrial applications. They are selected based on the full-load amperage of the motor being protected and the ambient temperature conditions of the installation environment. Replacing a worn or tripped thermal unit restores proper overload protection without replacing the entire overload relay or contactor assembly. This part is packaged individually and sold in single-unit quantities.

Key Features

• Thermal sensing element for overload relay assemblies
• Compact form factor: 2.4 inches long, 1.2 inches wide, 0.7 inches tall
• Lightweight at 0.04 pounds for easy handling during installation
• Single-unit packaging for targeted maintenance or repair
• Functions as a direct contactor accessory replacement component

Compatibility

Designed as an OEM-style replacement thermal unit accessory for compatible Square D contactor and overload relay assemblies. Verify the specific amperage rating and relay series requirements before installation to confirm fitment.

Installation Notes

Thermal unit replacement should be performed by a licensed electrician. De-energize and lock out the panel or motor control center before accessing the contactor or overload relay assembly. Follow NEC guidelines for motor branch circuit protection when servicing motor starter components. Do not reuse a thermal unit that has been mechanically tripped or visibly damaged.