Square D A8.38 Thermal Unit Brand: Square D. Part Number: A8.38. Square D, A8.38, Overload Heater, Melting Alloy, 600 V AC, 4.95 to 6.99 A Full Load, Class 20/Standard Trip, 2.6 in L x 1.7 in W x 3.5 in H Size, Plug-In Mounting, 40 deg C. Additional Description: SQD -A8.38 THERMAL UNIT. Catalog Description: Thermal Unit, Type S, Type A, melting alloy, Class 20..