Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 28B-500 found under Circuit Breaker Subassembly by Federal Pacific Electric Co. The National Stock Number assigned to this part is 5925013127502, and the Federal Supply Class is 5925 Circuit Breakers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 28B-500.