Extremely fast short-circuit response. 20,000 Ampere Interrupt Capacity (AIC). UL listed to standard 248-15. DC Tested to UL standard 198L. Box Dimension 6Lx 4Wx 2H. 5121. Class T-Fuse. 400A. Extremely fast short-circuit response. 20,000 Ampere Interrupt Capacity (AIC). UL listed to standard 248-15. DC Tested to UL standard 198L.