A4BQ fuses are 20% more current limiting than any other Class L fuse on the market. When correctly coordinated, they bring a superior level of protection to service entrance equipment. Downstream circuit components have maximum protection against short circuit let‑thru current. A4BQ's built‑in, 4‑second time delay characteristic (at 500% of rated current) accommodates harmless inrush currents with no nuisance opening.