Littelfuse POWR-PRO LDC series Class L fuses represent another first in fuse protection. LDC series fuses are the first UL Listed 600 volts AC and DC Class L fuse. Since they may be used for both AC and DC, they eliminate the concern that AC only fuses may be inserted into DC circuits. While LDC series fuses' UL Listed DC interrupting rating is more than adequate for most applications (50,000 amperes at a 16 millisecond time constant), tests in our high power testing laboratory have shown that this remarkable fuse is capable of performing at much longer time constants. This makes the fuse uniquely suited for such applications as crane rail circuits and mass transit systems. Contact the factory for application information for special needs such as this. For AC only systems, consider the use of POWR-PRO KLPC series fuses. They have a full ten seconds time-delay at 500% rated current, and have a wider range of ratings.