NLS series fuses provide low cost protection for general purpose feeder and branch circuits when available short circuit currents are less than 50,000 amperes. they replace all class H fuses which have only a 10,000 ampere interrupting rating. they are suitable for use in many residential and smaller commercial and industrial applications. NLKP series fuses are Canadian "Code" fuses specifically designed to meet Canadian electrical code type P fuse requirements for residential use. they have a 10,000 ampere interrupting rating. However, to obtain the added benefits of time delay, current-limitation, and higher interrupting rating, consider the use of POWR-PRO™ IDSR Indicator™ fuses for circuits between 250 and 600 volts. the user gets all the benefits of time delay RK5 fuses plus the added benefits of a n indicating fuse that tells when it has opened. complete information on these fuses may be found in the POWR-PRO™ section of this catalog. for circuits up to 250 volts, see FLNR fuses in this section of the catalog.