Mersen NRN (250 V) and NRS (600 V) fuses are standard non-time delay fuses, with a 10 kA short circuit rating. 250 V NRN15 through NRN60 fuses are certified as type P fuses, satisfying the Canadian electrical code for low melting point non-time delay fuses. also qualifying for type P are OTN15 through OTN60, which are Class K-5 fuses with a 50 kA short circuit rating.