One-Time OT and OTN general purpose fuses provide low cost protection for feeder and branch-circuits serving lighting, heating, and other non-motor loads. OT and OTN fuses will safely interrupt available short-circuit currents up to 50,000 amperes in all ratings. OT and OTN fuses are not rejection fuses and care should be taken to ensure that replacement fuses do not have lower interrupting ratings than original fuses. OTN (15 throug 60) satisfy the Canadian electrical code requirement for Type P low melting-point, non-time-delay fuses. 250 Volts 20 amps OTN series.