Mersen OT Series Series Ferraz Shawmut is Mersen. Mersen OT One-Time general purpose fuses provide low cost protection for feeder and branch-circuits serving lighting, heating, and other non-motor loads. OT fuses will safely interrupt available short-circuit currents up to 50,000 amperes in all ratings. Other Names: OT500, OT 500 Amp, OT-500, OT 500A, OT500A, OT-500A, OT 500 Product specifications Ampere 500 A Voltage rating 250 Vac, 250 Vdc Interrupt rating 50 kA Speed Fast-Acting Class Class K5 Shape Cartridge Blade Fuses Approvals UL, CSA, RoHS Substitute parts Bussmann NON Datasheet Mersen OT Datasheet Dimensions 2.56" Dia x 10.38" L (65.02x263.65mm) Item weight 2.6 lbs Other names OT500, OT 500 Amp, OT-500, OT 500A, OT500A, OT-500A, OT 500 WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.