UNE 21120-2:2021

This standard specifies requirements for expulsión fuses designed for use outdoors or indoors on alternating current systems of 50 Hz and 60 Hz, and of rated voltages exceeding 1 000 V.Expulsión fuses are fuses in which the arc is extinguished by the expulsión effects of the gases produced by the arc.Expulsión fuses are classified according to the TTR (transient recovery voltaje) capability in clases A and B.This standard covers only the performance of fuses, each one comprising a specified combination of fuse-base, fuse-carrier and fuse-link which have been tested in accordance with this standard; successful performance of other combinations cannot be implied from this standard.This standard may also be used for non-expulsion fuses in which the interruption process waits for natural current zero to clear the circuit.